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European Journal of Taxonomy 984: 1–131 ISSN 2118-9773
https://doi.org/10.5852/ejt.2025.984.2851 www.europeanjournaloftaxonomy.eu
2025 · Cicimurri D.J. et al.
This work is licensed under a Creative Commons Attribution License (CC BY 4.0).
Monograph
urn:lsid:zoobank.org:pub:7D8BB514-E8B7-403C-9725-B1405E214075
Late Oligocene shes (Chondrichthyes and Osteichthyes) from the
Catahoula Formation in Wayne County, Mississippi, USA
David J. CICIMURRI 1,*, Jun A. EBERSOLE 2, Gary L. STRINGER 3,
James E. STARNES 4 & George E. PHILLIPS 5
1,* South Carolina State Museum, 301 Gervais Street, Columbia, South Carolina 29021, USA.
2 McWane Science Center, 200 19th Street North, Birmingham, Alabama 35203, USA.
3 University of Louisiana at Monroe, Monroe, Louisiana 71209, USA.
4 Oce of Geology, Mississippi Department of Environmental Quality,
700 North State Street, Jackson, Mississippi 39202, USA.
5 Mississippi Museum of Natural Science, 2148 Riverside Drive, Jackson, Mississippi 39202, USA.
* Corresponding Author: dave.cicimurri@scmuseum.org
2 Email: jebersole@mcwane.org
3 Email: stringer@ulm.edu
4 Email: jstarnes@mdeq.ms.gov
5 Email: george.phillips@mmns.ms.gov
1 urn:lsid:zoobank.org:author:F0155EA1-F5D6-49E4-B578-7A14DBB7B902
2 urn:lsid:zoobank.org:author:D48E2A2F-EC92-4C32-9F2A-2D39716C459E
3 urn:lsid:zoobank.org:author:4E93392A-5916-44C6-B55A-9053A4F44C76
4 urn:lsid:zoobank.org:author: D4E14C23-EE57-4D1D-8709-895A1345C8BA
5 urn:lsid:zoobank.org:author: DFFC9021-05C6-4B56-BCD3-D54BCDE91351
Abstract. Isolated elasmobranch and teleost teeth, jaws, otoliths, scales, vertebrae, and n spines were
recovered from the upper Oligocene (Chattian) Catahoula Formation in Wayne County, Mississippi,
USA. A total of 13 551 specimens were examined and 12 340 of these were identied at least to the ordinal
level. These remains represent 49 unequivocal sh taxa, viz. 29 elasmobranchs and 20 teleosts. The 3614
elasmobranch remains indicate that Carcharhiniformes is the most diverse group of Elasmobranchii,
with 12 taxa belonging to ve families. Orectolobiformes and Lamniformes are represented by far fewer
taxa (three and four, respectively). Carcharhinus acuarius (Probst, 1879) constitutes 49% of the total
number of shark teeth in our sample. Ten batoids have been identied within Myliobatiformes (seven
taxa) and Rhinopristiformes (three taxa). Partial teeth of durophagous myliobatids (three genera) are
the most abundant batoid remains, constituting 41% of the total number of ray fossils. However, teeth
of Dasyatidae and Rhynchobatus cf. pristinus (Probst, 1877) are abundant and represent 36.5% and
15.4%, respectively, of the specimens identied. Herein, we erect ve new elasmobranch taxa, including
Galeocerdo platycuspidatum sp. nov., Hemipristis intermedia sp. nov., Hypanus? heterodontus sp. nov.,
“Sphyrna” gracile sp. nov., and “Sphyrna” robustum sp. nov.
The Catahoula Formation sample includes over 9935 teleost fossils, which constitutes 73% of the
total sh sample. Nine bony sh taxa are represented solely by teeth, jaw elements, or n spines.
Although otoliths are much less common than the other identiable remains (409 versus roughly 8430,
European Journal of Taxonomy 984: 1–131 (2025)
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respectively), they allowed us to identify four taxa not known from other skeletal remains. Albulidae,
Sciaenidae, and Sparidae are represented by isolated teeth, jaw elements, and otoliths, but we could not
ascertain whether the various teeth and jaw elements are conspecic with the otolith-based species we
identied. The remains of Sciaenidae (teeth, jaw elements, otoliths) dominate the Catahoula Formation
bony sh assemblage, constituting 70% of the teleost specimens identied at least to the ordinal level.
Our sample includes the rst Oligocene occurrence of Tetraodontidae in the Western Hemisphere.
The vertebrate assemblage within the Catahoula Formation at the study site indicates an estuarine
depositional environment, which is consistent with previous interpretations based on lithology. At the
study site the Catahoula Formation disconformably overlies the Paynes Hammock Limestone, and we
believe the disconformable contact locally represents the Rupelian (early Oligocene)/Chattian (late
Oligocene) boundary. The sh fauna described herein is therefore of Chattian age.
Keywords. Elasmobranchii, Teleostei, Paleogene, Oligocene, Chattian, Gulf Coastal Plain, Mississippi.
Cicimurri D.J., Ebersole J.A., Stringer G.L., Starnes J.E. & Phillips G.E. 2025. Late Oligocene shes (Chondr-
ichthyes and Osteichthyes) from the Catahoula Formation in Wayne County, Mississippi, USA. European Journal
of Taxonomy 984: 1–131. https://doi.org/10.5852/ejt.2025.984.2851
Contents
Introduction ............................................................................................................................................. 3
Material and methods .............................................................................................................................. 5
Institutional abbreviations ................................................................................................................ 6
Geological and stratigraphical settings ............................................................................................. 6
Results ..................................................................................................................................................... 8
Brachaeluridae Applegate, 1974 gen. et sp. indet. ............................................................................ 8
Genus Chiloscyllium Müller & Henle, 1837 .................................................................................... 9
Genus Nebrius Rüppel, 1837 .......................................................................................................... 10
Genus Otodus Agassiz, 1843 .......................................................................................................... 12
Genus Carcharias Ranesque, 1810 .............................................................................................. 13
Genus a. Pseudocarcharias Cadenat, 1963 .................................................................................. 16
Genus Alopias Ranesque, 1810 .................................................................................................... 17
Genus Hemipristis Agassiz, 1835 ................................................................................................... 18
Genus Physogaleus Cappetta, 1980a .............................................................................................. 26
Genus Rhizoprionodon Whitley, 1929 ............................................................................................ 30
Genus Carcharhinus de Blainville, 1816 ........................................................................................ 31
Genus Galeorhinus de Blainville, 1816 .......................................................................................... 34
Genus Pachyscyllium Reinecke et al., 2005 ................................................................................... 36
Genus Sphyrna Ranesque, 1810 ................................................................................................... 38
Genus Galeocerdo Müller & Henle, 1837 ...................................................................................... 45
Genus Rhynchobatus Müller & Henle, 1837 .................................................................................. 49
Genus Pristis Linck, 1790 .............................................................................................................. 51
Genus Anoxypristis White & Moy-Thomas, 1941 .......................................................................... 53
Genus Hypanus Ranesque, 1818 .................................................................................................. 54
Dasyatidae Jordan & Gilbert, 1879 gen. et sp. indet. ..................................................................... 63
Genus Myliobatis Cuvier, 1816 ...................................................................................................... 64
Genus Aetomylaeus Garman, 1908 ................................................................................................. 66
Genus Rhinoptera Cuvier, 1829 ..................................................................................................... 67
Genus Plinthicus Cope, 1869 ......................................................................................................... 70
Genus Paramobula Pfeil, 1981 ....................................................................................................... 71
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
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Batomorphi Cappetta, 1980b fam., gen. et sp. indet. ...................................................................... 72
Euselachii Hay, 1902 fam., gen. et sp. indet. .................................................................................. 74
Lepisosteidae Cuvier, 1825 gen. et sp. indet. ................................................................................. 75
Albulidae Bleeker, 1859 gen. et sp. indet. ...................................................................................... 76
Genus Protanago Schwarzhans, Stringer & Takeuchi, 2024 .......................................................... 78
Congridae Kaup, 1856 gen. et sp. indet. ......................................................................................... 80
Siluriformes Cuvier, 1816 fam., gen. et sp. indet. .......................................................................... 80
Genus Sphyraena Artedi in Röse, 1793 .......................................................................................... 81
Genus Syacium Ranzani, 1842 ....................................................................................................... 84
Genus Acanthocybium Gill, 1862 ................................................................................................... 85
Genus Scomberomorus Bleeker, 1859 ............................................................................................ 85
Labridae Cuvier, 1816 gen. et sp. indet. ......................................................................................... 86
Genus Allomorone Dante & Frizzell in Frizzell & Dante 1965 ...................................................... 87
Lutjanidae Gill, 1861 gen. et sp. indet. ........................................................................................... 89
Genus Aplodinotus Ranesque, 1819 ............................................................................................. 90
Genus Sciaena Linnaeus, 1758 ....................................................................................................... 92
Sciaenidae Cuvier, 1829 gen. et sp. indet. ...................................................................................... 94
Genus Diplodus Ranesque, 1810 .................................................................................................. 95
Genus Sparus Linnaeus, 1758 ........................................................................................................ 96
Sparidae Ranesque, 1818 gen. et sp. indet. .................................................................................. 97
Lophiidae Ranesque, 1810 gen. et sp. indet. ................................................................................ 98
Tetraodontidae Bonaparte, 1831 gen. et sp. indet. .......................................................................... 99
Teleostei fam., gen. et sp. indet ..................................................................................................... 101
Discussion ........................................................................................................................................... 101
Characteristics of the Catahoula sh assemblage ......................................................................... 101
Biostratigraphic and biogeographic implications of the Catahoula Formation sh assemblage .. 103
Paleoecology and depositional environment of the fossil deposit ................................................ 105
Conclusions ......................................................................................................................................... 107
Acknowledgments ............................................................................................................................... 107
References ........................................................................................................................................... 108
Appendices ......................................................................................................................................... 130
Introduction
Oligocene vertebrate faunas within the Gulf Coastal Plain are relatively unknown. Previous reports of
marine vertebrates from Alabama (i.e., Ebersole et al. 2021), Louisiana (Stringer & Worley 2003), and
Mississippi (Stringer et al. 2020c) documented various sh taxa largely based on otoliths, but a limited
number of teleosts and elasmobranchs have been identied based on teeth and other skeletal remains, as
for example in the Mint Spring Formation in Mississippi (Stringer & Miller 2001). Our understanding
of marine vertebrate paleofaunas from this region has recently been improved through the discovery of
a highly fossiliferous unit exposed along the banks of a tributary of the Chickasawhay River in eastern
Mississippi (Fig. 1A). The fossiliferous unit yielded a signicant sample of vertebrate fossils that have
provided a unique window into an ancient ecosystem.
Referred to herein as the Jones Branch locality, the fossil site was discovered by avocational collectors
in 2012. Jones Branch is a tributary of the Chickasawhay River, and the collecting site is located
approximately 1.4 km southwest of the intersection of Mississippi State Highway 184 and Mississippi
State Highway 63 (decimal degrees = 31.6618, -88.6564) in Waynesboro, Wayne County, Mississippi,
USA (Fig. 1B). The locality is designated as site MS.77.011 by the Mississippi Museum of Natural
Science, Jackson, MS, USA. Although access to the locality is possible, the fossil site has been covered
with riprap to prevent collapse of the cut bank, and the fossiliferous unit is no longer exposed for study.
European Journal of Taxonomy 984: 1–131 (2025)
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Fossils from the site were brought to the attention of GEP who, along with JES, conducted initial
investigations at the locality. It was determined that fossils were contained within argillaceous, shelly
quartz sand occurring in the lower part of the Oligocene Catahoula Formation. This unit is part of the
Jones Branch fossil horizon as utilized by Stults et al. (2024), and this informal term is used herein
when referring to the fossil bed we sampled. Preliminary analysis of fossils indicated the presence
of a diverse vertebrate paleofauna that includes cartilaginous and bony shes (teeth, skeletal remains,
and otoliths), marine and terrestrial mammals, and a herpetofauna containing amphibians and reptiles.
Further investigations by the present authors have revealed the true extent of the fossil assemblage,
Fig. 1. Geographic location of the Jones Branch fossil site. A. State map of the USA showing the location
of Mississippi (gray). B. County map of Mississippi showing the location of Wayne County (gray). The
dotted line represents the Oligocene shoreline based on state-scale surface geology. C. Detail map of
Wayne County showing the fossil site (designated by solid star at the base of the Catahoula Formation)
and the geologic units occurring in the area.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
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which is dominated by marine shes. The results of a comprehensive evaluation of the sh assemblage
are reported herein, where we describe the various fossils and identify the taxa represented. We also
comment on the morphological criteria we used to identify taxa, and we discuss taxonomic issues related
to the taxa identied. Furthermore, we comment on the paleobiogeographic and temporal distributions
of the taxa, as well as provide a paleoenvironmental evaluation of the fossil-bearing unit based on the
associated fossils.
Material and methods
With few exceptions, the specimens discussed herein were obtained from processed matrix samples
collected by DJC, GLS and GEP. Approximately 15 kg of bulk matrix from the fossil bed was screened
in the creek by DJC using #5, #10 and #20 (0.85 mm) US Standard Soil Sieves. These concentrated
fractions were individually bagged and brought to the laboratory, along with an additional 23 kg of
unprocessed matrix (wet). This matrix was disaggregated in water and gently screened down to #40
(0.42 mm) mesh size, but material passing through this screen was saved for examination. The remaining
concentrations of lithologic material and fossils were sorted under a binocular microscope. These Jones
Branch fossils are housed at the South Carolina State Museum in Columbia, USA and are catalogued
under accession SC2013.28.
A roughly 75 kg sample (weight was determined after it was air-dried) was collected directly from the
fossiliferous bed by GLS. The sample was screen washed with tap water using #5, #10, #20, and #35
(0.5 mm) screens. The remaining residues were examined with a stereoscopic binocular microscope using
6.7–40 × magnication. All otoliths that were at least one-half complete were targeted for examination,
and taxonomic identication was done by GLS. The otoliths from the GLS collection that are illustrated
herein are reposited in the scientic collections at the Mississippi Museum of Natural Science (MMNS)
in Jackson, Mississippi, USA.
Specimens exceeding 5.0 mm in greatest dimension were photographed with a Nikon D-80 camera with
a Tamron macro-lens. Specimens smaller than 5.0 mm in greatest dimension were photographed with a
Wild Photomakroskop M400 microscope with a mounted Canon Eos R50 camera. To account for depth
of eld, specimens were photographed from several focal lengths and the resulting photographs were
stacked and merged in Helicon Focus 8 software. The nal plates were produced in Adobe Photoshop
ver. 22.5.9. Photographs of sagittae showing the inner surface are oriented with the anterior margin
at left, and right sagittae were therefore used as possible. However, when the left sagitta was used we
indicated within the gure caption that the image was reversed (so that it appears as if it were a right
sagitta)
The classication scheme utilized herein largely follows that of Nelson et al. (2016), which was
inuenced by the molecular research of Betancur-R. et al. (2013), but any departure from their hierarchy
is noted. Ordinal names were typically based on Wiley & Johnson (2010), and family-group names
and authors follow Van der Laan et al. (2014). Authorships for genera and species are based primarily
on Eschmeyer’s Catalog of Fishes: Genera, Species, References (Fricke et al. 2019). To aid in the
anatomical and taxonomic identication of fossils, material was, whenever possible, directly compared
to extant elasmobranch jaws and bony sh skeletons housed in the collections at McWane Science
Center, Birmingham, Alabama, USA, the South Carolina State Museum, Columbia, USA, and the
research collection (otoliths) of one of the authors (GLS).
Institutional Abbreviations
GCVP = Georgia College and State University, Milledgeville, GA, USA
MSC = McWane Science Center, Birmingham, AL, USA
MMNS = Mississippi Museum of Natural Science, Jackson, MS, USA
SC = South Carolina State Museum, Columbia, SC, USA
European Journal of Taxonomy 984: 1–131 (2025)
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Geological and stratigraphical settings
The sh fossils described herein were recovered from the upper Oligocene (Chattian) Catahoula
Formation at site MS.77.011 in Wayne County, Mississippi, USA. The Catahoula Formation extends from
Texas to Alabama in the USA and attains a maximum thickness exceeding 240 m in central Louisiana
(Dockery & Thompson 2016). Exposures of the Catahoula Formation are common throughout its outcrop
belt, except where it is obscured by post-Pleistocene alluvium. Marginal marine to deltaic impure clays
(silty-to-ne sands) occur throughout the section. The clays are interspersed with interbedded distributary
channel and thick deltaic sands having grain sizes ranging from ne to coarse and graveliferous. The
Catahoula Formation underlies the Hattiesburg Formation of Miocene age, and in western Mississippi
it disconformably overlies lower Oligocene (Rupelian) strata of the Vicksburg Group. In western
Mississippi the Catahoula Formation is laterally (temporally) equivalent to the Paynes Hammock
Limestone, but in the eastern part of the state the Catahoula Formation disconformably overlies the
Paynes Hammock Limestone (Fig. 2A).
A stratigraphic test hole, MGS N-12, located near site MS.77.011, was initiated by the Mississippi
Geological Survey in 1972 and an electric log was obtained (May et al. 1974). The data collected,
combined with our observations at the site, demonstrate that the Catahoula Formation and Paynes
Hammock Limestone are present at the fossil locality (Figs 1C, 2B). Additionally, the Chickasawhay
Limestone (which underlies the Paynes Hammock Limestone) occurs in the subsurface (Starnes &
Phillips 2016). The subjacent Chickasawhay Limestone and Paynes Hammock Limestone both contain
the planktonic foraminiferan Chiloguembelina cubensis (Palmer, 1934), a species whose extinction
marks the Rupelian/Chattian stage boundary (King & Wade 2017; Li et al. 2023). The age of the
boundary at the Global Stratotype Section and Point is between 27.82 and 27.41 Ma (Coccioni et al.
2018). The unconformable contact between the Paynes Hammock Limestone and overlying Catahoula
Formation demonstrates an abrupt change from carbonate to clastic deposition and is considered
herein to represent the Rupelian/Chattian boundary. The Jones Branch fossil horizon at site MS.77.011
is therefore considered by us to be of Chattian age, although no calcareous nannofossils have been
described from the Jones Branch fossil horizon to help place exactly when the unit should be correlated,
and deposition within Zone NP25 (late Chattian) has been proposed (Starnes & Phillips 2016; Stults
et al. 2024). If our timing is correct, the disconformable contact between these two lithostratigraphic
units could also reect regression related to Rupelian glaciation (erosion) and subsequent transgression
(deposition) during Chattian warming (Van Simaeys et al. 2004; Pälike et al. 2006). The portion of the
Catahoula Formation exposed at the Jones Branch locality stratigraphically occurs well below the last
regional occurrence of the benthic foraminifer, Heterostegina, a marker taxon for the upper beds of the
Catahoula Formation. We note here that this marker horizon was previously placed immediately above
the top of the Paynes Hammock Limestone (Dockery & Thompson 2016), but the marker zone and base
of the Catahoula Formation are separated by several hundred feet (Fig. 2A).
The Paynes Hammock Limestone consists of glauconitic, sandy-clay marl and soft limestones dominated
by thin discontinuous reefs of the large oyster, Crassostrea blanpiedi (Howe, 1937). The top of the
Paynes Hammock Limestone is marked by a distinctive bed that is a thin, ne-grained, sandy, indurated
ledge with well-preserved primary structures of ripple marks on its upper surface. Its upper contact (with
the Catahoula Formation) is interpreted as once belonging to a sandy tidal at truncating the underlying
marine deposits of the Paynes Hammock Limestone (Starnes & Phillips 2016).
The Catahoula Formation consists of unweathered dark gray-green, carbonaceous ssile clays. The
clays are interrupted by a series of thin coeval sands that are tidally inuenced distributary channel
lenses along a narrow horizon. Combined, the post-Paynes Hammock deposits represent an emergent
delta with brackish water and terrestrial inuences grading upwards to massive and more uniform, non-
fossiliferous freshwater clays. The clays contain an excellently preserved ora that includes lignitized
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
7
Nyssa sp., endocarps and leaf compressions of Lauraceae, palms, and other undescribed morphotypes
with entire or toothed margins (a long grass blade is encrusted with barnacles). The ora is indicative
of a warm-temperate to subtropical estuarine paleoclimate (Baghai-Riding et al. 2018). The sand
lenses contain a lag of phosphatic nodules, marine invertebrates (mollusks, crustaceans, brachiopods,
echinoderms), and vertebrate remains of both marine (sirenians, cetaceans, elasmobranchs, teleosts) and
terrestrial (rodents, ungulates, carnivores, reptiles) taxa. Together, these fossiliferous beds constitute
the Jones Branch fossil horizon (sensu Stults et al. 2024). One sand lens yielded the Jones Branch
paleofauna discussed herein. Although Dockery & Thompson (2016) stated that no vertebrate fossils
were known from the Catahoula Formation of Mississippi, specimens that they show in their g. 893,
recovered loose in the stream channel and attributed to the Paynes Hammock Limestone, are now known
to have originated from the superjacent Catahoula Formation.
The fossiliferous sand lens of the Jones Branch fossil horizon appears to be somewhat bimodal
in deposition, as very well-rounded quartz (nearly spherical) grains constitute a large portion of the
mineral clasts. Additionally, fossils of larger marine animals occurring in these channel lags, like oyster
valves and dugong ribs, exhibit signs of breakage and heavy abrasion from post mortem transport. The
terrestrial vertebrate fossils are comparatively more pristine, and angular quartz grains (including rose
quartz) are common, indicating primary deposition.
Fig. 2. Lithostratigraphy of eastern Mississippi, USA. A. Stratigraphic section showing the relationships
among the various Oligo-Miocene lithostratigraphic units occurring in eastern Mississippi. B. E-log
from near the fossil site showing the lithostratigraphic units occurring in the study location.
European Journal of Taxonomy 984: 1–131 (2025)
8
Results
Class Chondrichthyes Huxley, 1880
Subclass Euselachii Hay, 1902
Infraclass Elasmobranchii Bonaparte, 1838
Division Selachii Cope, 1871
Superorder Galeomorphi (sensu Nelson, Grande & Wilson 2016)
Suborder Orectoloboidei Applegate, 1974
Order Orectolobiformes Applegate, 1974
Superfamily Orectoloboidea Naylor et al., 2012
Family Brachaeluridae Applegate, 1974
Brachaeluridae gen. et sp. indet.
Fig. 3A–C
Material examined
UNITED STATES OF AMERICA – Mississippi • 1 isolated tooth; Catahoula Formation; SC2013.28.54.
Description
This tooth crown measures 2 mm in height and 1.5 mm in width. The crown consists of a tall, rather
narrow, triangular main cusp anked by a single pair of lateral cusplets. The main cusp is conical with
indistinct mesial and distal cutting edges (Fig. 3C). In labial view, the main cusp is very slightly distally
inclined, and in prole view, it is straight and lingually directed. The labial crown foot is expanded
basally into a convex protuberance (aka apron), and there is a diminutive, medially located, basally
directed protuberance (Fig. 3A). The lateral cusplets are conical, well-separated from the main cusp,
slightly diverging, and located very low on the crown (Fig. 3B). The root is not preserved.
Remarks
Specimen SC2013.28.54 is the only tooth of its kind available to us, but its symmetrical shape indicates
that it represents an anterior tooth le. The specimen is clearly distinct from the teeth of two other
orectolobiform sharks occurring in the Catahoula Formation (see below). The conical main cusp, single
pair of lateral cusplets located low on the crown, and medial protuberance at the labial crown foot are
Fig. 3. Brachaeluridae gen. et sp. indet. (A–C), Chiloscyllium sp. (D–G), and Nebrius sp. (H–M), teeth.
A–C. SC2013.28.54, Brachaeluridae gen. et sp. indet., anterior tooth. A. Labial view. B. Lingual view.
C. Mesial view. D–E. SC2013.28.55, Chiloscyllium sp., anterior tooth. D. Labial view. E. Lingual view.
F–G. SC2013.28.57, Chiloscyllium sp., lateral tooth. F. Labial view. G. Lingual view. H–I. MMNS VP-
6966, Nebrius sp., tooth. H. Distal view. I. Labial view. J–M. MMNS VP-12033, Nebrius sp., tooth.
J. Mesial view. K. Labial view. L. Lingual view. M. Basal view. Scale bars: A–G = 1 mm; H–M = 3 mm.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
9
features occurring on the teeth of Paleogene Brachaeluridae, including Brachaelurus and Eostegostoma
(see Cappetta 2012). The labial protuberance of SC2013.28.54 is not as clearly dened as it is on
teeth of the aforementioned taxa, but the dentition of extant Brachaelurus waddi (Bloch & Schneider,
1801) shows that the protuberance is less distinct on lateral/posterior teeth compared to anterior teeth
(Herman et al. 1992). Additional specimens are necessary to accurately ascertain the identity of this
orectolobiform taxon.
Superfamily Hemiscyllioidea Naylor et al., 2012
Family Hemiscylliidae Gill, 1862
Genus Chiloscyllium Müller & Henle, 1837
Type species
Scyllium plagiosum Bennett, 1830, Recent.
Chiloscyllium sp.
Fig. 3D–G
Material examined
UNITED STATES OF AMERICA – Mississippi • 12 isolated teeth; Catahoula Formation; MMNS
VP-8795 (3 teeth), MMNS VP-12034, SC2013.28.55 (Fig. 3D–E), SC2013.28.56, SC2013.28.57 (Fig.
3F–G), SC2013.28.58 to 28.62.
Description
SC2013.28.55 is the best-preserved specimen and has a crown that measures 2 mm in width and
approximately 2.2 mm in height (Fig. 3D–E). The other teeth are broken and/or ablated but appear to
have had similar dimensions. The crown of SC2013.28.55 consists of a broadly triangular but sharply
tapering main cusp that comprises approximately one-half of the total crown height. The main cusp is
anked by a single pair of short, broad, and slightly diverging lateral cusplets (Fig. 3D). In labial view,
the crown is symmetrical, with an erect main cusp, but in prole view the main cusp is slightly lingually
inclined. Smooth mesial and distal cutting edges occur on the main cusp that extend onto the lateral sides
of the cusplets but do not reach the crown base. The labial face is straight (apico-basally) but slightly
convex (mesio-distally), and the crown foot is formed into a broad, bid protuberance that overhangs
the root. The lingual crown face is convex, and a medial protuberance extends onto the upper surface
of the root. The root is low in prole view and less wide than the crown (Fig. 3E). In basal view, the
root is bilobed, with narrow and widely diverging lobes. The lobes are separated by a deep V-shaped
embayment that opens labially, and a very large foramen occurs at the center of the root. Additional
foramina occur on the upper root surface on each side of the lingual crown protuberance, and another
is located on the lingual-most face of the root. Specimens SC2013.28.59 and SC2013.28.60 (and likely
SC2013.28.56) are less well preserved but appear to have been similar to SC2013.28.55.
Specimens SC2013.28.57 (Fig. 3F–G), SC2013.28.58, and SC2013.28.61 dier from the above
specimens by their lower overall crown height, lower and distally inclined main cusp, and lower and
broader lateral cusplets. Additionally, both mesial and distal cusplets are distally directed (whereas they
are diverging on the teeth described above). SC2013.28.62 is highly ablated but notable for the apparent
lack of lateral cusplets and the uniformly convex labial apron.
Remarks
These Catahoula Formation teeth are like those of fossil species assigned to Chiloscyllium and to extant
Stegostoma Müller & Henle, 1837, and species of both genera have smooth crown enameloid and
typically a pair of large lateral cusplets. However, one conspicuous dierence between the genera is
European Journal of Taxonomy 984: 1–131 (2025)
10
the shape of the teeth, which in extant Stegostoma are all symmetrical, from anterior to posterior les
(Herman et al. 1992; Cappetta 2012). In contrast, teeth of Chiloscyllium exhibit monognathic heterodonty,
with the main cusp becoming lower and more distally inclined towards the commissure (Herman et al.
1992; Noubhani & Cappetta 1997; Cappetta 2012). Adnet et al. (2020) recently erected a new tooth-
based Eocene species of Stegostoma that seemingly contradicts the near homodonty observed in extant
representatives. The teeth of their fossil species are comparable to those of Chiloscyllium, particularly to
Eocene C. meraense Noubhani & Cappetta, 1997, but Adnet et al. (2020) apparently separated the two
genera by the presence or absence of lateral cusplets. In the Eocene Stegostoma species, lateral cusplets
are present even in posterior positions, whereas they are reduced or absent in distally located teeth
of Chiloscyllium (i.e., Noubhani & Cappetta 1997). Treating this particular feature as taxonomically
signicant, the Catahoula Formation specimens are referred to Chiloscyllium due to the combination of
features that include a single pair of lateral cusplets on anterior and lateral teeth, asymmetrical lateral
and posterior teeth, and reduced to absent lateral cusplets on distal lateral and posterior teeth.
The teeth we identify as Chiloscyllium sp. bear similarities to those of Hemiscyllium, but they dier
from the latter by their larger overall size and signicantly larger lateral cusplets, particularly on anterior
teeth (Herman et al. 1992; Cappetta 2012; Adolfssen & Ward 2013; Engelbrecht et al. 2017). The
Catahoula Formation teeth also dier from the supercially similar Eocene taxon Notorhamphoscyllium
Engelbrecht et al., 2017 by having conspicuous mesial and distal cutting edges on the main cusp.
The Chiloscyllium sp. teeth clearly dier from the Brachaeluridae gen. et sp. indet. tooth in our sample
(SC2013.28.54) by their shorter cusp, roughly equal crown height and width dimensions, broader
(typically bid) labial apron, and lateral cusplets occurring much higher on the crown. Teeth of
Catahoula Formation Nebrius sp. are generally wider than high and have ten or more sets of lateral
cusplets that decrease in size distally. Although Chiloscyllium has previously been reported from the
Cretaceous Gulf Coastal Plain in Alabama (Nicholls & Russell 1990; Ciampaglio et al. 2013; Ikejiri
et al. 2013; Ebersole et al. 2024b) and Mississippi (Cicimurri et al. 2014), to our knowledge the Catahoula
Formation specimens represent the rst North American Oligocene record of this genus.
Family Ginglymostomatidae Gill, 1862
Genus Nebrius Rüppell, 1837
Type species
Nebrius ferrugineus Lesson, 1831, Extant.
Nebrius sp.
Fig. 3H–M
Material examined
UNITED STATES OF AMERICA – Mississippi • 8 isolated teeth; Catahoula Formation; MMNS VP-
6966 (Fig. 3H–I), MMNS VP-12033 (Fig. 3J–M), SC2013.28.63 to 28.68.
Description
Teeth are wider (mesio-distally) than they are high, with the largest specimen (SC2013.28.63) measuring
slightly over 6 mm and 5 mm in these dimensions. In labial view, the broadly triangular, low crown bears
a medially located main cusp that is anked by multiple sets of lateral cusplets (Fig. 3K–L). The main
cusp is low, triangular, lingually directed, and may be vertical to distally inclined. Lateral cusplets are
much smaller than the main cusp, and cusplet size decreases towards the crown base. Typically, there are
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
11
more cusplets on the mesial side than on the distal side (Fig. 3I, K). The mesial and distal cutting edges
extend along the lateral cusplets and the main cusp. The labial face is weakly convex mesio-distally, and
there is a conspicuous basally directed protuberance that has a rounded or attened basal margin (Fig.
3I, K). The lingual crown face is convex and bears a medial protuberance that extends lingually onto
the root (Fig. 3L). In prole view, the labial face ranges from sinuous to straight (compare Fig. 3H to
J), and the main cusp apex is distally directed. The crown enameloid is smooth. The root is low, extends
laterally nearly to the crown margin, and is sub-triangular in basal view. A large central foramen occurs
within a deeply convex basal attachment surface (Fig. 3M). Additional foramina are located just below
the crown on the upper surface of the lingual root face.
Remarks
Based on the dentition of extant Nebrius ferrugenius (Lesson, 1831), as illustrated by Herman et al.
(1992), the sample available to us, although limited, indicates that gradient monognathic heterodonty
was developed in the Catahoula Formation Nebrius species. Rather narrow and somewhat symmetrical
teeth are interpreted to represent anterior jaw positions (Fig. 3K), whereas lateral teeth are wider,
have a more distally inclined main cusp, and the longer mesial side bears more cusplets compared to
the distal side (Fig. 3I). Teeth from distal lateral to posterior positions have a diminutive and sharply
distally inclined main cusp, an elongated and highly convex mesial edge with numerous cusplets, and a
comparatively shorter distal edge with signicantly fewer cusplets. Additionally, the labial protuberance
on the teeth in our sample has either a at or a rounded basal margin, a phenomenon we also observed in
the N. ferrugenius dentition, further corroborating the presence of monognathic heterodonty within our
sample of fossil Nebrius sp. teeth.
The Nebrius sp. teeth clearly dier from specimen SC2013.28.54 (Brachaeluridae gen. et sp. indet.)
by their wider crowns, prominent labial basal apron, and numerous lateral cusplets. Unfortunately,
all the specimens in our sample are damaged and/or ablated, and it is dicult to compare them to
ginglymostomatid teeth reported from Oligocene deposits elsewhere. Only a crown fragment referred
to Ginglymostomatidae was reported from the Rupelian Ashley Formation of South Carolina (Cicimurri
et al. 2022), and an incomplete tooth was recovered from the Chattian Chandler Bridge Formation
by Cicimurri & Knight (2009). The latter specimen does not dier appreciably from the Catahoula
Formation teeth. Müller (1999) identied Ginglymostoma delfortriei Daimeries, 1889 from the Oligo-
Miocene Belgrade Formation of North Carolina, but all the specimens shown (pl. 2 gs 2–4) are broken
apically. We concur with Yabumoto & Uyeno (1994) and assign the delfortriei morphology to Nebrius
because the teeth exhibit signicantly more than three sets of lateral cusplets, as opposed to only two or
three on Ginglymostoma (Cicimurri & Knight 2009; Ebersole et al. 2019). Cicimurri & Knight (2009)
tentatively identied their single specimen as N. serra (Leidy, 1877), but the validity of this taxon is
debatable because the stratigraphic and geographic provenance of the original specimen(s) is uncertain.
It may be that the Mississippi and North and South Carolina fossil Nebrius specimens are conspecic,
but larger samples of well-preserved specimens from all these locations are necessary to make this
determination.
Order Lamniformes Berg, 1937
Family Otodontidae Glückman, 1964
Genus Otodus Agassiz, 1843
Subgenus Otodus (Carcharocles) Hannibal & Jordan in Jordan, 1923 (sensu Cappetta 2012)
Type species
Squalus auriculatus de Blainville, 1818, middle Eocene, Belgium.
European Journal of Taxonomy 984: 1–131 (2025)
12
Otodus (Carcharocles) sp.
Fig. 4
Material examined
UNITED STATES OF AMERICA – Mississippi • 1 isolated tooth; Catahoula Formation; MMNS VP-
6608.
Description
The specimen was broken upon recovery but has been repaired in its entirety, and it measures 6.2 cm
in total height and 4.5 cm in width (mesio-distal). The tooth has a broadly triangular main cusp that is
anked by a pair of relatively small lateral cusplets. The main cusp is slightly distally inclined, and its
labial face is at, but its lingual face is convex, and the enameloid is smooth. In prole view, the main
cusp is generally straight but slightly labially curved near the apex. The cutting edges are continuous
along the main cusp and lateral cusplets. The mesial and distal cutting edges on the main cusp are
somewhat concave at the lower half of the crown, but they become convex apically before converging
to form a blunt apex. With respect to the lateral cusplets, the distal cutting edge is elongated and straight
to weakly concave, whereas the mesial edge is very short and convex. The cusplets are rather small with
respect to main cusp size, they occur very low on the crown, and they are dierentiated from the main
cusp by a deep notch (Fig. 4A). All cutting edges are serrated, but serration size and complexity vary
along each cutting edge. Macroscopically, the serrations appear to be regular but under magnication
larger or smaller individual serrae are scattered within lengths of more uniformly sized serrae. The
apical and basal margins of individual serrae are sub-parallel, and serrae are separated from each other
by deep notches. Some individual serrae are subdivided by one or two additional, smaller serrae. On the
lateral cusplets, the serrations on the mesial edge are conspicuously ner than those on the distal edge.
A wide, triangular dental band is located between the lingual crown foot and root (Fig. 4B). The root is
massive, with rather short but robust mesial and distal lobes having rounded margins. The interlobe area
is broadly U-shaped. A prominent lingual boss is perforated by nutritive foramina.
Fig. 4. Otodus (Carcharocles) sp., MMNS VP-6608, upper left tooth. A. Labial view. B. Lingual view.
Scale bar = 3 cm.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
13
Remarks
Specimen MMNS VP-6608 appears to be an upper left tooth, possibly the second anterior, based on the
width and slight distal inclination of the crown, as well as its relatively short root lobes (mesial lobe
narrower and more pointed than the distal lobe) and broad U-shaped interlobe area (see also Gottfried
& Fordyce 2001). Only one Catahoula Formation otodontid tooth is available to us, but the specimen
is comparable to large examples of Otodus (Carcharocles) angustidens (Agassiz, 1835) identied
from Oligocene deposits of Europe (i.e., Baut & Génault 1999; Reinecke et al. 2001, 2005). The
Catahoula tooth diers from those in a sample of small Otodus (Carcharocles) teeth we examined
from the Chattian Chandler Bridge Formation of South Carolina (SC89.240 and SC2006.1). These
Chattian teeth were identied as Carcharocles sp. by Cicimurri & Knight (2009) and as Carcharodon
subauriculatus (Agassiz, 1843) by Purdy et al. (2001). The rather broad but low lateral cusplets are not
as well dierentiated from the main cusp cutting edges compared to the Catahoula Formation tooth, a
condition that is more similar to that of Otodus (Megaselachus) chubutensis (Ameghino, 1906). The
Otodus (Carcharocles) subauriculatus morphotype is synonymous with O. (M.) chubutensis, and in fact
Miocene specimens identied as Carcharodon subauriculatus by Purdy et al. (2001) have been reassigned
to O. (M.) chubutensis (Perez et al. 2018). Although it is possible that the Chandler Bridge Formation
teeth represent a transitional taxon between O. (C.) angustidens and O. (M.) chubutensis, this hypothesis
is dicult to test with the single tooth in our sample. The otodontid taxa O. (C.) aksuaticus (Menner,
1928), O. (C.) auriculatus (de Blainville, 1818), O. (C.) sokolovi (Jaekel, 1895), O. (C.) angustidens,
and O. (M.) chubutensis may represent a single lineage that culminates with Otodus (Megaselachus)
megalodon (Agassiz, 1835) (Applegate & Espinosa-Arrubarrena 1996), but it is also possible that
several otodontid lineages may have been present in the Paleogene (Cappetta 2012). The morphological
criteria used to identify species can be ambiguous, as demonstrated above by the Catahoula Formation
specimen (i.e., “regular” or “irregular” serrations) and within relatively small samples of teeth from one
lithostratigraphic unit. Due to these factors, we herein only identied specimen MMNS VP-6608 to the
generic level.
Family Carchariidae Müller & Henle, 1838
Genus Carcharias Ranesque, 1810
Type species
Carcharias tauras Ranesque, 1810, Extant.
Carcharias cuspidatus (Agassiz, 1843)
Fig. 5A–N
Lamna cuspidata Agassiz, 1843: 290.
Material examined
UNITED STATES OF AMERICA – Mississippi • 240 isolated teeth; Catahoula Formation; MMNS
VP-6626 (168 teeth), MMNS VP-12053 (Fig. 5A–B), MMNS VP-12054 (Fig. 5C–D), MMNS VP-
12055 (Fig. 5M–N), MMNS VP-12056 (Fig. 5E–F), MMNS VP-12057 (Fig. 5K–L), MMNS VP-
12058 (Fig. 5I–J), SC2013.28.272 to 28.283, SC2013.28.284 (Fig. 5G–H), SC2013.28.285 to 28.290,
SC2013.28.292 to 28.328, SC2013.28.329 (10 teeth).
Description
Teeth can attain large sizes, with broken specimens estimated to have been more than 3 cm in total
height. The tooth crown consists of a very large main cusp that is usually anked by lateral cusplets. The
European Journal of Taxonomy 984: 1–131 (2025)
14
main cusp may be mesio-distally narrow, tall, and labio-lingually thick or broadly triangular and labio-
lingually thin. Cutting edges are smooth and may or may not extend to the base of the lateral cusplets.
The labial face is at to weakly convex, whereas the lingual crown face is more strongly convex.
The crown enameloid is smooth. There is typically a single pair of lateral cusplets, although a poorly
developed second cusplet may be present. Cusplets vary from small, narrow, and sharply pointed to
low, very broad, and almost heel-like. Some specimens exhibit a denticulated morphology (Fig. 5K–L).
Root lobes vary in shape and can be narrow and elongated or short and sub-rectangular, and lobes may
be sub-parallel or widely diverging. The interlobe area is U-shaped but varies from deep and narrow to
broad and shallow. A robust lingual protuberance may occur on the lingual root face, which is bisected
Fig. 5. Carcharias cuspidatus (Agassiz, 1843) (A–N), a. Pseudocarcharias sp. (O–R), and Alopias
sp. (S–V), teeth. A–B. MMNS VP-12053, Carcharias cuspidatus, upper anterior tooth. A. Labial view.
B. Lingual view. C–D. MMNS VP-12054, C. cuspidatus, upper right third anterior tooth. C. Labial
view. D. Lingual view. E–F. MMNS VP-12056, C. cuspidatus, ablated tooth. E. Labial view. F. Lingual
view. G–H. SC2013.28.284, C. cuspidatus, upper right lateral tooth. G. Labial view. H. Lingual view.
I–J. MMNS VP-12058, C. cuspidatus, lower right lateral tooth. I. Labial view. J. Lingual view.
K–L. MMNS VP-12057, C. cuspidatus, upper right lateral tooth. K. Labial view. L. Lingual view.
M–N. MMNS VP-12055, C. cuspidatus, lower right anterior tooth. M. Labial view. N. Lingual view.
O–P. SC2013.28.269, a. Pseudocarcharias sp., anterior tooth. O. Labial view. P. Lingual view.
Q–R. SC2013.28.270, a. Pseudocarcharias sp., upper right lateral tooth. Q. Labial view.
R. Lingual view. S–T. MMNS VP-7643, Alopias sp., anterior tooth. S. Labial view. T. Lingual view.
U–V. SC2013.28.271, Alopias sp., lateral tooth. U. Labial view. V. Lingual view. Scale bars: A–P, S–T =
1 cm; Q–R, U–V = 5 mm.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
15
by a narrow and long nutritive groove. Other lingual root surfaces have a more shelf-like appearance but
also bear a conspicuous nutritive groove.
Remarks
Monognathic heterodonty is evident in our sample, with anterior teeth having a narrow main cusp with a
sinuous prole. The mesial and distal cutting edges do not reach the base of the main cusp, the diminutive
cusplets are narrow and pointed, and the root lobes are thin and elongated (Fig. 5A, M). There are
variations in upper anterior tooth shape as, for example, demonstrated between the rather vertical crown
and moderately diverging root lobes of the second upper anterior position (Fig. 5B) and the mesially
curving crown and widely diverging lobes of the third anterior tooth (Fig. 5D). Upper lateral teeth
(Fig. 5G–H, K–L) have a broader and labio-lingually thinner main cusp, the cutting edges are complete,
and the lateral cusplets are low but very broad. Additionally, well-preserved specimens demonstrate that
the root lobes are shorter, sub-rectangular and more divergent. With respect to dignathic heterodonty, the
crowns of lower anterior teeth have a strong lingual curvature compared to those of upper anterior teeth,
and the root lobes of upper anterior teeth are thicker, shorter, and more divergent compared to those of
lower teeth (compare Fig. 5B to N). Additionally, upper lateral teeth are distally inclined, but those of
the lower jaw are nearly vertical (compare Fig. 5G to I). Variations in overall tooth size within each tooth
le are indicative of ontogenetic heterodonty, where smaller teeth (of juvenile individuals) are simply
more gracile versions of larger (adult) teeth. A similar phenomenon was reported for Mennerotodus by
Cicimurri et al. (2020).
The teeth described above compare favorably to those of Carcharias cuspidatus, a species commonly
reported from the Oligo-Miocene of North America and Europe (Baut & Génault 1999; Müller 1999;
Purdy et al. 2001; Cappetta 2012; Reinecke et al. 2014). Over the past few decades, this species has
variably been assigned to Carcharias (i.e., Purdy et al. 2001) and Araloselachus (see Cappetta 2012),
with the most recent classication placing it within the former (Hovestadt 2020, 2022). Cappetta (2012)
considered Araloselachus as distinct from Carcharias and other similar taxa, because teeth have smooth
enameloid, anterior teeth have a less sigmoidal prole and “small and simple” (Cappetta 2012: 191) lateral
cusplets, and lateral teeth have broad but low (sometimes) “pectinate” lateral cusplets. However, the
crowns can be more-or-less sigmoidal depending on tooth position within a given jaw (i.e., upper versus
lower, rst anterior versus third anterior). Additionally, the presence or absence of crown ornamentation
on teeth can be variable among individuals within a population of a given species (Purdy et al. 2001;
Cicimurri et al. 2020). Furthermore, the “pectinate” lateral cusplets of lateral teeth, visible on some
Catahoula Formation specimens (i.e., MMNS VP-12057), were also noted by Cicimurri et al. (2020)
on Eocene Mennerotodus teeth. Purdy et al. (2001) provided some additional tooth characteristics that
might prove useful in dierentiating C. cuspidatus from C. taurus (Ranesque, 1810), but the available
sample does not allow us to test those criteria. Our observations regarding dignathic heterodonty are
consistent with the work of Hovestadt (2020), who presented a reconstructed dentition of C. cuspidatus
based on an articulated skeleton (pl. 7 gs 1–22), and familial assignment to Carchariidae is warranted.
Family Pseudocarchariidae Taylor et al., 1983
Genus Pseudocarcharias Cadenat, 1963
Type species
Carcharias komoharai Matsubara, 1936, Extant.
European Journal of Taxonomy 984: 1–131 (2025)
16
a. Pseudocarcharias sp.
Fig. 5O–R
Material examined
UNITED STATES OF AMERICA – Mississippi • 2 isolated teeth; Catahoula Formation; SC2013.28.269
(Fig. 5O–P), SC2013.28.270 (Fig. 5Q–R).
Description
SC2013.28.269 measures 23 mm in total height and 10 mm in width. It bears a tall and rather erect main
cusp. Although the cusp is slightly distally inclined, it has a distinct mesial curvature that is the result of
the concave mesial cutting edge intersecting apically with the convex distal cutting edge. Both cutting
edges are smooth and sharp, and they extend onto mesial and distal shoulders. The transition from main
cusp to lateral shoulder is highly curved but not angular. The shoulders are very low and slightly convex
at their distal ends, and the mesial shoulder is longer than the distal one (Fig. 5O). The labial crown
face is very weakly convex, but the lingual face is very convex, and both faces are smooth. The root is
bilobate with strongly diverging lobes that are thin, elongated, and have a pointed extremity (the distal
lobe is damaged). The interlobe area is U-shaped. A thin and shelf-like lingual boss bears a very short
nutritive groove (Fig. 5P).
SC2013.28.270 is a smaller tooth measuring 7 mm in total height and 7 mm in width, and having a
distally inclined and curved main cusp. The smooth and sharp cutting edges extend onto elongated
mesial and distal shoulders. The mesial shoulder is not strongly distinguished from the main cusp,
whereas the transition from the distal cutting edge to the distal shoulder is a deeply concave line. The
shoulders are low, elongated (slightly longer mesially), and their distal ends are somewhat pointed
(Fig. 5Q). The labial crown face is weakly convex, the lingual face is strongly convex, and the enameloid
is smooth. The strongly bilobate root bears a very short lingual nutritive groove (Fig. 5S). The root lobes
are very highly diverging, relatively short, thin, and have pointed extremities. The interlobe area is
V-shaped.
Remarks
Although dierent from each other in terms of overall shape, the features shared by SC2013.28.269
and SC2013.28.270 lead us to conclude that they represent the same species. Specimen SC2013.28.269
(Fig. 5O–P) is reminiscent of a more anteriorly located tooth, whereas SC2013.28.270 (Fig. 5Q–R)
is from a lateral jaw position. The smooth cutting edges, curved transition from main cusp to lateral
shoulder, and lack of lateral cusplets distinguish these teeth from those of Otodontidae and Carchariidae
occurring within the Catahoula Formation.
The two specimens described above are perhaps the most enigmatic within the Catahoula Formation
sh assemblage. They are dierentiated from comparably-sized teeth of Carcharias cuspidatus
(see above) by their lack of cusplets and continuous transition from main cusp to lateral shoulders.
Specimens SC2013.28.269 and SC2013.28.270 are similar to teeth of Mitsukurinidae, two species of
which, Mitsukurina lineata (Probst, 1879) and Woellsteinia oligocaena Reinecke et al., 2001, have been
reported from Oligocene strata elsewhere (Reinecke et al. 2005). However, the Catahoula Formation
teeth lack the longitudinal ridges on the lingual crown face that characterizes those taxa, and instead
have smooth crown enameloid. Specimens SC2013.28.269 and SC2013.28.270 are very weakly
cuspidate (particularly the former specimen) and are comparable to teeth within the jaws of male and
female Pseudocarcharias kamoharai (Matsubara, 1936) as shown by Pollerspöck & Straube (2020: g.
10), and they bear similarities to Pseudocarcharias teeth identied by Cigala Fulgosi (1992) from the
Middle Miocene (Serravallian) of Italy. The very weakly cuspidate appearance of the lateral shoulders
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
17
on the Catahoula Formation specimens contrasts with the condition of teeth of the Early Miocene
(Burdigalian) P. rigida (Probst, 1879), which has distinctive lateral cusplets on upper and lower lateral
teeth (Bracher & Unger 2007). To our knowledge, Pseudocarcharias does not have a pre-Miocene fossil
record (also Cappetta 2012), and the Catahoula Formation teeth would represent a signicant temporal
range extension back to the “middle” Oligocene. Additional specimens, especially distinctive anterior
teeth, are necessary to corroborate the identity of these two teeth.
Family Alopiidae Bonaparte, 1840a
Genus Alopias Ranesque, 1810
Type species
Alopias macrourus Ranesque, 1810, Extant.
Alopias sp.
Fig. 5S–V
Material examined
UNITED STATES OF AMERICA – Mississippi • 2 isolated teeth; Catahoula Formation; MMNS VP-
7643 (Fig. 5S–T), SC2013.28.271 (Fig. 5U–V).
Description
Specimen MMNS VP-7643 has a rather low but broadly triangular main cusp that is weakly distally
inclined. In prole the crown is at. The labial face is convex along the margins but concave medially,
and there is a thickening at the crown foot. The lingual face is strongly and uniformly convex. Both
crown faces have smooth enameloid. The mesial cutting edge is relatively straight, but the distal edge
is weakly convex. Both cutting edges are smooth and extend basally onto short lateral shoulders. The
mesial shoulder is more elongated but not well-dierentiated compared to the distal heel. The bilobate
root has rather short and highly diverging lobes with rounded extremities. The interlobe area is broadly
U-shaped.
Tooth SC2013.28.271 has a broad and very distally inclined cusp. The elongated mesial cutting edge is
weakly convex apically and extends basally onto an elongated heel. The distal cutting edge is straight
but transitions basally through a curved 90° angle onto a short distal heel. The cutting edges are smooth.
The labial crown face is weakly convex and has a thickened crown foot. The distal face is more strongly
convex, and the crown enameloid on both faces is smooth. The root is bilobate with short but highly
diverging lobes that have rounded extremities. There is a conspicuous nutritive pore on a small lingual
boss.
Remarks
Although dierent from each other, MMNS VP-7643 (Fig. 5S–T) and SC2013.28.271 (Fig. 5U–V)
both have broadly triangular crowns, smooth cutting edges that extend onto lateral shoulders, and root
lobes with rounded extremities. These shared features lead us to conclude that they represent the same
taxon and allow us to distinguish them from coeval Otodontidae and Carchariidae teeth in the Catahoula
Formation. Additionally, these two teeth dier from a. Pseudocarcharias sp. described above by having
shorter but much broader crowns, non-cuspidate lateral shoulders, roots apparently lacking a nutritive
groove, and lobes with rounded extremities.
European Journal of Taxonomy 984: 1–131 (2025)
18
Specimens MMNS VP-7643 and SC2013.28.271 are comparable to teeth in an associated tooth set of
extant Alopias vulpinus (Bonnaterre, 1788) (SC2015.30.1) and within the jaws of an A. superciliosus
Lowe, 1841 (SC202.53.12) that we examined. Tooth MMNS VP-7643 appears to represent an anterior
jaw position, as it has a rather erect crown with only slight distal inclination (Fig. 5S–T). In contrast, the
lower cusp height and greater distal inclination of SC2013.28.271 indicate that it is from a more lateral
tooth le (Fig. 5U–V). Neither specimen exhibits a nutritive groove, but this feature is not developed on
some anterior teeth in SC2015.30.1 (A. vulpinus). Additionally, the root of both specimens is abraded,
and it is possible that these structures are simply not preserved. Teeth identied as Alopias a. vulpinus
in the German Chattian (Reinecke et al. 2005: pls 21–22) appear to be more broad-based than the two
Catahoula Formation specimens reported herein. The Catahoula Formation Alopias specimens have a
much wider crown compared to the teeth of A. exigua (Probst, 1879), which have been reported from
the Oligocene of Europe (i.e., Reinecke et al. 2001, 2005).
We note here the taxon Alopias latidens alabamensis White, 1956 that was based on teeth derived from
upper Eocene (Priabonian) deposits in Alabama (Gulf Coastal Plain of the USA). Ebersole et al. (2019)
determined that White’s taxon was a composite based on multiple taxa, with one being identied as
Negaprion gilmorei (Leriche, 1942). Within the same volume, White (1956) erected the subspecies
Alopias latidens carolinensis based on teeth derived from “phosphates” in South Carolina. Interestingly,
White’s gured holotype (White 1956: pl. 11 g. 8) is quite similar to specimen SC2013.28.271, and one
might consider that the Catahoula Formation and South Carolina material are conspecic. However, the
usage of Alopias latidens carolinensis for the Catahoula teeth is problematic because the type locality
and precise stratigraphic occurrence and age of White’s syntypes are unknown, and material from the
“phosphates” in South Carolina can range in age from the Eocene to Pliocene (Cicimurri et al. 2022).
We refrain from identifying the two teeth in our Catahoula Formation sample to species until a greater
number of specimens are available for study.
Order Carcharhiniformes Compagno, 1973
Family Hemigaleidae Hasse, 1878
Genus Hemipristis Agassiz, 1835
Type species
Hemipristis serra Agassiz, 1835, Miocene, Germany.
Hemipristis intermedia sp. nov.
urn:lsid:zoobank.org:act:25CF2AFD-3892-43EC-DE9878B39014
Fig. 6
Diagnosis
Upper lateral teeth are the most common tooth morphology represented, and because they are more
diagnostic than the lower teeth, they are utilized herein to diagnose the species. Upper lateral teeth
measure up to 2.5 cm in width (mesio-distal) and 2 cm in height (apico-basal). These teeth have a broad,
triangular crown and distally directed main cusp. The mesial cutting edge may be smooth or bear up
to ten denticles and the distal cutting edge up to 12 denticles, with denticles on both edges increasing
in size towards the apex. A smooth-edged cusp constitutes the apical 30%–40% of the crown. Of the
fossil Hemipristis species we consider valid, the upper lateral teeth of H. intermedia sp. nov. dier from
those of the Eocene H. curvatus Dames, 1883 by attaining larger overall sizes (2.5 cm wide by 2.2 cm
high for H. intermedia vs 1.5 cm and 1.1 cm, respectively for H. curvatus), by having more mesial and
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
19
distal denticles (up to four and eight, respectively for H. curvatus, and up to 10 and 11, respectively,
for H. intermedia), and by having mesial denticles that extend higher on the crown (two-thirds the
crown height vs. one-half the crown height on H. curvatus). Hemipristis intermedia sp. nov. upper
lateral teeth dier from those of the Miocene to Early Pleistocene H. serra Agassiz, 1835 by attaining
smaller overall sizes (3.7 cm wide and 3.6 cm height for H. serra), by having fewer distal denticles
(up to 20 have been observed on H. serra), and by having denticles that do not extent as close to the
apex, resulting in a cusp that represents more than 20% of the crown height (as opposed to 10% in
H. serra). These teeth are dierentiated from those of the Rupelian H. tanakai Tomita, Yabumoto &
Kuga, 2023 by having more than ve mesial denticles (the maximum number reported for H. tanakai),
and the apical-most mesial and distal denticles are of nearly equal height on the crown (whereas the distal
denticle is generally higher in H. tanakai). Finally, the upper lateral teeth of Hemipristis intermedia sp.
nov. dier from those of the extant H. elongata (Klunzinger, 1871) by being mesio-distally wider, by
having more conspicuous denticles, and by having a more convex upper one-half of the mesial crown
edge. The number of tooth denticles of Hemipristis intermedia is greater than the maximum occurring
on H. curvatus teeth but less than the maximum number known for the Miocene to Early Pleistocene H.
serra Agassiz, 1835. The proportion of cusp to total crown height is less than in H. curvatus but greater
than in H. serra. The recently named H. tanakai (Tomita et al. 2023) is considered herein as a nomen
dubium (see below), but the tooth size of that taxon overlaps with those of H. serra and H. intermedia.
Additionally, only ve mesial denticles occur in H. tanakai and the mesial denticles extend closer to the
crown apex compared to the distal edge.
Etymology
The species name refers to the transitional tooth morphology between the Eocene Hemipristis curvatus
and the Miocene to Early Pleistocene H. serra.
Material examined
Holotype
UNITED STATES OF AMERICA – Mississippi • upper left lateral tooth; Catahoula Formation;
SC2013.28.73 (Fig. 6PP–RR).
Paratypes
UNITED STATES OF AMERICA – Mississippi • upper left anterior tooth; Catahoula Formation;
MMNS VP-12037 (Fig. 6G–I) • lower left anterior tooth; Catahoula Formation; SC2013.28.80
(Fig. 6P–R) • lower right lateral tooth; Catahoula Formation; MMNS VP-12036 (Fig. 6D–F).
Other material
UNITED STATES OF AMERICA – Mississippi • 189 isolated teeth; Catahoula Formation; MMNS
VP-464 (2 teeth), MMNS VP-6625 (114 teeth), MMNS VP-6625.1 (Fig. 6HH–JJ), MMNS VP-7243
(7 teeth), MMNS VP-7604 (Fig. 6MM–OO), MMNS VP-7691 (9 teeth), MMNS VP-8745, MMNS
VP-12035 (Fig. 6A–C), MMNS VP-12038 (Fig. 6J–L), MMNS VP-12039 (Fig. 6M–O), MMNS VP-
12040 (Fig. 6S–U), MMNS VP-12041, MMNS VP-12042 (Fig. 6V–X), MMNS VP-12043 (Fig. 6Y–
AA), MMNS VP-12044 (Fig. 6BB–CC), MMNS VP-12045 (Fig. 6DD–EE), MMNS VP-12046 (Fig.
6FF–GG), SC2013.28.69 to 28.72, SC2013.28.74 to 28.79, SC2013.28.81 to 28.89, SC2013.28.90
(Fig. 6KK–LL), SC2013.28.91 to 28.101, SC2013.28.102 (10 teeth), SC2013.28.103 (Fig. 6SS–TT),
SC2013.28.104 (Fig. 6UU–VV), MMNS VP-7604 (Fig. 6MM–OO).
Stratum typicum
Shelly, argillaceous sand of the Jones Branch fossil horizon, lower Catahoula Formation, Chattian Stage
(horizon no longer accessible).
European Journal of Taxonomy 984: 1–131 (2025)
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Locus typicus
Site MS.77.011, Jones Branch, tributary owing into the Chickasawhay River, south of Waynesboro,
Wayne County, Mississippi, USA.
Description
Several tooth morphologies are present, including specimens with a triangular, broad-based but apically
narrow, slightly distally inclined crown. In prole view (Fig.6C, R, U), the crown on these teeth is at
to weakly sigmoidal, and the labial face is weakly convex, but the lingual face is strongly convex. The
crown enameloid is smooth. In prole view, the mesial cutting edge is straight, and in labial/lingual
view, it may be straight or concave basally but convex apically. The distal cutting edge is straight basally
but overall exhibits a convex appearance due to the distally inclined cusp. The degree of curvature on
these edges varies slightly. The mesial edge may be smooth along its entirety or bear up to nine denticles
along its lower one- to two-thirds (compare Fig. 6B, E, H). These denticles are apically directed and
decrease in size basally, but they do not reach the cusp apex and do not extend to the crown base. The
distal edge bears up to nine denticles that decrease in size basally. These denticles do not reach the apex
but can extend to the crown foot. The denticles are not serrated. The uppermost one-third of the crown
is developed into a triangular cusp that varies slightly in width and degree of distal inclination (compare
Fig. 6D to G). The mesial and distal cutting edges of the main cusp are smooth. The root is weakly
bilobate with very short and diverging lobes that are separated by a narrow and shallow U-shaped
interlobe area. A robust lingual boss (i.e., Fig. 6F) is bisected by a long, shallow but wide nutritive
groove.
Other specimens are similar to those described above but have a broader crown that is more strongly
distally curved. This broad-based and distally curved morphology is considered diagnostic of the species
and a representative specimen was chosen as the holotype (Fig. 6PP–RR). The largest tooth of this type
measures 2.5 cm wide and 2 cm in total height. In prole view, the crowns of these teeth are labially
curved and labio-lingually thin. The crown enameloid is smooth. The mesial edge is elongated and can
be sinuous to uniformly convex (compare Fig. 6Y to 6DD), whereas the distal edge is uniformly concave
Fig. 6 (page 21). Hemipristis intermedia sp. nov., teeth. A–C. MMNS VP-12035, lower left lateral tooth.
A. Labial view. B. Lingual view. C. Mesial view. D–F. MMNS VP-12036 (paratype), lower left lateral
tooth. D. Labial view. E. Lingual view. F. Mesial view. G–I. MMNS VP-12037 (paratype), upper left
anterior tooth. G. Labial view. H. Lingual view. I. Mesial view. J–L. MMNS VP-12038, lower right
anterolateral tooth. J. Labial view. K. Lingual view. L. Mesial view. M–O. MMNS VP-12039, lower
right anterior tooth. M. Labial view. N. Lingual view. O. Mesial view. P–R. SC2013.28.80 (paratype),
lower left anterior tooth. P. Labial view. Q. Lingual view. R. Mesial view. S–U. MMNS VP-12040,
upper left lateral tooth. S. Labial view. T. Lingual view. U. Mesial view. V–X. MMNS VP-12042,
upper left lateral tooth. V. Labial view. W. Lingual view. X. Mesial view. Y–AA. MMNS VP-12043,
upper right lateral tooth. Y. Labial view. Z. Lingual view. AA. Mesial view. BB–CC. MMNS VP-
12044, upper left lateral tooth. BB. Labial view. CC. Lingual view. DD–EE. MMNS VP-12045, upper
left lateral tooth. DD. Labial view. EE. Lingual view. FF–GG. MMNS VP-12046, upper left lateral
tooth. FF. Labial view. GG. Lingual view. HH–JJ. MMNS VP-6625, lower left symphyseal tooth.
HH. Labial view. II. Lingual view. JJ. Mesial view. KK–LL. SC2013.28.90, upper right lateral tooth.
KK. Labial view. LL. Lingual view. MM–OO. MMNS VP-7604, juvenile lower left anterior tooth.
MM. Labial view. NN. Lingual view. OO. Mesial view. PP–RR. SC2013.28.73 (holotype), upper right
lateral tooth. PP. Labial view. QQ. Lingual view. RR. Mesial view. SS–TT. SC2013.28.103, juvenile
upper left postero-lateral tooth. SS. Labial view. TT. Lingual view. UU–VV. SC2013.28.104, juvenile
upper left lateral tooth. UU. Labial view. VV. Lingual view. Scale bars: A–U, HH–JJ = 1 cm; MM–OO =
2 mm; V–GG, KK–LL, PP–QQ = 5 mm; RR–UU = 1 mm.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
21
along its length (i.e., Fig. 6T). The degree of curvature of the mesial and distal edges is variable. The
mesial edge may be smooth, but it is more typically denticulated, often with 5–6 denticles, but up to
ten may be present (compare Fig. 6BB, FF, PP, S). These denticles are usually medially located on the
edge, but they may only occur along the lower one-third or extend up to two-thirds of the crown height.
Denticles are apically directed but decrease in size basally. The distal edge often bears eight denticles,
but up to 11 can occur (compare Fig. 6DD to T). Denticles are apically directed but decrease in size
basally, and they extend to the crown foot. Although the distal denticles often extend higher onto the
crown compared to the mesial denticles, the mesial denticles sometimes extend beyond the height of the
distal ones (compare Fig. 6EE to T). The apical portion of the crown is developed into a triangular cusp
that is distally inclined to varying degrees. The mesial and distal cutting edges are smooth. The root is
bilobate, with very wide but short sub-rectangular lobes. These are separated by a narrow U-shaped or
V-shaped interlobe area. A low lingual boss (Fig. 6AA) is bisected by a long, shallow, and wide nutritive
groove.
European Journal of Taxonomy 984: 1–131 (2025)
22
Some specimens are quite distinct from both aforementioned morphotypes, as they are very narrow
mesio-distally and have a tall crown (Fig. 6HH). In prole view, the crown may be weakly sinuous,
with strong lingual curvature and slight labial curvature of the crown faces (Fig. 6JJ). The labial crown
face is moderately convex and the lingual face very convex, which results in a somewhat conical crown.
The crown may lack or have apical cutting edges, and no denticles are developed. The root is narrow,
weakly bilobate, and has a robust lingual boss bearing a conspicuous nutritive groove. A more common
morphology includes teeth with a wider crown that is denticulated. In prole view, the crown is highly
lingually curved, and the labial face is convex basally but atter apically (Fig. 6L, R). The lingual face
is very convex, and crown enameloid is smooth on all specimens. The mesial side of the tooth may be
rounded or bear a cutting edge that does not extend to the crown foot (Fig. 6JJ). Relatively small and
needle-like denticles can occur along the lower one-fourth of the mesial edge, of which up to three have
been observed (Fig. 6Q). The distal edge usually bears a smooth cutting edge, which does not reach
the crown foot. Two to four small and needle-like denticles occur at the lower one-third of the edge
(Fig. 6M, P). The denticles on both sides of the crown are widely separated from each other and may
be medially curved. The cutting edges are always smooth and may reach the level of the denticles. The
denticle-free portion of the crown is a narrow and triangular cusp that is comparatively larger than those
of previously described teeth. The root is bilobate with relatively short, diverging lobes, and the mesial
lobe is more elongated and narrower than the distal lobe (Fig. 6H, Q). A robust lingual boss (Fig. 6O, R,
JJ) is bisected by a deep but narrow nutritive groove.
Specimens SC2013.28.103 (Fig. 6SS–TT) and SC2013.28.104 (Fig. 6UU–VV) are diminutive teeth that
are similar to each other. Both are broad-based and sub-triangular in labial view, with SC2013.28.103
measuring 2 mm in width and SC2013.28.104 just over 3 mm in width as preserved. Both specimens
have an elongated and convex mesial cutting edge, and a much shorter (and smooth) distal cutting
edge that intersect apically to form a rather small and distally inclined cusp. Although the mesial edge
of SC2013.28.104 is smooth, that of SC2013.28.103 bears a diminutive denticle medially (compare
Fig. 6VV to TT). Each specimen has an oblique distal heel that bears four triangular denticles that
decrease in size basally (Fig. 6SS, UU). Overall, the crown of both specimens is rather straight, with
the labial face being relatively at and the lingual face convex. The crown foot of SC2013.28.104 is
not preserved, but that of SC2013.28.103 is thickened and slightly overhangs the root. The root of
SC2013.28.103 is higher on the lingual side than on the labial side. The root lobes are very short, sub-
rectangular, highly divergent, and separated by a very narrow U-shaped interlobe area. The lingual
attachment surface is bisected by a conspicuous nutritive groove.
Specimens SC2013.28.105, MMNS VP-7604, and MMNS VP-8745 are diminutive teeth of comparable
morphology. The crowns measure 2.5 mm in width and 4 mm in height. Much of the crown is comprised
of the main cusp, which is broad basally but rather needle-like apically. The conical cusp may lack
cutting edges (Fig. 6OO) or have mesial and distal cutting edges that are sharp, smooth, and extend to
the base of the main cusp. Although the cusp is somewhat distally inclined, the mesial edge is concave
and the distal edge is convex, which results in an unusual mesially directed cusp apex (Fig. 6NN).
The crown foot at the mesial and distal sides are formed into very short shoulders that each bear two
denticles that decrease in size basally (Fig. 6MM). The labial crown foot is very convex and there is a
shallow but broad U-shaped embayment. The labial and lingual faces are smooth and convex.
Remarks
The tooth morphology of extant Hemipristis elongata (Klunzinger, 1871) is quite variable, and the teeth
of the extinct H. curvatus Dames, 1883 and H. serra Agassiz, 1835 exhibit similar variation. These
taxa, as well as the Catahoula Formation Hemipristis, exhibit monognathic and dignathic heterodonty.
Ontogenetic heterodonty is also evident, as small teeth in our sample are similar to a tooth that Cicimurri
& Knight (2009: g. 5j) recovered from the Chattian Chandler Bridge Formation of South Carolina.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
23
That specimen lacks mesial serrations and was identied as a juvenile upper tooth of Hemipristis. Their
interpretation is consistent with our evaluation of the Catahoula Formation Hemipristis sample, where
upper teeth under 7 mm in width lack mesial serration. Specimens SC2013.28.103, SC2013.28.105,
MMNS VP-7604, and MMNS VP-8745 are supercially like Paragaleus teeth, but our evaluation of
four jaws of extant Hemipristis elongata (SC84.177.1, SC86.52.1, SC2020.53.9, MSC 42627) leads us to
conclude that they are teeth of very small individuals of H. intermedia sp. nov. Specimen SC2013.28.103
(Fig. 6SS–TT) is comparable to teeth in the postero-lateral les of H. elongata, whereas SC2013.28.105
(Fig. 6UU–VV), MMNS VP-7604 (Fig. 6MM–OO), and MMNS VP-8745 are virtually identical to
teeth in the lower anterior les.
Upper anterior teeth in the Catahoula Formation sample are identied by their triangular and rather
weakly asymmetrical crown, whereas upper lateral teeth are broadly triangular with a conspicuous
distally hooked appearance (compare Fig. 6G to S). Within lateral les, the amount of curvature of
the mesial and distal edges, and the degree of distal cusp inclination increase towards the commissure
(compare Fig. 6PP to FF). Specimens believed to be lower symphyseal or parasymphyseal (i.e.,
Fig. 6HH–JJ) teeth are very narrow with a roughly conical crown that lacks denticles and sometimes
cutting edges. Lower anterior teeth are much narrower and bear signicantly fewer denticles compared
to upper anteriors, and the cusp constitutes a comparatively larger portion of the crown (Fig. 6J, P).
The root of lower anterior teeth also has a more robust lingual boss compared to the upper teeth. Teeth
from lateral positions are broader, have elongated cutting edges that reach the level of the mesial and
distal denticles, and have up to ve mesial and at least seven distal denticles. Based on our evaluation
of extant H. elongata jaws (i.e., SC84.177.1, SC86.53.1), upper anterior teeth of H. intermedia sp. nov.
are distinguished from lower lateral teeth by the greater number of mesial and distal denticles and the
comparatively smaller proportion of main cusp to crown height (compare Fig. 6G to E). We chose an
upper lateral tooth as the holotype specimen (Fig. 6PP–RR) for the new species because, among the
various fossil Hemipristis that have been named, this morphology is often the most common and easily
identied.
The fossil record of Hemipristis extends back to the middle Eocene, with specimens of the globally
widespread H. curvatus occurring as early as the Lutetian (NP15) (Ebersole et al. 2019). The species
is well known from North America (i.e., White 1956; Westgate 1984; Parmley & Cicimurri 2003;
Cicimurri & Knight 2019; Perez 2022) and Africa (i.e., Adnet et al. 2010, 2020; Underwood et al.
2011), with rare records from Asia (Tanaka et al. 2006; Tomita et al. 2023) and possibly Europe (Priem
1912; Ciobanu 1994). Hemipristis serra ranges from the Miocene to Early Pleistocene and was nearly
globally distributed (Cappetta 2012). Hemipristis has also been reported from various Oligocene sites
in the USA (Cicimurri & Knight 2009; Ebersole et al. 2021; Cicimurri et al. 2022) and Asia (Adnet
et al. 2007), with specimens having been tentatively assigned to H. serra or altogether not speciated.
Although Chandler et al. (2006) indicated that there was no evidence for the existence of Paleogene and
Neogene species of Hemipristis other than H. curvatus and H. serra, Adnet et al. (2007) and Ebersole
et al. (2021) suggested that Oligocene teeth represent a transitional species between the two.
Although the gross morphology of Hemipristis teeth has remained stable, even to the present day, large
samples of H. curvatus teeth from the middle Eocene of Alabama (MSC collection), Bartonian of South
Carolina (SC2022.27) and Georgia (SC2004.34, SC2013.44), along with samples of H. serra from the
Middle Miocene (Langhian) of North Carolina (contained within accession SC98.46) and Gelasian
(Early Pleistocene) of South Carolina (accessions SC89.240, SC2006.1), and jaws of extant H. elongata
reveal signicant dierences among the various taxa. With respect to H. curvatus, H. intermedia sp. nov.
attains a larger overall size (2.5 cm wide by 2.2 cm high vs 1.5 cm and 1.1 cm), and the latter species
consistently has more extensively denticulated mesial and distal edges. Whereas the upper lateral teeth
of H. curvatus exhibit fewer than four mesial and up to eight distal denticles, the teeth of H. intermedia
European Journal of Taxonomy 984: 1–131 (2025)
24
have up to 10 mesial and 11 distal denticles. Additionally, the mesial denticles of H. curvatus are
limited to the lower one-half of the crown, whereas they extend up to two-thirds of the crown height of
H. intermedia. The cusp of H. curvatus teeth constitutes a larger proportion of the crown compared to
H. intermedia. Variations in the number of mesial and distal denticles in H. curvatus and H. intermedia
were also observed among the three jaws of H. elongatus, but the maximum number of denticles present
and their distributions along the mesial and distal edges are taxonomically signicant.
Hemipristis serra upper lateral teeth attain a signicantly larger size than those of H. intermedia
sp. nov., with the largest specimen available to us measuring 3.7 cm wide and 3.6 cm in height. In
contrast, the largest tooth of H. intermedia sp. nov. in our sample measures only 2.5 cm and 2.2 cm in
these dimensions, respectively. Additionally, the mesial and distal edges of H. serra teeth have a greater
number of denticles, with at least 13 occurring on the distal side but more than 20 are common. On the
mesial edge, the denticles are largest and most conspicuous along the upper one-half of the crown, but
basally the edge appears more regularly serrated (serration/denticulation also consistently reaches the
base of the edge). The denticles on H. serra teeth also extend closer to the apex, and the cusp comprises
a very small portion of the crown compared to in H. intermedia. On the former, the cusp can represent
as little as 10% of the total tooth height, whereas on the latter it represents at least 20%. Furthermore,
small teeth of H. serra are as regularly serrated/denticulated as large teeth, whereas in H. intermedia
these features are generally more extensive on large specimens.
Upper anterior teeth of each of the Paleogene and Neogene taxa are similar in gross morphology but
can be separated based on the combination of maximum tooth size, degree of mesial denticulation and
location of mesial denticles, degree of denticulation of the distal edge, and size of the cusp with respect
to overall tooth size. The overall trend through time is an increase in maximum tooth size and number
of mesial and distal denticles and a decrease in cusp size (in relation to total crown size). We found that
the morphologies of lower anterior teeth of the Paleogene and Neogene taxa overlap and are largely
dierentiable by crown size and robustness. These teeth are not considered to be taxonomically useful
for species determination.
For completeness, we also evaluated the teeth of extant H. elongata. All four H. elongata jaws we
examined are of the same size and have similar tooth sizes, and none of the upper lateral teeth approach
the largest H. curvatus in our sample (1 cm wide and 0.9 cm high vs 1.5 cm and 1.1 cm in these
dimensions), let alone the largest H. intermedia sp. nov. tooth. In general, the upper lateral teeth of
H. elongata are narrower and the mesial denticles (up to ten) are much less conspicuous compared to
teeth of the extinct species. Additionally, the lower half of the tooth is the most convex, whereas it is
most convex along the upper one-half on the fossil teeth. Interestingly, the cusp of H. elongata teeth
constitutes slightly more than 20% of the total tooth height.
The Catahoula Formation Hemipristis teeth were compared to Oligocene specimens from the southeastern
Atlantic Coastal Plain and Gulf Coastal Plain of the USA, including material from the Glendon Limestone
Member of the Byram Formation of Alabama (Rupelian Stage, circa 30 Ma, NP23), the Old Church
Formation of Virginia (Rupelian, roughly 29 Ma), the Ashley Formation of South Carolina (Rupelian,
approximately 28.5 Ma), and the Chandler Bridge Formation of South Carolina (Chattian Stage, about
24.5 Ma). The Glendon Limestone Member specimen, documented by Ebersole et al. (2021), is a lower
anterior tooth that is taxonomically uninformative beyond the generic level. Specimens from the Ashley
Formation were identied as H. serra by Müller (1999) and Cicimurri et al. (2022). The specimens
shown by Müller (1999: pl. 8 g. 9) and Cicimurri et al. (2022: g. 5a) are both comparable in size to
the Catahoula Formation teeth, and the mesial edges are more extensively denticulated compared to in
H. curvatus. Visually, the proportion of cusp to tooth height appears to be greater than that of H. serra.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
25
We examined ve teeth from the Old Church Formation of Virginia that are included within accession
SC2020.43, as well as illustrations of four specimens provided by Müller (1999: pl. 8 gs 12–15). In
general, the teeth are similar to those of the Catahoula Formation with respect to the number of denticles
and the size of the cusp compared to overall tooth size. However, one specimen shown by Müller (1999:
pl. 8 g. 12) exhibits a large number of mesial/distal denticles and a relatively small cusp, features more
consistent with H. serra. Ten teeth from the Chandler Bridge Formation contained within SC2005.2 were
examined, as were two specimens identied as H. serra by Cicimurri & Knight (2009). The Chandler
Bridge Formation sample is variable and contains specimens that are similar to the Catahoula Formation
teeth, as well as specimens that are comparable to H. serra (i.e., Cicimurri & Knight 2009: g. 5i).
The Catahoula Formation Hemipristis teeth are comparable to Hemipristis specimens from the Ashley
Formation and, for the most part, the Old Church Formation. The Ashley and Old Church formations
are slightly older than the Rupelian/Chattian Stage boundary, whereas the Catahoula Formation teeth are
slightly younger than that boundary. The morphological and age similarities among the samples from
these three units indicate that the Hemipristis teeth occurring in each unit are conspecic, and herein
assigned to H. intermedia sp. nov. However, the Hemipristis teeth within the Chandler Bridge Formation,
roughly four million years younger than the aforementioned units, are more similar to Miocene H. serra.
Adnet et al. (2007) reported a sample of 10 Hemipristis teeth from the Rupelian of Balochistan that they
tentatively referred to H. serra. The two teeth they illustrated (gs 6, 15–17) are larger than and have
more extensive mesial denticulation compared to Eocene H. curvatus, and they are smaller than and less
denticulated than Miocene and younger H. serra. Those authors indicated that the teeth could represent
a transitional morphology between the two species. The two teeth illustrated by Adnet et al. (2007)
are both upper lateral teeth, and they fall within the range of variation we observed in the Catahoula
Formation Hemipristis sample. However, as we found the dentition of the Catahoula Formation sample
to be highly variable, we refrain from associating the Balochistan taxon with Hemipristis intermedia
sp. nov. until other tooth morphologies (i.e., upper anterior and lower lateral teeth) can be examined and
directly compared to those of the new species.
One additional taxon, H. tanakai Tomita, Yabumoto & Kuga, 2023, was recently erected based on a
total of ve teeth from widely disparate localities. The holotype is a complete tooth from the lower
Oligocene (Rupelian) Yamaga Formation in Japan, and the paratype, a broken tooth preserved in labial
view, may or may not be from the same lithostratigraphic unit and locality as the holotype. The authors
also included in this species the specimens reported by Adnet et al. (2007) as well as a tooth from South
Carolina. Unfortunately, this species may be considered a nomen dubium for several reasons. Firstly,
one of the three criteria used to dierentiate H. tanakai from other species is tooth height, which for
H. tanakai is apparently at least 1.5 cm. We note here that although the total height in the H. curvatus we
examined measured up to 1.2 cm, tooth height in H. serra can also measure 1.5 cm. Another characteristic
attributed to H. tanakai is that the mesial edge purportedly bears up to ve denticles. This morphology
is comparable to that of H. curvatus, where the mesial edge may completely lack denticulation or have
up to ve denticles. The Catahoula Formation Hemipristis teeth, as well as those from the Old Church
and Ashley formations (Müller 1999; Cicimurri et al. 2022) can have a far greater number of mesial
denticles (8+), indicating that the fossils from these units are not conspecic with H. tanakai.
As mentioned earlier, Tomita et al. (2023: g. 3) assigned a tooth from South Carolina to H. tanakai.
Unfortunately, the stratigraphic occurrence of the specimen is listed as “(Upper Oligocene) Chandler
Bridge Formation, Ashley Marl.” The Ashley Formation (Rupelian Stage) and Chandler Bridge
Formation (Chattian Stage) are two dierent lithostratigraphic units separated by approximately ve
million years of time. Although the authors provided color images of the specimen (Tomita et al. 2023:
g. 3a–e), shark teeth from the Ashley and Chandler Bridge formations can have similar coloration
(DJC, pers. obs.). Additionally, although the tooth shown has ve distinct mesial denticles, there are
European Journal of Taxonomy 984: 1–131 (2025)
26
several indistinct crenulations that could be counted as additional denticles (thereby increasing the
number to at least seven and exceeding the number attributed to H. tanakai).
Thirdly, according to Tomita et al. (2023) the apical-most denticle on the mesial cutting edge in
H. tanakai is located higher on the crown compared to the distal cutting edge. Although this may be true
for the holotype specimen of H. tanakai shown by Tomita et al. (2023: g. 2), it is not the case for the
South Carolina specimen illustrated in their g. 3a–e, and the mesial edge of their paratype specimen
(g. 3j) is not preserved. We suggest that the South Carolina specimen and broken paratype specimen
be excluded from the H. tanakai hypodigm, as the stratigraphic and temporal occurrence of the former
is ambiguous, and the latter specimen is poorly preserved (and only exposed from the matrix in labial
view). Additionally, the morphological features attributed to H. tanakai are ambiguous and based only
on the upper lateral morphology. In any event, the features of H. tanakai are inconsistent with those
of the Catahoula Formation taxon (i.e., greater than ten mesial denticles, apical-most denticle of the
distal edge is usually located higher than that on the mesial edge of the latter) and, if considered a valid
species, does not appear to be conspecic with H. intermedia sp. nov.
Family Carcharhinidae Jordan & Evermann, 1896
Genus Physogaleus Cappetta, 1980
Type species
Trigonodus secundus Winkler, 1874, Lutetian, Belgium.
Physogaleus contortus (Gibbes, 1849)
Fig. 7A–DD
Galeocerdo contortus Gibbes, 1849: 193.
Material examined
UNITED STATES OF AMERICA – Mississippi • 15 isolated teeth; Catahoula Formation; MMNS VP-
6623 (3 teeth), MMNS VP-6623.1 (Fig. 7D–F), MMNS VP-6623.2 (Fig. 7J–L), MMNS VP-6623.3
(Fig. 7M–O), MMNS VP-6623.4 (Fig. 7P–R), MMNS VP-6623.5 (Fig. 7S–U), MMNS VP-6623.6
(Fig. 7V–X), MMNS VP-6623.7 (Fig. 7Y–AA), MMNS VP-6623.8 (Fig. 7BB–DD), MMNS VP-12047
(Fig. 7A–C), SC2013.28.106 (Fig. 7G–I), SC2013.28.107, SC2013.28.108.
Description
Teeth are broad-based and moderately high-crowned, with the largest specimens measuring 15 mm
in mesio-distal width and 12 mm in apico-basal height. The crown of each specimen consists of a
conspicuous cusp and distal heel. The mesial cutting edge is elongated and sinuous, with the basal
portion being concave and the apical portion convex; the degree of curvature in these areas is variable
(i.e., weakly to strongly). The cutting edge is also serrated to varying degrees, and it may be nely and
evenly serrated along nearly its entire length or coarse along a portion but ne along another portion
of the same edge. Serrations are often coarse basally but ne apically. In mesial view, the cutting edge
is usually very sinuous, and the apical portion of the cusp has a twisted appearance that is particularly
conspicuous in mesial view (Fig. 7C, I, AA). The distal cutting edge is comparatively much shorter,
distally inclined, and nely serrated. The mesial and distal cutting edges intersect apically to form a
rather narrow, elongated, and distally inclined cusp. The serrations on the distal cutting edge are coarsest
basally but ne apically. Serrations on the mesial and distal cutting edges are simple. The transition
from distal cutting edge to distal heel is marked by a sharp curve or a notch (compare Fig. 7BB to 7G),
and on the former serrations occur within the curve and onto the apical edge of the rst denticle on the
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
27
heel (Fig. 7M). On the latter, the apical portion of the rst denticle on the heel is serrated (Fig. 7V). The
distal heel is low, elongated, oblique to a vertical plane, and denticulated. Typically, there are at least
four conspicuous denticles that decrease in size distally, where they blend into serrations near the crown
margin. Denticles on the distal heel are often weakly serrated on their apical edges. The root is bilobate
with thin, short but widely separated lobes. The prominent lingual root boss on each specimen is ablated
but was bisected by a nutritive groove (Fig. 7T, CC).
Remarks
Cicimurri et al. (2022) reported similar specimens from the Rupelian Ashley Formation of South
Carolina, and they discussed the stratigraphic and temporal ambiguity surrounding the morphology of
P. contortus as originally described by Gibbes (1849). In short, Gibbes noted that his South Carolina
specimens originated from “newer Eocene” deposits, which, based on fossil content, almost certainly
belong to the Ashley Formation due to the Rupelian age of the associated invertebrates he identied.
Gibbes (1849) specically noted the twisted appearance of the mesial cutting edge (Fig. 7C, F), and the
specimens he illustrated, particularly as seen in his gs 71–72, have coarse distal heel denticles. This
latter morphology conforms to the Oligocene specimens we collected from the Catahoula Formation,
as well as to the material reported by Cicimurri et al. (2022). We examined Miocene and Pliocene teeth
typically assigned to P. contortus that were collected from North and South Carolina and Florida, and
specimens of this age have a more evenly serrated heel compared to the Oligocene counterparts. We
must therefore take into consideration the possibility that Gibbes’ original concept of the contortus
morphology was for Oligocene Ashley Formation specimens. That the distal cutting edge serrations
of the Catahoula Formation specimens are already encroaching onto the distal heel foreshadows the
development of a uniformly serrated heel in the Mio-Pliocene descendants of the Oligocene taxon. The
specimens in our sample represent the rst occurrence of P. contortus from the northern Gulf Coastal
Plain of the USA
The Catahoula Formation P. contortus teeth exhibit monognathic heterodonty, with anterior teeth being
mesio-distally narrow and having a rather erect cusp (Fig. 7D–E), and lateral teeth being wider and
having a more distally inclined cusp (Fig. 7A–B). Additionally, cusp inclination increases but height
decreases towards the commissure (compare Fig. 7J and P). The teeth vary considerably in the width of
the cusp and the convexity of the mesial cutting edge, which we believe reects dignathic heterodonty.
Teeth that may be from upper les are those shown in Fig. 7A, G, and V, whereas those from lower les
are shown in Fig. 7M, S, and Y.
The Catahoula Formation P. contortus teeth can be separated from Galeocerdo (see below) by their
elongated and narrow cusp, simple serrations, lack of serrations at the cusp apex, and the “twisted”
nature of the mesial cutting edge. The teeth of Galeocerdo that we examined, including fossil and extant
specimens, have a straight mesial cutting edge (in mesial and occlusal views), and most of the Galeocerdo
species have compound serrations (Türtscher et al. 2021). The Oligocene P. contortus morphology
should therefore be separable from specimens identied as the “narrow crowned” morphology of
G. aduncus (Agassiz, 1835) (i.e., Türtscher et al. 2021) by this contorted apical portion of the cusp. The
Catahoula Formation P. contortus teeth dier from those we assigned to Physogaleus sp. (see below)
by being larger in overall size and by having a more elongated and usually sinuous cusp, conspicuous
mesial serrations extending more than two-thirds along the edge, more numerous and well-developed
distal denticles, and ne serrations that extend nearly to the apex of the distal cutting edge of the main
cusp. Pollerspöck and Unger (2023) recently suggested P. contortus be placed within Galeocerdonidae,
which was followed by Höltke et al. (2024). However, doing so necessitates placing all other species
of Physogaleus, which are quite dierent from Galeocerdo, within the family, or assigning the
contortus morphology to Galeocerdo. Based on the criteria we utilized to dierentiate P. contortus from
Galeocerdo, we maintain the former taxon within Carcharhinidae.
European Journal of Taxonomy 984: 1–131 (2025)
28
Fig. 7. Physogaleus contortus (Gibbes, 1849) (A–DD) and Physogaleus sp. (EE–JJ), teeth.
A–C. MMNS VP-12047, Physogaleus contortus, antero-lateral tooth. A. Labial view. B. Lingual view.
C. Mesial view. D–F. MMNS VP-6623.1, P. contortus, anterior tooth. D. Labial view. E. Lingual view.
F. Mesial view. G–I. SC2013.28.106, P. contortus, lateral tooth. G. Labial view. H. Lingual view.
I. Mesial view. J–L. MMNS VP-6623.2, P. contortus, anterior tooth. J. Labial view. K. Lingual view.
L. Mesial view. M–O. MMNS VP-6623.3, P. contortus, lateral tooth. M. Labial view. N. Lingual view.
O. Mesial view. P–R. MMNS VP-6623.4, P. contortus, lateral tooth. P. Labial view. Q. Lingual view.
R. Mesial view. S–U. MMNS VP-6623.5, P. contortus, anterior tooth. S. Labial view. T. Lingual view.
U. Mesial view. V–X. MMNS VP-6623.6, P. contortus, anterior tooth. V. Labial view. W. Lingual
view. X. Mesial view. Y–AA. MMNS VP-6623.7, P. contortus, lateral tooth. Y. Labial view. Z. Lingual
view. AA. Mesial view. BB–DD. MMNS VP-6623.8, P. contortus, antero-lateral tooth. BB. Labial view.
CC. Lingual view. DD. Mesial view. EE–GG. SC2013.28.134, Physogaleus sp., tooth. EE. Labial view.
FF. Lingual view. GG. Mesial view. HH–JJ. SC2013.28.136, Physogaleus sp., tooth. HH. Labial view.
II. Lingual view. JJ. Mesial view. Scale bars: A–DD = 1 cm; EE–JJ = 2 mm.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
29
Physogaleus sp.
Fig. 7EE–II
Material examined
UNITED STATES OF AMERICA – Mississippi • 14 isolated teeth; Catahoula Formation;
SC2013.28.134 (Fig. 7EE–GG), SC2013.28.135, SC2013.28.136 (Fig. 7HH–II), SC2013.28.137 to
28.143, SC2013.28.144 (4 teeth).
Description
The teeth are small, measuring up to 6 mm in mesio-distal width and less than 5 mm in apico-basal
height. The crown consists of a prominent cusp and a distal heel. The elongated mesial cutting edge
of the cusp is sharp and smooth (Fig. 7HH), but weak denticulation occurs at the base of the edge on
SC2013.28.134 (Fig. 7EE). The mesial edge ranges from straight, to sinuous, to weakly convex or
weakly concave (Fig. 7FF, II). The distal cutting edge is also smooth but much shorter and may be
vertical to distally inclined. The mesial and distal edges intersect apically to form a sharp apex. The
distal heel is low and bears two or three denticles. These denticles decrease in size distally, and the
distal-most denticle is very inconspicuous. The labial crown face is smooth and at, whereas the lingual
crown face is smooth and convex (Fig. 7JJ). The root is bilobate, with elongated, highly divergent sub-
rectangular lobes that are separated by a broad V-shaped interlobe area. The teeth have a thin, medially
located lingual nutritive groove (Fig. 7FF, II).
Remarks
Our small sample appears to reect monognathic and dignathic heterodonty within the dentition of this
taxon. Anterior teeth are mesio-distally narrower than lateral teeth, and the cusp of anterior teeth is more
erect. Additionally, the main cusp becomes more inclined towards the jaw commissure. The distal heel
of lateral teeth is more horizontal than that of anterior teeth, and it is more elongated, with a greater
number of denticles. Teeth that we believe are from the lower dentition have a narrower main cusp with
a more concave mesial cutting edge (Fig. 7HH) compared to upper teeth (Fig. 7EE).
These teeth dier from those of Physogaleus contortus and Galeocerdo from the Catahoula Formation
by lacking serrated mesial and distal cutting edges. Additionally, they can be separated from the teeth of
Rhizoprionodon and Sphyrnidae (see below) by having denticles at the base of the mesial cutting edge
and on the distal heel. Ebersole et al. (2021) reported a single Physogaleus sp. tooth from the Glendon
Limestone Member of the Byram Formation (NP23) in southwestern Alabama that is comparable to the
Catahoula Formation material. Cicimurri et al. (2022) later reported two specimens from the Rupelian
Ashley Formation of South Carolina that they considered to be conspecic with the Physogaleus sp.
specimens previously documented by Cicimurri & Knight (2009) from the Chattian Chandler Bridge
Formation in South Carolina. The Catahoula Formation sample is younger than the Alabama occurrence
and bracketed in age by the two South Carolina Oligocene occurrences, but it is possible that all the
material is conspecic. Although the Catahoula Formation sample is rather small and imperfectly
preserved, the teeth appear to dier from those of Eocene P. secundus (Winkler, 1874) by the weakly
crenulated lower portion of their mesial cutting edge and the poorly developed distal heel denticles.
They also dier from the Eocene P. alabamensis (Leriche, 1942) and Oligocene P. latus (Storms, 1894)
by their smaller size and poorly developed mesial cutting edge and distal heel denticles (Reinecke et al.
2014; Ebersole et al. 2019). Larger samples from both the Gulf and Atlantic coastal plains are necessary
to make more precise comparisons and identications of the Oligocene Physogaleus sp. teeth.
European Journal of Taxonomy 984: 1–131 (2025)
30
Genus Rhizoprionodon Whitley, 1929
Type species
Carcharias crenidens Klunzinger, 1880, Extant.
Rhizoprionodon sp.
Fig. 8A–D
Material examined
UNITED STATES OF AMERICA – Mississippi • 36 isolated teeth; Catahoula Formation; MMNS
VP-8396 (6 teeth), MMNS VP-8737, SC2013.28.145 (Fig. 8A–B), SC2013.28.146, SC2013.28.147,
SC2013.28.148 (Fig. 8C–D), SC2013.28.149, SC2013.28.150, SC2013.28.151 (7 teeth), SC2013.28.152
(9 teeth), SC2013.28.153 (7 teeth).
Description
Teeth are small and generally measure approximately 5 mm in width (mesio-distal). The crown consists
predominantly of a main cusp and a much smaller distal heel. The cusp varies in height, degree of distal
inclination, and width (compare Fig. 8A to C). The labial crown face is rather at, but the lingual face
is convex, and enameloid is smooth. The mesial cutting edge is elongated, smooth, and may be straight,
weakly convex, or concave to varying degrees. The distal cutting edge is smooth and approximately
one-half as long as the mesial edge, and it may be straight or convex (compare Fig. 8B to D). The distal
heel is low and varies in length, and it may be uniformly convex or somewhat cuspidate. The distal heel
is separated from the distal cutting edge by a distinct notch (Fig. 8A). The root is bilobate with short but
widely diverging lobes being separated by a prominent lingual nutritive groove (Fig. 8B).
Remarks
These teeth are of small size and most of them are imperfectly preserved, which inhibits our ability to
accurately identify them taxonomically. However, we believe that the sample demonstrates monognathic,
dignathic, and gynandric heterodonty within the taxon based on the morphological criteria recently
presented by Ebersole et al. (2023). With respect to monognathic heterodonty, the teeth increase in width
but decrease in height from the symphysis to the commissure. Dignathic heterodonty is apparent in cusp
width, with that of upper teeth being more than twice as large as that of lower teeth (compare Fig. 8B
to D). Anterior teeth of mature, breeding season males have a much more concave mesial cutting edge
compared to non-breeding male teeth and female teeth (gynandry). The Catahoula Formation specimens
can be dierentiated from sphyrnid teeth in our sample (see below) based on their smaller size, shorter
main cusp, and shorter and more convex distal heel. However, several authors have commented on the
diculty in dierentiating isolated teeth of extant Rhizoprionodon from those of taxa within Sphyrnidae
(i.e., Purdy et al. 2001; Ward & Bonavia 2001), as there is morphological dental overlap between some
of the species within these genera (Ebersole et al. 2023).
The Catahoula teeth in our sample are morphologically similar to those of two named fossil species,
including the Eocene Rhizoprionodon ganntourensis (Arambourg, 1952) and the Miocene R. cheuri
(Joleaud, 1912). The former species has been documented in lower-to-middle Eocene deposits in the
Gulf Coastal Plain of Alabama and Mississippi (Ebersole et al. 2019, 2023). The Catahoula Formation
sample is not large enough to determine morphological similarity to R. ganntourensis and, in any case, the
R. ganntourensis morphology has not been documented from any fossil deposits that are stratigraphically
younger than the middle Eocene. Additionally, there are a number of taxonomic issues surrounding
R. cheuri from the type locality that warrant further evaluation of this species (see Ebersole et al. 2023
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
31
for a discussion of this taxon). We refrain from assigning the Catahoula Formation teeth to any particular
species of Rhizoprionodon due to our small sample size.
Genus Carcharhinus de Blainville, 1816
Type species
Carcharhinus melanopterus Quoy & Gaimard, 1824, Extant.
Carcharhinus acuarius (Probst, 1879)
Fig. 8E–H, Q–S
Alopecias acuarius Probst, 1879: 140.
Material examined
UNITED STATES OF AMERICA – Mississippi • 986 isolated teeth; Catahoula Formation;
SC2013.28.188 to 28.193, SC2013.28.194 (Fig. 8G–H), SC2013.28.195 (Fig. 8E–F), SC2013.28.196
Fig. 8. Rhizoprionodon sp. (A–D), Carcharhinus acuarius (Probst, 1879) (E–H, Q–S), and C. elongatus
(Leriche, 1910) (I–P, T–V), teeth. A–B. SC2013.28.145, Rhizoprionodon sp., upper right anterior tooth.
A. Labial view. B. Lingual view. C–D. SC2013.28.148, Rhizoprionodon sp., lower right lateral tooth.
C. Labial view. D. Lingual view. E–F. SC2013.28.195, Carcharhinus acuarius, upper right lateral
tooth. E. Labial view. F. Lingual view. G–H. SC2013.28.194, C. acuarius, upper right anterior tooth.
G. Labial view. H. Lingual view. I–J. SC2013.28.211, C. elongatus, upper left anterolateral tooth.
I. Labial view. J. Lingual view. K–L. SC2013.28.215, C. elongatus, upper left lateral tooth. K. Labial
view. L. Lingual view. M–N. SC2013.28.235, C. elongatus, upper right posterolateral tooth. M. Labial
view. N. Lingual view. O–P. SC2013.28.251, C. elongatus, upper right lateral tooth. O. Labial view.
P. Lingual view. Q–S. SC2013.28.201, C. acuarius, lower tooth. Q. Labial view. R. Lingual view.
S. Mesial view. T–V. SC2013.28.244, C. elongatus, lower tooth. T. Labial view. U. Lingual view.
V. Mesial view. Scale bars: A–B = 3 mm; C–D = 2 mm; E–V = 5 mm.
European Journal of Taxonomy 984: 1–131 (2025)
32
to 28.200, SC2013.28.201 (Fig. 8Q–S), SC2013.28.202 to 28.204, SC2013.28.205 (149 teeth),
SC2013.28.206 (206 teeth), SC2013.28.207 (169 teeth), SC2013.28.208 (305 teeth), SC2013.28.209
(121 teeth), SC2013.28.266 (3 teeth), SC2013.28.267 (16 teeth).
Description
The largest teeth in our sample measure 10 mm in apico-basial height and 8 mm in mesio-distal width.
The crown consists of a cusp and low lateral shoulders. The cusp varies considerably in height and width,
ranging from tall and narrow (mesio-distally) to rather low and broad. In prole the tall and narrow teeth
have a slight lingual curvature, but broader teeth are erect. The labial face is at to weakly convex,
whereas the lingual face is convex. The crown enameloid is smooth. The mesial and distal cutting
edges are smooth and extend from the cusp apex and onto the lateral shoulders. The shoulders are rather
low, vary in length (even between the mesial and distal sides of a given tooth), and may be straight to
somewhat convex. The root is bilobate with the lobes being elongated, narrow and somewhat closely
spaced, or somewhat rectangular and widely diverging. The U-shaped interlobe area is correspondingly
deep or shallow. The thickened lingual root face is bisected by a long and deep nutritive groove.
Remarks
We observed variation in tooth shape and size in the Catahoula Formation sample that we believe
reects heterodonty within a single species. A parasymphyseal tooth (i.e., located adjacent to the jaw
symphysis) is small in overall size, has a tall and narrow crown and robust root with short lobes, and
the root is equal in height to the crown (see an equivalent tooth in Cappetta 1970: pl. 17). Anterior teeth
have a tall and narrow cusp with elongated root lobes, and the lateral shoulders are rather short and
oblique. Lateral teeth have a somewhat broader and lower cusp, the lateral shoulders are more elongated
and perpendicular to cusp height, and the shorter root lobes are more rectangular and widely diverging.
Upper anterior teeth (Fig. 8G–H) have shorter root lobes compared to lower anteriors. Upper lateral
teeth have broader and more distally inclined cusps than lower laterals (compare Fig. 8E–F to Q–S). We
also observed ontogenetic heterodonty in our sample, as small teeth of presumed juvenile individuals
appear to be gracile versions of their larger (adult) counterparts.
These teeth dier from those of supercially similar Carcharias cuspidatus teeth in our sample by their
much smaller overall size, much shorter root lobes, and lack of lateral cusplets. Additionally, teeth of
a. Pseudocarcharias sp. are larger and have a more robust crown, root lobes are more elongated and
pointed at their extremities, and a short nutritive groove is limited to the rather thin lingual boss. Alopias
sp. teeth are comparatively larger and have broader, more robust crowns.
Probst (1879) originally assigned his new Early Miocene acuarius species to Alopecias, and Cappetta
(1970), who identied the species as Aprionodon, illustrated additional specimens (his pl. 17) that
provided a more comprehensive overview of heterodonty within the species. Although the species was
subsequently synonymized with Isogomphodon (i.e., Bolliger et al. 1995), da Silva Rodrigues-Filho
et al. (2023) recently determined that extant Isogomphodon is genetically inseparable from, and should
be synonymized with, Carcharhinus, which we follow herein. With their inclusion in Carcharhinus, the
various fossil species formerly assigned to Isogomphodon are herein referred to as the daggernose shark
species-group within Carcharhinus.
The Catahoula Formation teeth conform in both size range and morphology to C. acuarius. This taxon
was apparently widely distributed during the Miocene (see Carrillo-Briceño et al. 2016, 2019; Fialho
et al. 2019; Perez 2022; Villafaña et al. 2020). Cicimurri & Ebersole (2021) and Ebersole & Cicimurri
(in press) identied Isogomphodon sp. in the lower Oligocene (Rupelian) Roseeld Formation of
Louisiana, and comparison of the material they illustrated to the much larger Catahoula Formation
sample indicates that the records are conspecic.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
33
The unique body shape of the extant daggernose shark, C. oxyrhynchus (Valenciennes in Müller & Henle,
1839), has been proposed as an adaptation to life within the Amazon River estuary, where conditions
are highly turbid (Compagno 1984). The late Eocene (Priabonian) daggernose shark, Carcharhinus
aikenensis (Cicimurri & Knight, 2019), and the Catahoula Formation species also apparently preferred
a similar environment (see Discussion below).
Carcharhinus elongatus (Leriche, 1910)
Fig. 8I–P, T–V
Sphyrna elongata Leriche, 1910: 300–301.
Material examined
UNITED STATES OF AMERICA – Mississippi • 291 isolated teeth; Catahoula Formation;
MMNS VP-6627 (92 teeth), SC2013.28.210, SC2013.28.211 (Fig. 8I–J), SC2013.28.212 to 28.214,
SC2013.28.215 (Fig. 8K–L), SC2013.28.216 to 28.218, SC2013.28.219 (6 teeth), SC2013.28.220
(2 teeth), SC2013.28.221 (9 teeth), SC2013.28.222 (7 teeth), SC2013.28.223 to 28.234, SC2013.28.235
(Fig. 8M–N), SC2013.28.236 to 28.238, SC2013.28.239 (4 teeth), SC2013.28.240 (4 teeth),
SC2013.28.241 (6 teeth), SC2013.28.242 (8 teeth), SC2013.28.243, SC2013.28.244 (Fig. 8T–V),
SC2013.28.245 to 28.247, SC2013.28.248 (16 teeth), SC2013.28.249 (7 teeth), SC2013.28.250,
SC2013.28.251 (Fig. 8O–P), SC2013.28.252, SC2013.28.253, SC2013.28.254 (4 teeth), SC2013.28.255
(7 teeth), SC2013.28.256 to 28.259, SC2013.28.260 (4 teeth), SC2013.28.261 (7 teeth), SC2013.28.262
(61 teeth), SC2013.28.263 (9 teeth).
Description
Two tooth morphologies are present, the most common of which has a broadly triangular main cusp
that is anked by mesial and distal heels (Fig. 8I–P). These teeth are typically mesio-distally wider than
tall (apico-basally), measuring up to 15 mm and 12 mm, respectively, in these dimensions. However,
some specimens are taller than wide. The cusp is broadly triangular, although width diers among the
teeth, and it may be vertical but is more often distally inclined. The labial face is virtually at, whereas
the lingual face is convex, and enameloid on both sides is smooth. The mesial and distal cutting edges
are smooth and complete along the cusp. The mesial and distal shoulders vary in length, even between
the mesial and distal sides of a tooth, and they may be horizontal or oblique. The cutting edges of the
shoulders can be serrated, although serration density and size vary, even along a single cutting edge.
The shoulders are separated from the main cusp by a tiny notch. The root is low, particularly in labial
view, and strongly bilobate. The root lobes are elongated, highly divergent, and separated by a shallow
but broad U-shaped or V-shaped interlobe area. The lobes can be described as sub-rectangular with their
distal ends ranging from rounded to pointed. The thickened lingual root face is bisected by a wide but
shallow nutritive groove that forms a basal notch on some specimens.
The second morphology includes roughly T-shaped teeth. The crowns of these teeth bear a cusp that
is somewhat tall and rather narrow, but cusp height varies, and it may be vertical or distally inclined
to varying degrees. The cutting edges of these teeth are straight and smooth and extend onto lateral
shoulders (Fig. 8T). These shoulders may be oblique or perpendicular to cusp height. The root has rather
short lobes that are very widely diverging (Fig. 8U), with the basal margin being at to only weakly
concave. The lingual nutritive groove is thin and long.
Remarks
Monognathic, dignathic, and ontogenetic heterodonty are represented in our sample of teeth. Upper
anterior teeth are taller than wide and symmetrical (or nearly so), whereas lateral teeth are wider than
European Journal of Taxonomy 984: 1–131 (2025)
34
tall and have a distally inclined cusp. Inclination of the main cusp increases towards the jaw commissure
and tooth height correspondingly decreases (compare Fig. 8I–J, K–L and M–N). Upper teeth have a
much broader cusp and larger root compared to those in lower les (compare Fig. 8K to U). Lower teeth
lack or bear only very weak serrations on the lateral shoulders, and the basal root margin is straighter
(compare Fig 8T to O). Ontogenetic heterodonty is expressed as a dierence in stoutness among the
dierent tooth size classes, with small teeth being relatively gracile (presumed juveniles) compared
to the large, robust specimens (presumed adults). Serration size and density on the lateral shoulders is
also variable and may be virtually absent (Fig. 8O), weakly developed (Fig. 8M), or strongly developed
(Fig. 8I). However, this does not appear to reect monognathic heterodonty or ontogeny. Rather, it is
variation among individual teeth in each le, as a particular serration size or density (or lack thereof) is
not indicative of any specic jaw position, and small teeth (juveniles) exhibit the same variation as large
(adult) teeth.
The teeth described above fall within the size range of Carcharhinus elongatus (Leriche, 1910) and
C. gibbesii (Woodward, 1889) (see Reinecke et al. 2014), species that have been reported from the
Oligocene of North America and Europe (Reinecke et al. 2001, 2005; Cicimurri & Knight 2009; Cicimurri
et al. 2022). However, the teeth of C. gibbesii appear to have coarse and uniformly serrated lateral heels,
whereas the heels of C. elongatus are irregularly serrated (similar to the condition in Physogaleus) or
even smooth. We identify the Catahoula Formation teeth as C. elongatus because the serrations are
much weaker (or altogether absent) compared to C. gibbesii. Reinecke et al. (2014) indicated that some
Oligocene teeth represent a transitional species between C. elongatus and C. gibbesii, although this
intermediate species has yet to be determined. Müller (1999) reported C. elongatus from the Oligocene
Old Church Formation of Virginia, but we concur with Cicimurri et al. (2022) that the coarse serration
pattern of the teeth he illustrated (pl. 6 gs 5–9) is more like that of C. gibbesii. Müller (1999) also
reported C. elongatus and C. gibbesii from the Ashley Formation of South Carolina, but he did not
illustrate any specimens, and we could not verify their identity.
Family Triakidae Gray, 1851
Genus Galeorhinus de Blainville, 1816
Type species
Squalus galeus Linnaeus, 1758, Extant.
Galeorhinus sp.
Fig. 9A–B
Material examined
UNITED STATES OF AMERICA – Mississippi • 1 isolated tooth; Catahoula Formation; SC2013.28.114
(Fig. 9A–B).
Description
SC2013.28.114 is an incomplete tooth having a crown width measuring 2.5 mm and crown height of
approximately 1.2 mm. The mesial edge of each tooth is smooth, elongated, and convex basally but
otherwise straight. This edge is strongly inclined distally, and a smooth cutting edge is only obvious
along its lower one-half. The distal cutting edge is short and lingually inclined, and it intersects apically
with the mesial margin to form a small distally inclined cusp. A short, oblique distal heel bears a
series of three denticles that decrease in size basally (Fig. 9B). The labial face is weakly convex and
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
35
appears to have been thickened at the base (Fig. 9A). The lingual face is more strongly convex. Crown
ornamentation is not obvious, but the specimen is ablated. The root is not preserved.
Remarks
We tentatively identify specimen SC2013.28.114 (Fig. 9A–B) as Galeorhinus due to its small size and
apparently thickened labial crown foot (Fig. 9A). The tooth diers from supercially similar teeth of
Sphyrnidae (see below) and other Carcharhinidae from the Jones Branch locality by having a high
and oblique distal heel that bears numerous well-dened denticles. It also diers from Carcharhinus
elongatus and Physogaleus spp. by being unserrated and lacking denticles on the mesial cutting edge.
Additionally, the labial crown foot of Carcharhinus spp. and Physogaleus spp. is at and not thickened
to overhang the root. The unserrated cutting edges easily separate the two teeth from those of Galeocerdo
(see below).
Ebersole et al. (2019) identied three Eocene Galeorhinus species from Gulf Coastal Plain deposits
in Alabama, namely Galeorhinus a. G. duchaussoisi Adnet & Cappetta, 2008, G. louisi Adnet &
Cappetta, 2008, and G. ypresiensis (Casier, 1946). However, none of these species are known to persist
into the Oligocene (Adnet & Cappetta 2008). The Catahoula Formation specimens are similar to a lateral
tooth identied by Cicimurri & Knight (2009) from the Chattian Chandler Bridge Formation of South
Carolina, and Müller (1999) noted a specimen from the Rupelian Old Church Formation of Virginia
that is comparable to SC2013.28.114. Reinecke et al. (2005) and Haye et al. (2008) documented several
Oligocene Galeorhinus sp. from the late Oligocene (late Chattian) of Germany, and the Catahoula
Fig. 9. Galeorhinus sp. (A–B), Euselachii fam., gen. et sp. indet. (C–D), Pachyscyllium distans (Probst,
1879) (E–J), and Pachyscyllium sp. (K–P), teeth. A–B. SC2013.28.114, Galeorhinus sp., lateral tooth.
A. Labial view. B. Lingual view. C–D. SC2013.28.115, Euselachii fam., gen. et sp. indet., posterior tooth.
C. Labial view. D. Lingual view. E–F. SC2013.28.117, Pachyscyllium distans, anterior tooth. E. Labial
view. F. Lingual view. G–H. SC2013.28.116, P. distans, lateral tooth. G. Labial view. H. Lingual view.
I–J. SC2013.28.125, P. distans, tooth. I. Labial view. J. Lingual view. K–L. SC2013.28.126, Pachyscyllium
sp., anterolateral tooth. K. Labial view. L. Lingual view. M–N. SC2013.28.127, Pachyscyllium sp.,
anterior tooth. M. Labial view. N. Lingual view. O–P. MMNS VP-8796, Pachyscyllium sp., lateral
tooth. O. Labial view. P. Lingual view. Scale bars = 1 mm.
European Journal of Taxonomy 984: 1–131 (2025)
36
Formation material diers from some of those specimens by the lack of labial ornamentation (Reinecke
et al. 2005). Unfortunately, the poor preservation of the singular Catahoula Formation specimen available
to us inhibits our ability to eectively identify the taxon to species.
Family Scyliorhinidae Gill, 1862
Genus Pachyscyllium Reinecke et al., 2005
Type species
Pachyscyllium albigensis Reinecke et al., 2005, Rupelian, Mainz Basin, western Germany.
Pachyscyllium distans (Probst, 1879)
Fig. 9E–J
Scyllium distans Probst, 1879: 170–171.
Material examined
UNITED STATES OF AMERICA – Mississippi • 11 isolated teeth; Catahoula Formation; MMNS
VP-12048, SC2013.28.116 (Fig. 9G–H), SC2013.28.117 (Fig. 9E–F), SC2013.28.118 to 28.124,
SC2013.28.125 (Fig. 9I–J).
Description
Very small teeth measuring up to 2 mm in total height and 1.5 mm in crown width. The crown consists
of a main cusp that is typically anked by a single pair of lateral cusplets. The main cusp ranges from
narrow, tall, and vertical to broad, low, and distally inclined (depending on jaw position). The labial
face of the main cusp is convex, and the crown foot is thickened such that it weakly overhangs the root.
Additionally, the crown foot may be straight or weakly concave. The lingual face of the main cusp and
lateral cusplets is also convex. The labial face bears vertical ridges that may extend to one-half the crown
height (Fig. 9I); these ridges may occur across the entire labial face or may be restricted to the region
below the lateral cusplets. The lingual face is generally smooth, but faint ridges may occur on the lateral
cusplets. The lateral cusplets may be needle-like and extend up to one-third of the total crown height, or
they may be low and broadly triangular. Smooth mesial and distal cutting edges extend along the main
cusp and lateral cusplets. The bilobate root appears higher lingually than is apparent in labial view. Root
lobes are very short and divergent, separated by a shallow and narrow interlobe area. The root is divided
into very short, sub-triangular to teardrop-shaped lobes by an elongated nutritive groove (Fig. 9F, H).
Remarks
The available sample indicates that monognathic heterodonty was developed in this taxon. Anterior
teeth have a rather narrow, tall, sharply pointed main cusp, and lateral cusplets are also tall and needle-
like. Teeth believed to be from lateral les have a comparatively lower and broader main cusp that is
distally inclined, and lateral cusplets are also shorter and broader (Fig. 9G–H). The main cusp appears to
become more inclined the closer a tooth was located to the commissure. Most of the teeth in our sample
exhibit one pair of lateral cusplets, but one specimen exhibits two cusplets on the mesial side (Fig. 9I–J).
These diminutive teeth will not be confused with most other similarly shaped shark teeth found in the
Catahoula Formation. The lone exception is another Pachyscyllium morphotype (see below), which
diers from P. distans in several ways, the most conspicuous being the absence of crown ornamentation.
Case (1980) documented P. distans from the Oligocene River Bend Formation of North Carolina. The
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
37
species was apparently geographically widespread and temporally long-ranging, occurring in strata of
Oligocene to Pliocene age in Europe (Reinecke et al. 2001, 2005, 2011, 2014; Collareta et al. 2020;
Villafaña et al. 2020; Szabó et al. 2022).
Pachyscyllium sp.
Fig. 9K–P
Material examined
UNITED STATES OF AMERICA – Mississippi • 19 isolated teeth; Catahoula Formation; MMNS VP-
8746 (6 teeth), MMNS VP-8796 (Fig. 9O–P), SC2013.28.126 (Fig. 9K–L), SC2013.28.127 (Fig. 9M–
N), SC2013.28.128 to 28.131, SC2013.28.132 (2 teeth), SC2013.28.133 (4 teeth).
Description
All but one of the specimens are broken, but these are morphologically comparable to the complete
tooth, SC2013.28.126 (Fig. 9K–L). This specimen measures 2.5 mm in crown width and just under
3 mm in total height. The crown consists of a main cusp that is slightly distally inclined, and a single
pair of large lateral cusplets. The main cusp is tall, triangular, rather narrow, sharply pointed, and its
labial and lingual faces are convex. The lateral cusplets are broad, short, pointed, located very low on
the crown, and well separated from the main cusp (Fig. 9K). Smooth cutting edges extend along the
main cusp and lateral cusplets. In apical view, the lateral cusplets appear to be located anterior to the
labial face of the main cusp. The labial crown foot is thickened, concave, and conspicuously overhangs
the root. The crown enameloid lacks ornamentation. The root is low (in labial view) and bilobate with
lobes extending laterally just beyond the crown margin. The root lobes are very widely diverging and
separated by a broad and shallow U-shaped interlobe area. The lingual attachment surface is at and
rather thin on the lobes, but a large medial boss is bisected by a thin, deep nutritive groove (Fig. 9L).
Remarks
As noted above, the additional incomplete teeth in the sample are morphologically similar to the
complete tooth represented by SC2013.28.126. However, we did note some slight dierences amongst
the teeth, namely the width, robustness, and inclination of the main cusp, as well as the height of the
lateral cusplets. Several specimens have a vertical main cusp and symmetrical crowns (Fig. 9M–N),
whereas those like SC2013.28.126 have a slightly distally inclined cusp (Fig. 9K, O). We believe
that these dierences represent monognathic heterodonty within the same taxon, where anterior teeth
are symmetrical and lateral teeth have distally inclined main cusps. Variations in tooth robustness
(i.e., some specimens are more gracile than others) could reect dignathic, ontogenetic, or even
gynandric heterodonty, the latter of which has been documented in other scyliorhinid sharks (Soares &
de Carvalho 2019). Cicimurri et al. (2022) reported an incomplete Pachyscyllium sp. specimen from
the Rupelian (NP24) Ashley Formation of South Carolina, but that tooth exhibits short longitudinal
ridges that are not present on these Catahoula Formation specimens. Ebersole et al. (2021) reported a
single Pachyscyllium sp. tooth from the Rupelian (NP23) Glendon Limestone Member of the Byram
Formation of Alabama, and Ebersole & Cicimurri (in press) also reported a similar Pachyscyllium sp.
tooth from the Rupelian Roseeld Formation in Louisiana. Although these teeth are comparable to those
described above, additional material from these lithostratigraphic units are needed to ascertain whether
the morphologies are conspecic.
The gross morphology of the Catahoula Formation teeth is comparable to that of various Oligo-Miocene
Pachyscyllium species that have been described, but there are some apparent dierences. The Catahoula
Formation Pachyscyllium sp. teeth have smooth enameloid, whereas those of P. distans possess distinct
European Journal of Taxonomy 984: 1–131 (2025)
38
vertical ridges on the lower portion of the labial face and often on the lingual face of the lateral cusplets.
The Catahoula Formation specimens appear to dier from those of P. dachiardii (Lawley, 1876) by
having consistently shorter lateral cusplets, and from P. albigensis Reinecke et al., 2005 by their larger
overall size (Reinecke et al. 2005; Reinecke & Radwański 2015). Although there is some morphological
overlap with P. braaschi Reinecke et al., 2005, the few Catahoula Formation specimens available to us
appear to have shorter and less divergent lateral cusplets (Reinecke et al. 2005, 2014; Haye et al. 2008).
Family Sphyrnidae Bonaparte, 1840
Genus Sphyrna Ranesque, 1810
Type species
Squalus zygaena Linnaeus, 1758, Extant.
“Sphyrna” gracile sp. nov.
urn:lsid:zoobank.org:act:4B859E67-6145-4422-98B6-251EB701F01E
Fig. 10
Diagnosis
Mesio-distally wide teeth consisting of a large main cusp and a distal heel. The main cusp is broadly
triangular and distally inclined to varying degrees. The mesial cutting edge is straight to weakly convex
on the main cusp, but it extends to the end of the mesial root lobe generally through a sloping transition
at the base of the cusp. The distal cutting edge is shorter and straight to weakly convex. The distal heel
is elongated, low, straight to weakly convex, and dierentiated from the distal cutting edge by a shallow
notch. All cutting edges are smooth. The root is bilobate with short, sub-rectangular lobes that are highly
diverging. The basal margin is straight to weakly concave. The lingual root face is thick, and there is
a distinctive medially located nutritive groove. These teeth dier from fossil species reported in the
literature, like those of the Miocene Sphyrna arambourgi Cappetta, 1970, by having a wider main cusp
and weakly sinuous (as opposed to straight) mesial cutting edge. Additionally, “S.” gracile sp. nov. teeth
can be separated from those of both S. arambourgi and S. integra (Probst, 1878) by having an elongated
and straight to weakly convex distal heel (as opposed to being rather short and occasionally cuspidate
in the latter taxa). Furthermore, the lower teeth of the former taxon have an angular mesial cutting edge,
whereas this edge is curved in the latter taxa. “Sphyrna” gracile teeth dier from those of the Miocene
S. laevissima (Cope, 1867) by being less robust and by being smaller in mesio-distal width (up to 6 mm
for “S.” gracile vs 1 cm for S. laevissima).
Etymology
The species name alludes to the small size and delicate appearance of the teeth.
Material examined
Holotype
UNITED STATES OF AMERICA – Mississippi • upper right lateral tooth; Catahoula Formation;
SC2013.28.158 (Fig. 10O–Q).
Paratypes
UNITED STATES OF AMERICA – Mississippi • lower left anterior tooth; Catahoula Formation;
SC2013.28.155 (Fig. 10A–C) • lower left lateral tooth; Catahoula Formation; SC2013.28.162
(Fig. 10L–N).
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
39
Other material
UNITED STATES OF AMERICA – Mississippi • 28 isolated teeth; Catahoula Formation; SC2013.28.154,
SC2013.28.156 (Fig. 10J–K), SC2013.28.157 (Fig. 10R–S), SC2013.28.158 to 28.160, SC2013.28.161
(Fig.10T–U), SC2013.28.162, SC2013.28.163 (7 teeth), SC2013.28.164 (10 teeth), SC2013.28.912
(Fig. 10F–G), SC2013.28.913 (Fig. 10D–E), SC2013.28.914 (Fig. 10H–I).
Stratum typicum
Shelly, argillaceous sand of the Jones Branch fossil horizon, lower Catahoula Formation, Chattian Stage
(horizon no longer accessible).
Locus typicus
Site MS.77.011, Jones Branch, tributary owing into the Chickasawhay River, south of Waynesboro,
Wayne County, Mississippi, USA.
Description
These small teeth measure up to 6 mm in mesio-distal width and slightly over 5 mm in overall height
(apico-basal). The crown consists of a conspicuous cusp and a distal heel. The mesial cutting edge
is sharp, smooth, and weakly to strongly concave. The mesial cutting edge exhibits a basal heel that
may be short or elongated, poorly or conspicuously dierentiated from the cusp, and oblique to nearly
perpendicular to the cusp. The distal cutting edge is smooth and sharp, straight to convex, may be nearly
vertical to moderately distally inclined, and is shorter than the mesial edge. The mesial and distal cutting
edges intersect apically to form the cusp, which itself is rather narrow but sharply pointed. An elongated
distal heel is very low, weakly convex to angular, and the edge is smooth. A conspicuous notch is located
at the junction of the heel and the distal cutting edge, and the apex of the heel is located just distal to the
notch. The bilobate root has elongated, widely diverging, sub-rectangular lobes with rounded ends. The
Fig. 10. “Sphyrna” gracile sp. nov., teeth. A–C. SC2013.28.155 (paratype), lower left anterior tooth.
A. Labial view. B. Lingual view. C. Mesial view. D–E. SC2013.28.913, lower right lateral tooth.
D. Labial view. E. Lingual view. F–G. SC2013.28.912, lower left lateral tooth. F. Labial view. G. Lingual
view. H–I. SC2013.28.914, lower left lateral tooth. H. Labial view. I. Lingual view. J–K. SC2013.28.156,
upper left lateral tooth. J. Labial view. K. Lingual view. L–N. SC2013.28.162 (paratype), lower left
lateral tooth. L. Labial view. M. Lingual view. N. Mesial view. O–Q. SC2013.28.158 (holotype), upper
right lateral tooth. O. Labial view. P. Lingual view. Q. Mesial view. R–S. SC2013.28.157, upper left
anterior tooth. R. Labial view. S. Lingual view. T–U. SC2013.28.161, upper right lateral tooth. T. Labial
view. U. Lingual view. Scale bars = 3 mm.
European Journal of Taxonomy 984: 1–131 (2025)
40
interlobe area is low and broadly U-shaped or may be absent (straight basal margin). The lingual root
face is bisected by a short but deep nutritive groove.
Remarks
Although the teeth described above share morphological features that occur on teeth of extant Sphyrnidae,
there are dierences among the various taxa (see below). Assigning the fossils to the extant genus
Sphyrna is problematic based on molecular divergence work by Lim et al. (2010), which indicates
that the genera Eusphyra and Sphyrna did not diverge from their most recent common ancestor until
the Early-to-Middle Miocene, four to seven million years after deposition of the Catahoula Formation
fossil bed. For the purposes of this report, we follow Ebersole et al. (2024a) in placing the generic name
Sphyrna within quotations, acknowledging dental similarities between the Oligocene and extant species,
and taking into account divergence estimates that may result in future placement of the fossil species in
a new genus.
To aid our evaluation of the Catahoula Formation sphyrnid sample, we examined the jaws of several
extant Sphyrna species, including S. lewini (Grith & Smith, 1834) (SC2001.7.1), S. mokarran
(Rüppell, 1837) (SC2000.120.2), S. tiburo (Linnaeus, 1758) (SC96.77.3), and S. zygaena (Linnaeus,
1758) (MSC 42600). Additionally, we utilized the illustrated dentitions of S. media Springer, 1940
and S. tudes (Valenciennes, 1822) provided by Gilbert (1967: gs 14 and 19, respectively). “Sphyrna”
gracile sp. nov. teeth are much smaller in overall size and less stout compared to the teeth of presumed
extant relatives Sphyrna mokarran and S. zygaena, which are also serrated to varying degrees. The
upper teeth of “Sphyrna” gracile dier from those of S. lewini by having a less elongated mesial crown
foot and a less convex medial portion of the mesial cutting edge. Additionally, the mesial cutting edge
on the lower teeth of the former taxon has an angular appearance, whereas this edge on the lower teeth
of the latter taxon appears strongly curved. The upper teeth of extant S. media have more convex distal
cutting edges, a more medially convex portion of the mesial edge, and a shorter distal heel compared
to “Sphyrna” gracile. Furthermore, the lower teeth of the former taxon have a narrower, taller and
strongly curved cusp compared to the lower teeth of the latter taxon. and the distal heel of the former
taxon is comparatively shorter than that of the latter taxon. The upper teeth of “Sphyrna” gracile
have a somewhat wider and more distally inclined main cusp compared to the upper teeth of extant S.
tudes. The lower teeth of the latter taxon are also narrower and more erect compared to those of the
former taxon.
Numerous Neogene fossil species have been assigned to Sphyrna, but our evaluation of the published
illustrations of the type or referred specimens leads us to conclude that most of them do not belong to
Sphyrnidae, let alone Sphyrna. For example, teeth identied as S. magna Cope, 1867, S. americana
Leriche, 1942, and S. lata Agassiz, 1843, among many others, are more appropriately identied as
Carcharhinus. Other examples include S. gilmorei Leriche, 1942, which has been placed in Negaprion
(i.e., Ebersole et al. 2019), and S. tortillis White, 1926 should be identied as Physogaleus.
Of the remaining Neogene species, Sphyrna arambourgi Cappetta, 1970, S. integra (Probst, 1878), and
S. laevissima (Cope, 1867) appear to be correctly identied as sphyrnids. The Lower Miocene S. integra
is based on one complete tooth and one partial tooth (see Pollerspöck & Unger 2023: pl. 11 gs 3–4),
but Cappetta (1970: pl. 19 gs 1–18) utilized a larger suite of Middle Miocene specimens to diagnose S.
arambourgi. Although the complete S. integra specimen shown by Pollerspock & Unger (2023: pl. 11
g. 3) appears to be a lower tooth with a clear separation of a mesial heel compared to the contiguous
convex mesial edge on S. arambourgi teeth, the latter taxon was synonymized with S. integra (Barthelt
et al. 1991). The teeth of “Sphyrna” gracile sp. nov. are like those of S. arambourgi and S. integra,
as illustrated by Cappetta (1970: pl. 19 gs 1–18) and Reinecke et al. (2011: pls 81–85), but there
are dierences between the Catahoula material and the two European taxa. For one, the main cusp of
S. arambourgi is somewhat narrower than that of “Sphyrna” gracile, particularly on lower teeth.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
41
Additionally, the mesial cutting edge on the upper teeth of S. arambourgi is straighter than that on the
Catahoula Formation teeth, which are weakly sinuous. Furthermore, the distal heel in S. arambourgi
and S. integra is short and sometimes weakly cuspidate, whereas in “Sphyrna” gracile sp. nov. the distal
heel is elongated and straight to weakly convex. Additionally, the mesial cutting edge of “Sphyrna”
gracile lower teeth has an angular appearance, whereas this edge is curved on comparable teeth of
S. arambourgi/S. integra (albeit sharply curved on the latter). Purdy et al. (2001) indicated that the
S. arambourgi morphology was similar to Mio-Pliocene teeth they referred to S. media, but they did not
specically synonymize the former with the latter.
Unfortunately, Cope (1867) did not include illustrations of teeth when he named the Galeocerdo
laevissimus morphology, but Leriche (1942) later assigned the morphology to Sphyrna. Purdy et al.
(2001: g. 60) gured Cope’s G. laevissimus type suite (Cope 1867), which shows that these teeth are
much larger in overall size (greater than 1 cm in mesio-distal width) and much more robust compared
to those of “Sphyrna” gracile sp. nov. Additionally, the very wide main cusp of the former species has
very convex mesial and distal cutting edges. The S. laevissima morphology is discussed further below.
Cicimurri & Knight (2009) reported a similar small and gracile hammerhead-like tooth morphology
from the Chandler Bridge Formation (Chattian) of South Carolina, which they assigned to Sphyrna
cf. media (following the observations of Purdy et al. 2001). Cicimurri et al. (2022) later identied
comparable teeth from the Ashley Formation (Rupelian) of South Carolina simply as Sphyrnidae
gen. et sp. indet. Examination of specimens from the Ashley (accession SC2007.36) and Chandler
Bridge (accession SC2005.2) formations indicate that the teeth are conspecic with “Sphyrna” gracile
sp. nov. Ebersole et al. (2024a) later described an isolated tooth as “Sphyrna” sp. that was derived from
the Rupelian Red Blu Clay in Alabama. This tooth has a shorter and wider main cusp and more convex
mesial edge than those of “Sphyrna” gracile.
Based on our evaluation of extant Sphyrna spp. dentitions, monognathic and dignathic heterodonty
are evident in our “Sphyrna” gracile sp. nov. sample. Teeth from anterior les are rather narrow and
have a more vertically directed cusp apex (Fig. 10A–B). In contrast, lateral teeth are wider and have
more distally inclined cusps (Fig. 10D–E). Additionally, in progressively more distal tooth les, cusp
inclination increases but overall cusp height decreases towards the commissure (compare Fig. 10J, H, D).
Dignathic heterodonty is reected in cusp width and the nature of the mesial cutting edge. Upper teeth
generally have a wider main cusp with a convex medial portion of the mesial cutting edge compared to
lower teeth (i.e., Fig. 10R vs A). In addition, the elongated mesial cutting edge of upper teeth may only
be slightly concave basally (Fig. 10O, L), but on lower teeth the basal one-half of the mesial edge is
clearly distinguished as an elongated, roughly horizontal heel (Fig. 10G, U).
The teeth of “Sphyrna” gracile sp. nov. dier from those of supercially similar carcharhiniform genera
within the Catahoula Formation, including Hemipristis, Galeorhinus, Physogaleus, and Galeocerdo,
by the lack of serrations and/or denticulations on the mesial and distal cutting edges. Although upper
teeth of Carcharhinus elongatus can be identied by the shallow notch on the mesial and distal sides
of the crown, only a distal notch occurs on the teeth of “Sphyrna” gracile. Lower teeth of “Sphyrna”
gracile have a conspicuously elongated mesial heel and root lobe, whereas the mesial and distal heels of
C. elongatus lower teeth are roughly equal in length.
“Sphyrna” robustum sp. nov.
urn:lsid:zoobank.org:act:36D0CA1E-07C4-4FF9-985D-8DC88A9280EB
Fig. 11
Diagnosis
”Sphyrna” robustum sp. nov. teeth dier from those of coeval ”Sphryna” gracile sp. nov. (see above)
by their greater stoutness, larger overall size, lower cusp height with respect to tooth size, and diering
European Journal of Taxonomy 984: 1–131 (2025)
42
shapes of the mesial cutting edge. These features also serve to distinguish “S.” robustum from the extinct
S. integra and S. arambourgi (see Cappetta 1970; Reinecke et al. 2011). Although morphologically
similar to “S.” robustum, fossil S. laevissima teeth have a more biconvex cusp and the mesial cutting
edge is conspicuously sinuous (Purdy et al. 2001: g. 60). Of presumed extant descendant species, the
teeth of S. mokarran and S. zygaena are comparable to those of “S.” robustum. However, the mesial
cutting edges of the new Oligocene species are less convex and lack serrations.
Etymology
The species name alludes to the stout appearance of the teeth.
Material examined
Holotype
UNITED STATES OF AMERICA – Mississippi • upper right lateral tooth; Catahoula Formation;
SC2013.28.171 (Fig. 11Q–S).
Paratypes
UNITED STATES OF AMERICA – Mississippi • lower right antero-lateral tooth; Catahoula Formation;
SC2013.28.169 (Fig. 11J–L) • lower right lateral tooth; Catahoula Formation; SC2013.28.167 (Fig.
11C–E).
Other material
UNITED STATES OF AMERICA – Mississippi • 82 isolated teeth; Catahoula Formation; SC2013.28.165
(22 teeth), SC2013.28.166 (Fig. 11A–B), SC2013.28.168, SC2013.28.170 (Fig. 11F–G), SC2013.28.172
(Fig. 11M–N), SC2013.28.173 to 28.176, SC2013.28.178, SC2013.28.179, SC2013.28.180 (Fig. 11O–P),
SC2013.28.181 (Fig. 11H–I), SC2013.28.182 (Fig. 11T–U), SC2013.28.183 (34 teeth), SC2013.28.184
(10 teeth), SC2013.28.915 (Fig. 11V–W), SC2013.28.916 (Fig. 11X–Y), SC2013.28.917 (Fig. 11Z–
AA).
Stratum typicum
Shelly, argillaceous sand of the Jones Branch fossil horizon, lower Catahoula Formation, Chattian Stage
(horizon no longer accessible).
Locus typicus
Site MS.77.011, Jones Branch, tributary owing into the Chickasawhay River, south of Waynesboro,
Wayne County, Mississippi, USA.
Description
The teeth are mesio-distally wider than high (apico-basally) in all jaw positions available, with specimens
measuring up to 12 mm in width but only a maximum of 8 mm in height. All teeth consist of a large
cusp and a distal heel. The mesial cutting edge can be straight, weakly sinuous, or concave, but it is
always smooth. On teeth with a sinuous cutting edge, the basal portion is concave, and the apical portion
is convex. The mesial edge of other teeth is uniformly concave, and the cusp apex is more vertically
directed. The distal cutting edge is much shorter than the mesial edge but is always smooth. This edge
is most often straight but may be weakly convex, and its orientation may be vertical or distally inclined.
The distal heel is low, elongated, and usually oblique, but may be horizontal. The cutting edge on the
distal heel is smooth and varies in convexity. This heel is usually separated from the distal cutting edge
by an indistinct notch. The root is bilobate, with the elongated lobes being widely divergent and their
lateral ends rounded. The basal margin of the root varies from slightly concave to virtually straight.
A thickened lingual root face is bisected by a deep nutritive groove.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
43
Remarks
The teeth of “Sphyrna” robustum sp. nov. dier from those of supercially similar carcharhiniform genera
within the Catahoula Formation, including Hemipristis, Galeorhinus, Physogaleus, and Galeocerdo, by
the lack of serrations and/or denticulations on the mesial and distal cutting edges. Although the upper
teeth of Carcharhinus elongatus have mesial and distal shoulders that may be weakly to moderately
serrated, these heels are distinctly separated from the main cusp by a shallow notch (only a distal notch
occurs in “Sphyrna” robustum). With respect to Rhizoprionodon, the teeth of “Sphyrna” robustum
achieve a much larger overall size and have a broader cusp.
“Sphyrna” robustum sp. nov. teeth dier from those of the coeval “Sphyrna” gracile sp. nov. by their
greater stoutness, larger overall size, lower cusp height with respect to tooth size, and diering shapes
of the mesial cutting edge. Most of these features also serve to distinguish the species from presumed
extant relatives, including Sphyrna lewini (SC2001.7.1), S. media (see Gilbert 1967), and S. tudes (see
Gilbert 1967). The teeth of “Sphyrna” robustum bear similarities to those in the jaws of extant Sphyrna
mokarran (SC2000.120.2) and S. zygaena (MSC 42600) that we examined, but on the Oligocene
specimens the mesial cutting edge of lower teeth is more concave than it is on upper teeth, and the
cutting edges are completely smooth on all specimens.
Fig. 11. “Sphyrna” robustum sp. nov., teeth. A–B. SC2013.28.166, upper right anterior tooth. A. Labial
view. B. Lingual view. C–E. SC2013.28.167 (paratype), lower right lateral tooth. C. Labial view.
D. Lingual view. E. Mesial view. F–G. SC2013.28.170, lower right anterior tooth. F. Labial view.
G. Lingual view. H–I. SC2013.28.181, upper right lateral tooth. H. Labial view. I. Lingual view.
J–L. SC2013.28.169, lower right antero-lateral tooth (paratype). J. Labial view. K. Lingual view.
L. Mesial view. M–N. SC2013.28.172, upper left lateral tooth. M. Labial view. N. Lingual view.
O–P. SC2013.28.180, upper left postero-lateral tooth. O. Labial view. P. Lingual view.
Q–S. SC2013.28.171 (holotype), upper right lateral tooth. Q. Labial view. R. Lingual view.
S. Mesial view. T–U. SC2013.28.182, lower left lateral tooth. T. Labial view. U. Lingual view.
V–W. SC2013.28.915, lower right lateral tooth. V. Labial view. W. Lingual view. X–Y. SC2013.28.916,
upper left lateral tooth. X. Labial view. Y. Lingual view. Z–AA. SC2013.28.917, lower right postero-
lateral tooth. Z. Labial view. AA. Lingual view. Scale bars = 3 mm.
European Journal of Taxonomy 984: 1–131 (2025)
44
The Catahoula Formation “Sphyrna” robustum sp. nov. teeth are comparable to the material that Cope
(1867) originally named as Galeocerdo laevissimus from the Miocene of Maryland. Leriche (1942)
later illustrated its morphology and placed it within Sphyrna (i.e., S. laevissima). Purdy et al. (2001:
g. 60) gured all the teeth within Cope’s G. laevissimus type suite and synonymized the taxon with
extant S. zygaena, citing similarities in gross morphology. Although Cope (1867) specically stated that
the cutting edges of the teeth he examined were smooth, Purdy et al. (2001) noted that tooth serrations
on fossil specimens became more prominent from the Miocene to the Pliocene, indicating phyletic
change within the taxon. However, Reinecke et al. (2011) later provided quantitative data separating the
laevissima morphology from that of S. zygaena. In any case, the “Sphyrna” robustum sp. nov. teeth dier
from both S. laevissima and S. zygaena by having narrower cusps and much less convex cutting edges
that are completely smooth. Ebersole et al. (2024a) reported an isolated tooth derived from the Rupelian
Red Blu Clay in Alabama that they conservatively assigned to “Sphyrna” sp.
Our evaluation of the dentitions of Sphyrna mokarran (SC2000.120.2) and S. zygaena (MSC 42600)
provides support for our conclusion that monognathic and dignathic heterodonty was developed in the
Catahoula Formation taxon. Anterior teeth have a rather narrow (mesio-distal) crown and somewhat erect
cusp (Fig. 11A), whereas teeth from more lateral positions are wider and have a more distally inclined
cusp (Fig. 11Q). The degree of distal inclination appears to have increased towards the commissure,
and at the same time overall tooth height decreased (Fig. 11O). Dignathic heterodonty is reected in the
narrowness of the tooth cusp, with upper teeth having a wider cusp (Fig. 11X) compared to lower teeth
(Fig. 11C). The variations in tooth shape and development of monognathic and dignathic heterodonty
would seem to provide a clear distinction between “Sphyrna” robustum sp. nov. and “S.” gracile
sp. nov. However, we also note that robust and gracile Sphyrna or Sphyrna-like tooth morphologies have
consistently been documented together within Oligo-Miocene strata. For example, following Purdy
et al. (2001), Cicimurri & Knight (2009) reported teeth of Sphyrna cf. media (small, narrow-cusped) and
S. zygaena (large, broad-cusped) from the Chattian Chandler Bridge Formation of South Carolina. Later,
Cicimurri et al. (2022) documented a small, narrow-cusped and a larger, broad-cusped Sphyrna-like
morphology for teeth from the Ashley Formation (Rupelian) of South Carolina that they simply referred
to Sphyrnidae gen. et sp. indet. based on the work of Lim et al. (2010) (see also Cappetta 1970; Purdy
et al. 2001; Carrillo-Briceño et al. 2016, 2019). Although these morphologies have been treated as
separate taxa (including herein), it could be interpreted that these morphologies actually represent other
forms of heterodonty within a single taxon.
As part of our analysis of these teeth, we considered the possibility that the “Sphyrna” gracile sp. nov.
(small, narrow-cusped) morphology represents ontogenetic and/or gynandric heterodonty within
S. robustum sp. nov. With respect to ontogenetic heterodonty, studies have demonstrated dietary shifts in
extant Sphyrna spp. from juvenile to adult growth stages (i.e., Gonzalez-Pestana et al. 2017). However,
little has been said about the changes, if any, in tooth shape during that shift. Mello & Brito (2013)
stated that ontogenetic heterodonty was “weak among sphyrnids” (p. 467). These authors examined
the embryonic teeth of Sphyrna tiburo (Linnaeus, 1758), S. tudes (Valenciennes, 1822), and Eusphyra
blochii (Cuvier, 1816) and found that there is an ontogenetic change in the anterior tooth les of these
taxa, but that lateral and posterior tooth les remain stable. Purdy et al. (2001) noted that the teeth of
juvenile/young adult S. zygaena have smooth cutting edges, whereas serrations occur on the teeth of
“large” individuals. This latter form of ontogenetic heterodonty is comparable to that documented in
Rhizoprionodon terraenovae, where tooth shape remains relatively constant from birth to adulthood, but
serrations develop on the teeth as the shark matures (Ebersole et al. 2023).
We examined the jaws of a juvenile and an adult Sphyrna lewini to determine whether ontogenetic
heterodonty occurs in this taxon. We found that tooth size in the upper les increases with age, but a
more conspicuous change is the orientation of the main cusp. For example, the fourth upper anterior
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
45
tooth of a juvenile S. lewini (MSC 50182) measures 6 mm in width and has a cusp that is 4 mm high and
3 mm wide, whereas the same adult tooth in MSC 42605 is 9 mm wide with a cusp that is 5 mm high and
4 mm wide. More telling, the distal cusp inclination of the juvenile tooth is 50° and on the adult tooth it
is 63°. These same changes are true for the seventh upper tooth le, with the tooth width of the juvenile
measuring 7.5 mm, cusp height 4 mm, cusp width 3.5 mm, and cusp inclination 44°. In contrast, the same
adult tooth is 11 mm wide with a cusp measuring 5 mm high and 4 mm wide, and cusp inclination is 58°.
Additionally, teeth in the rst upper le of both the juvenile and adult dentitions are comparable (roughly
symmetrical with a vertical cusp and well-dierentiated lateral heels), but the juvenile second tooth is
more similar to those of the succeeding les (distally inclined). In the adult dentition, the upper second
tooth is comparable to the tooth in the rst le. Our observations show that although there is an increase
in tooth size from juvenile to adult growth stages, a more signicant change is that the tooth cusps
become much more upright into adulthood. Considering our observations of dentitions of juvenile and
adult Sphyrna lewini, we believe that the morphological dierences between “Sphyrna” gracile sp. nov.
and “S.” robustum sp. nov. are too great for the morphologies to represent ontogenetic heterodonty.
Concerning gynandric heterodonty, Mello & Brito (2013) stated that “sexual heterodonty is hardly
developed” in Sphyrnidae. Although dierences in growth rates, age at maturity, and dietary preference
between male and female hammerhead sharks have been documented (Klimley 1987), to our knowledge
there is no published detailed description of gynandric variation within a given species. We herein
treat the two Catahoula Formation “Sphyrna” spp. morphologies as taxonomically distinct because our
samples do not appear to exhibit any morphological overlap in overall size, main cusp width, cutting
edge shape, or presence/absence of serrations.
Family Galeocerdonidae Poey, 1875
Genus Galeocerdo Müller & Henle, 1837
Type species
Squalus cuvier Péron & Lesueur in Lesueur, 1822, Extant.
Galeocerdo platycuspidatum sp. nov.
urn:lsid:zoobank.org:act:AA878AB5-B515-4297-97B0-2902357D5FEC
Fig. 12
Diagnosis
The teeth of the new Oligocene species are distinguished by the combination of a very wide cusp with
respect to crown width (cusp width comprises an average of 51% of total tooth width), a highly convex
mesial cutting edge, a convex distal cutting edge, an obtuse distal angle (formed by the intersection of
the distal cutting edge and distal heel), and a high distal heel (in lingual view) that is straight to only
weakly concave. Of the six fossil species currently recognized, the teeth of the new taxon dier from
the teeth of the Neogene Galeocerdo aduncus (Agassiz, 1843) by attaining larger overall sizes, having
greater overall crown height and a comparatively smaller but wider cusp, and by having a more obtuse
angle between the distal cutting edge and distal heel. Galeocerdo platycuspidatum sp. nov. teeth dier
from those of the Neogene Galeocerdo capellini Lawley, 1876 by having a mesio-distally wider cusp,
a more convex mesial cutting edge, and a distal angle of 90°. These teeth dier from the Eocene G.
clarkensis White, 1956 by having a mesial swelling on the cutting edge (as opposed to being evenly
convex), coarser serrations, and a wider distal angle (which is less than 90° in G. clarkensis). Galeocerdo
platycuspidatum teeth are supercially similar to those of the Eocene G. eaglesomei White, 1955
but are easily separated by having compound (as opposed to simple) serrations. Finally, Galeocerdo
European Journal of Taxonomy 984: 1–131 (2025)
46
platycuspidatum teeth can be dierentiated from those of the Miocene G. mayumbensis Dartevelle &
Casier, 1943 by having a wider cusp, a (generally) more convex mesial cutting edge, and a higher and
less concave distal cutting edge.
Etymology
The species name alludes to the mesio-distally wide cusp with a rather at labial face.
Material examined
Holotype
UNITED STATES OF AMERICA – Mississippi • antero-lateral tooth; Catahoula Formation; MMNS
VP-6622.2 (Fig. 12H–J).
Paratypes
UNITED STATES OF AMERICA – Mississippi • anterior tooth; Catahoula Formation; MMNS VP-
6622.1 (Fig. 12A–C) • postero-lateral tooth; Catahoula Formation; MMNS VP-12050 (Fig. 12Y–AA).
Other material
UNITED STATES OF AMERICA – Mississippi • 43 isolated teeth; Catahoula Formation; MMNS VP-
6622 (29 teeth), MMNS VP-6622.3 (Fig. 12K–L), MMNS VP-6622.4 (Fig. 12O–P), MMNS VP-6622.5
(Fig. 12W–X), MMNS VP-6622.6 (Fig. 12U–V), MMNS VP-6622.7 (Fig. 12Q–R), MMNS VP-6622.8
(Fig. 12M–N), MMNS VP-12049 (Fig. 12F–G), MMNS VP-12051 (Fig. 12S–T), MMNS VP-12052
(Fig. 12D–E), SC2013.28.109 to 28.113.
Stratum typicum
Shelly, argillaceous sand of the Jones Branch fossil horizon, lower Catahoula Formation, Chattian Stage
(horizon no longer accessible).
Locus typicus
Site MS.77.011, Jones Branch, tributary owing into the Chickasawhay River, south of Waynesboro,
Wayne County, Mississippi, USA.
Description
The teeth are broad-based and vary in overall height, with the largest specimens measuring up to 23 mm
in mesio-distal width and 25 mm in apico-basal height. The labial crown face is virtually at, but the
lingual face is convex, and enameloid on both faces is smooth. In mesial view, the crown has a slight
labial curvature. The basal one-half of the elongated mesial cutting edge can be convex (Fig. 12A),
slightly concave (Fig. 12H), or nearly straight (Fig. 12F). However, the upper one-half to one-third of
the mesial cutting edge is strongly convex and forms a conspicuous medial swelling (Figs 12O). This
cutting edge is serrated, and the serrations are typically very coarse along the lower three-quarters of
the cutting edges but become ner towards the crown apex (Fig. 12K). The distal cutting edge is much
shorter, weakly convex but may be straight, usually lingually inclined but may be vertical, and serrated.
The distal edge serrations are of the same size as or slightly smaller than those occurring on the apical
portion of the mesial edge. The mesial and distal cutting edges converge apically to form a very broad,
pointed cusp that is distally inclined to varying degrees. Serrations of both cutting edges extend virtually
to the cusp apex. An elongated distal heel forms an obtuse angle with the distal cutting edge (i.e.,
Fig. 12I, T). The heel is oblique and can bear more than 12 denticles, which decrease in size towards the
distal margin. The cutting edges on the denticles are serrated on the apical portion and often on the basal
portion (i.e., Fig. 12D). The root is bilobate with sub-rectangular lobes that vary in length and degree of
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
47
divergence. The lobes are separated by a deep V-shaped to shallow U-shaped interlobe area (compare
Fig. 12G to R). Root lobe extremities may be rounded or pointed. A low lingual boss bears a long, wide,
and shallow nutritive groove (Fig. 12K).
Remarks
Monognathic and ontogenetic heterodonty are evident in our sample based on jaws of extant Galeocerdo
cuvier (Péron & Lesueur in Lesueur, 1822) that we examined (SC2000.120.10, SC2020.53.4,
SC2020.53.18, MSC 42597, MSC 42624). Teeth that are slightly asymmetrical represent symphyseal
les (Fig. 12D–E). Specimens that are roughly as high as wide, have a somewhat angular to very
convex mesial edge, and have a vertically oriented cusp are considered anterior teeth (Fig. 12A, K).
Teeth that are more mesio-distally elongated, have a more convex mesial cutting edge, and have a
strongly distally directed cusp are lateral teeth (Fig. 12O, Q). Overall, crown height decreases and cusp
inclination increases towards the commissure (compare Fig. 12H, O, W, U). Some of the teeth in our
sample (Fig. 12O) are comparable in size to those in the jaws of a 300 kg female of G. cuvier represented
by SC2000.120.10.
Fig. 12. Galeocerdo platycuspidatum sp. nov., teeth. A–C. MMNS VP-6622.1 (paratype), anterior tooth.
A. Labial view. B. Lingual view. C. Mesial view. D–E. MMNS VP-12052, symphyseal tooth. D. Labial
view. E. Lingual view. F–G. MMNS VP-12049, anterior tooth. F. Labial view. G. Lingual view.
H–J. MMNS VP-6622.2 (holotype), anterior tooth. H. Labial view. I. Lingual view. J. Mesial view.
K–L. MMNS VP-6622.3, anterior tooth. K. Labial view. L. Lingual view. M–N. MMNS VP-6622.8,
anterior tooth. M. Labial view. N. Lingual view. O–P. MMNS VP-6622.4, lateral tooth. O. Labial view.
P. Lingual view. Q–R. MMNS VP-6622.7, lateral tooth. Q. Labial view. R. Lingual view. S–T. MMNS
VP-12051, anterior tooth. S. Labial view. T. Lingual view. U–V. MMNS VP-6622.6, posterior tooth.
U. Labial view. V. Lingual view. W–X. MMNS VP-6622.5, postero-lateral tooth. W. Labial view.
X. Lingual view. Y–AA. MMNS VP-12050 (paratype), posterior tooth. Y. Labial view. Z. Lingual view.
AA. Mesial view. Scale bars = 1 cm.
European Journal of Taxonomy 984: 1–131 (2025)
48
Ontogenetic heterodonty is not only expressed as a dierence in overall size among the teeth in our
sample, but larger teeth of presumed adults have coarser serrations on the mesial cutting edge and more
denticles on the distal heel compared to smaller (juvenile) teeth. Additionally, compound serrations
are better developed on large teeth, with additional serrae occurring on the apical and basal edges of a
serration, as opposed to only on the basal side on small teeth. A similar phenomenon was observed on
the distal heel, where denticles of larger teeth bear serrae on the apical and basal edges of a denticle,
but serrations are only on one edge of denticles on the smaller teeth. Galeocerdo teeth in the Catahoula
Formation are characterized by the combination of coarse compound serrations on the mesial and distal
cutting edges and a denticulated (with serrations) distal heel, features that are lacking on supercially
similar teeth of Physogaleus, Galeorhinus, Hemipristis, and “Sphyrna” that occur in the Catahoula
Formation.
We also attempted to determine whether dignathic heterodonty was developed in the Catahoula Formation
Galeocerdo. We observed slight dignathic heterodonty in the extant G. cuvier jaws we examined, and
“broad-toothed” (upper) and “narrow-toothed” (lower) morphologies have been attributed to extinct
G. aduncus (Agassiz, 1835) (i.e., Türtscher et al. 2021). For G. cuvier, we found that cusp width
(measured from the base of the distal edge to the opposite side on the mesial edge, parallel to the labial
crown foot) did not vary between upper and equivalent lower teeth. However, cusp length (measured
along the distal cutting edge) on upper teeth was 1.5 mm to 2 mm longer than their lower counterparts.
With respect to the Catahoula Formation Galeocerdo, the cusp width and height of all teeth measured
varies slightly between 9 and 11 mm, and between 6 and 7 mm, respectively, and this overlap precluded
the distinction of isolated upper teeth from lower teeth. However, the medial portion of the mesial
cutting edge on extant G. cuvier upper anterior teeth is very convex, whereas the mesial edge of lower
teeth is more uniformly convex. Our Catahoula Formation sample includes similar morphologies, and
we believe that teeth like those shown in Fig. 12H, O, and F are upper teeth, whereas those shown in
Fig. 12A, Q, and S are lower teeth.
Six Galeocerdo species are recognized in the fossil record (including G. cuvier; Türtscher et al. 2021),
and two of these, G. eaglesomei White, 1955 and G. clarkensis White, 1956, have been documented from
Eocene strata in the Gulf Coastal Plain (Ebersole et al. 2019). Teeth of G. eaglesomei are supercially
similar to those of Galeocerdo platycuspidatum sp. nov., but the latter have compound (as opposed
to simple) serrations and a larger cusp. Although multiple authors identied other Eocene teeth from
Alabama as G. latidens (see Tuomey 1858; Westgate 2001; Feldmann & Portell 2007; Clayton et al.
2013; Cappetta & Case 2016), this taxon is (at least in part) synonymous with G. eaglesomei (Ebersole
et al. 2019; Türtscher et al. 2021).
The mesial cutting edge on G. clarkensis teeth is more evenly convex, lacks a conspicuous medial
swelling on the mesial cutting edge, and has ner serrations compared to the Catahoula Formation
teeth. Additionally, the distal angle on G. clarkensis teeth is 90° or less, whereas the angle is obtuse on
G. platycuspidatum sp. nov. teeth (except on postero-lateral teeth, where it is approximately 90°).
The morphological features of Galeocerdo platycuspidatum sp. nov. teeth are like those of the Miocene
G. mayumbensis Dartevelle & Casier, 1943, but examination of the type specimens originally gured
(Darteville & Casier 1943: pl. 12 gs 22–29) indicates that the two are not conspecic. The cusp
in Galeocerdo platycuspidatum is much wider, the mesial cutting edge is generally more convex,
the distal cutting edge is usually convex, and the distal heel is higher but less concave compared to
G. mayumbensis. Unfortunately, only two of the teeth shown by Dartevelle & Casier (1943: gs 25, 29)
are complete and could be measured to determine the proportion of cusp width to tooth width. Those
two teeth appear to be similar to those we show in Fig. 12G and I, and when compared to each other the
G. mayumbensis teeth have a cusp that represents an average of 46% of total tooth width, whereas for
G. platycuspidatum this proportion is 51%.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
49
The temporal occurrence of the Catahoula Formation specimens is also older than the typically
Miocene records of G. mayumbensis (see also Perez 2022). The Catahoula Formation teeth are
similar to specimens that Müller (1999) identied as a new species, G. casei, from the Oligo-Miocene
Belgrade Formation of North Carolina. However, this taxon has been placed in synonymy with
G. mayumbensis (Andrianavalona et al. 2015; Türtscher et al. 2021). Müller’s gured specimens (Müller
1999: pl. 11 gs 1–4) have a mesio-distally narrow cusp closer to that of G. mayumbensis as opposed to
G. platycuspidatum sp. nov. Only three of the four teeth shown by Müller (1999) are complete, and the
cusp width of these specimens averages 42% of total tooth width, signicantly lower than the average
for G. platycuspidatum (51%).
Ebersole et al. (2024a) identied two teeth from the earliest Oligocene (lowermost Rupelian)
Red Blu Clay in Alabama as Galeocerdo sp. These teeth have compound serrations like those of
G. platycuspidatum sp. nov., but the mesial cutting edge of the former is more evenly (and less) convex
than on the latter. Additionally, the distal heel denticles of the Red Blu Clay specimens are very large
considering the relatively small tooth size, and the main cusp is narrower and more elongated compared
to that of G. platycuspidatum. Ebersole et al. (2024a) postulated that the Red Blu Clay teeth may
represent an undescribed earliest Oligocene taxon, which is congruent with the hypothesis that Cenozoic
tiger shark diversity is greater than presently recognized (Türtscher et al. 2021).
Cicimurri & Knight (2009) and Cicimurri et al. (2022) reported teeth of Galeocerdo aduncus (Agassiz,
1843) from the Chattian Chandler Bridge Formation and the Rupelian Ashley Formation, respectively,
of South Carolina. The Catahoula Formation specimens dier signicantly from the South Carolina
specimens by attaining larger overall sizes, having greater overall crown height and a comparatively
smaller but wider cusp, and the angle formed between the distal cutting edge and distal heel is obtuse.
In contrast, this angle is 90º or less in G. aduncus, and the distal heel is clearly separated from the distal
cutting edge by a distinct notch. Furthermore, the serrations of the Catahoula Formation Galeocerdo are
larger and more complex compared to the South Carolina Oligocene teeth.
Galeocerdo capellini Lawley, 1876 is based on a single tooth, but if considered valid both this taxon
and G. cuvier dier from G. platycuspidatum sp. nov. by having a mesio-distally narrower cusp, a less
convex mesial cutting edge, and the distal angle is 90° or less.
Division Batomorphi Cappetta, 1980b
Order Rhinopristiformes Naylor et al., 2012
Family Rhinidae Müller & Henle, 1841
Genus Rhynchobatus Müller & Henle, 1837
Type species
Rhinobatus laevis Bloch & Schneider, 1801, Extant.
Rhynchobatus cf. pristinus (Probst, 1877)
Fig. 13G–L
Xxx pristinus Probst, 1877: 81–82.
Material examined
UNITED STATES OF AMERICA – Mississippi • 246 isolated teeth; Catahoula Formation; MMNS
VP-7747 (16 teeth), MMNS VP-7754 (33 teeth), MMNS VP-12078, SC2013.28.494, SC2013.28.495,
European Journal of Taxonomy 984: 1–131 (2025)
50
SC2013.28.496 (Fig. 13G–I), SC2013.28.497 to 28.499, SC2013.28.500 (Fig. 13J–L), SC2013.28.501,
SC2013.28.502, SC2013.28.503 (7 teeth), SC2013.28.504 (17 teeth), SC2013.28.505 (7 teeth),
SC2013.28.506 (14 teeth), SC2013.28.507 (20 teeth), SC2013.28.508 (42 teeth), SC2013.28.509 (28
teeth), SC2013.28.510 (15 teeth), SC2013.28.511 (36 teeth), SC2013.28.526.
Description
In occlusal view, the main body of the tooth crown is usually wider than long, with larger specimens
measuring 4 mm in mesio-distal width. The occlusal outline of these teeth is sub-rectangular, with
the labial margin being convex and the sides straight or slightly angled medially (Fig. 13H, K). Some
teeth have a circular occlusal outline. The labial and lingual faces are separated by a transverse crest
Fig. 13. Pristis sp. (A–F, M–R), Rhynchobatus cf. pristinus (Probst, 1877) (G–L), and Anoxypristis sp.
(S–X), teeth and rostral spines. A–C. SC2013.28.490, Pristis sp., tooth. A. Oro-lingual view. B. Labial
view. C. Prole view. D–F. SC2013.28.486, Pristis sp., tooth. D. Oro-lingual view. E. Labial view.
F. Prole view. G–I. SC2013.28.496, Rhynchobatus cf. pristinus, tooth. G. Labial view. H. Occlusal
view. I. Prole view. J–L. SC2013.28.500, R. cf. pristinus, tooth. J. Labial view. K. Occlusal view.
L. Prole view. M–O. MMNS VP-12070, Pristis sp., right rostral spine. M. Basal view. N. Posterior
view. O. Dorsal view. P–R. MMNS VP-7787.1, Pristis sp., right rostral spine. P. Basal view. Q. Posterior
view. R. Dorsal view. S–U. MMNS VP-12071, Anoyxpristis sp., right rostral spine. S. Basal view.
T. Posterior view. U. Dorsal view. V–X. MMNS VP-12072.1, Anoxypristis sp., right rostral spine.
V. Basal view. W. Posterior view. X. Dorsal view. Scale bars: A–F = 1 mm; G–L = 3 mm; M–X = 1 cm.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
51
that varies in size, and the convex labial face is coarsely tuberculated (Fig. 13G–H). These tubercles
sometimes appear to coalesce into discontinuous ridges. The apical part of the lingual surface is at
and has a triangular outline, and unworn teeth have a tuberculated appearance. This surface transitions
to a smooth, convex portion of the lingual face. The sides of the lingual crown foot are formed into
thin, shelf-like projections. There is a pronounced medial uvula that extends onto the root surface. The
uvula may be short and wide or narrow and elongated (compare Fig. 13H to K). In prole view, the
labial crown foot overhangs the low root, and the root extends slightly beyond the lingual crown foot
(Fig. 13I, L). In basal view, the root is obviously bilobate, with the somewhat triangular lobes being
separated by a longitudinal nutritive groove. The basal attachment surfaces are at to weakly convex. In
occlusal view, the root bears margino-lingual foramina that ank the crown uvula, and the lingual root
projection has a notched appearance.
Remarks
Various tooth sizes and slightly diering morphologies occur in our sample, but we attribute these
minor dierences to heterodonty. Specimens with a circular occlusal outline may represent symphyseal
or anterior positions and those with a more rectangular outline are from lateral les (monognathic
heterodonty). Variation in tooth size could reect ontogenetic heterodonty (i.e., juvenile versus adult
individuals) or even dignathic heterodonty, given the unusual conguration of the Rhynchobatus dentition
(see Dean et al. 2017: gs 1–2). Crown ornamentation is dicult to discern on many specimens, which
in part is the result of post mortem ablation (i.e., current transport) but also in vivo wear (which is
particularly evident at the crown apex).
These teeth are signicantly larger and more robust than those of Pristis sp., described below, and they
possess labial ornamentation but lack lingual lateral uvulae. Cicimurri & Knight (2009) reported four
teeth from the Chattian Chandler Bridge Formation of South Carolina that they tentatively identied as
Rhynchobatus pristinus, and the species was noted in the Oligocene Old Church Formation of Virginia
(Müller 1999) and the Oligo-Miocene Belgrade Formation of North Carolina (Case 1980; Müller 1999).
Cicimurri et al. (2022) reported a few teeth from the Rupelian Ashley Formation that were identied as
Rhynchobatus sp. Most of the Catahoula Formation specimens are ablated, but well-preserved teeth fall
within the range of variation of R. pristinus and are tentatively referred to that species. Rhynchobatus
pristinus apparently had a wide distribution in the Western Hemisphere (Cappetta 1970; Laurito
1999; Ward & Bonavia 2001; Vialle et al. 2011; Fialho et al. 2019), but the specimens noted in the
aforementioned reports are variable and it remains to be determined whether all of these records are
accurately attributed to R. pristinus. It is interesting to note that all of the Oligocene records known
to us are from the Atlantic Coastal Plain of the USA, and the teeth in our sample represent the rst
occurrences of fossil Rhynchobatus in the Gulf Coastal Plain of the USA.
Family Pristidae Bonaparte, 1838
Genus Pristis Linck, 1790
Type species
Squalus pristis Linnaeus, 1758, Extant.
Pristis sp.
Fig. 13A–F, M–R
Material examined
UNITED STATES OF AMERICA – Mississippi • 12 rostral spines; Catahoula Formation; MMNS VP-
7787 (5 specimens), MMNS VP-7787.1 (Fig. 13P–R), MMNS VP-12070 (Fig. 13M–O), SC2013.28.515,
European Journal of Taxonomy 984: 1–131 (2025)
52
SC2013.28.516, SC2013.28.517 (3 specimens) • 28 isolated teeth; Catahoula Formation; MMNS VP-
7748 (4 teeth), MMNS VP-8744 (2 teeth), MMNS VP-9211 (4 teeth), SC2013.28.486 (Fig. 13D–F),
SC2013.28.487 to 28.489, SC2013.28.490 (Fig. 13A–C), SC2013.28.491 (4 teeth), SC2013.28.492
(3 teeth), SC2013.28.493 (4 teeth), SC2013.28.512, SC2013.28.527.
Description
The rostral spines are composed entirely of dentine. These spines are elongated, antero-posteriorly
narrow, and dorso-ventrally attened but thick. The anterior and posterior margins are parallel along
most of the spine length, but near the distal tip, the anterior margin converges towards the posterior
margin to form a sharp point. The anterior margin is rounded except at the distal tip, which is a sharp
edge. The posterior margin bears a furrow along its entire length. The dorsal and ventral surfaces are
weakly convex except at the distal tip, where the surfaces are at. Fine growth lines are visible near the
base, and the basal surface has a somewhat D-shaped outline (Fig. 13M, P).
The teeth are tiny, measuring 1 mm in total height. Crown width (mesio-distal) averages 1.2 mm,
with the smallest measuring 1.0 mm and the largest 1.8 mm in this dimension. Crown length averages
1.1 mm, with the smallest measuring 0.8 mm and the largest 1.5 mm in this dimension. The teeth are
somewhat globular in appearance, with a crown that is convex in labial and prole views (Fig. 13B,
E–F). In occlusal view, a transverse crest divides the crown into labial and lingual parts (Fig. 13D). The
crest is generally blunt but can be sharp, and it does not reach the foot of the lateral crown. In labial view,
the crest can be at and weakly cuspidate with a pointed apex. The labial crown margin is weakly to
strongly convex, and the labial face is convex to varying degrees. The lingual face exhibits an elongate
medial protuberance (i.e., uvula) that extends onto the root, and this protuberance varies in width and
length. The distal ends of the crown are lingually directed and form a roughly 70º angle with the medial
lingual uvula (Fig. 13A, D). The angularity of the lateral crown projections varies from narrow and
pointed to wide and rounded. The crown slightly overhangs the root labially, but the root extends beyond
the lateral and lingual crown faces (Fig. 13A, C, E). In basal view, the root is bisected by a wide nutritive
groove that is perforated (medially) by several small foramina. The root lobes are very short in prole
view and have a cleaver-shaped basal outline, with a distinctive narrow process extending lingually. The
oral root surface bears a pair of large foramina, one on each side of the medial uvula.
Remarks
Although all the rostral spines are ablated, they compare well to spines in the rostra of extant Pristis
pectinata Latham, 1794 (MSC 43849, MSC 43850, SC90.80.1) that we examined. Some of the
Catahoula Formation spines have a sharp antero-distal margin and oblique striations on the dorsal
and ventral surfaces. These features were observed on extant Pristis spines and have been reported on
Eocene specimens, and they indicate that the Catahoula sawshes used their spined rostrum to probe
the sandy substrate for prey (Cicimurri 2007; Ebersole et al. 2019). It is interesting to note that the
gured specimens exhibit a distinct transition from sub-parallel margins to gently apically converging
(Fig. 13O, R). Some rostral spines exhibiting this morphology reported from elsewhere have been
assigned to Pristis brayi Casier, 1949 (see Hovestadt & Steurbaut 2023: 88). However, our examination
of several extant Pristis spp. rostra demonstrates that the beginning of this constriction represents
the point where the spine was exposed from the rostrum, with the proximal end set within a deep
alveolus of the rostral cartilage (the distal end is exposed to wear). Ebersole et al. (2019) discussed
the taxonomic uncertainty involved with the speciation of isolated Paleogene Pristis spines, and we
herein follow these authors by leaving the Catahoula Formation specimens within open nomenclature. It
cannot be ascertained whether similar rostral spines reported from middle Eocene deposits in Alabama
(Cappetta & Case 2016; Ebersole et al. 2019) are conspecic with the Catahoula Formation taxon, or if
multiple Paleogene taxa are present.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
53
The familial/generic assignment of teeth like those described above has been debated over the past
several years, with alternating assignments to Rhinobatidae/Rhinobatos and Pristidae/Pristis (i.e.,
Cappetta & Case 2016; Ebersole et al. 2019; Adnet et al. 2020), but all sources agree that the morphology
is assignable to Rhinopristiformes. Reinecke et al. (2023) provided a monograph that helped us make
a more informed identication of these fossil teeth. The Catahoula Formation teeth are wider (mesio-
distally) than long (labio-lingually). Additionally, the transverse crest, which ranges from low and
rounded to sharp and cuspidate, has a straight to sinuous appearance (in occlusal view). Although the
lateral crown margins are lingually directed and extend beyond the lingual medial uvula, we do not view
these structures as lateral uvulae (sensu Cappetta 2012). Furthermore, in prole view the oral surface
of the lingual medial uvula has a weakly to strongly sinuous outline, depending on the height of the
transverse crest and the convexity of the uvula itself.
The features we observed on the Catahoula Formation teeth described above are consistent with those of
fossil and extant representatives of Pristis (Cappetta 2012; Carrillo-Briceño et al. 2015, 2016; Reinecke
et al. 2023). These features include a sinuous transverse crest and a lack of lateral uvulae (in occlusal
view), as well as the sinuous oral margin of the medial lingual uvula and slight labial overhang of the
root (in prole view). Additionally, the basal root surface is cleaver-shaped with a distinctively lingually
elongated projection.
In contrast, teeth of the extant rhinobatids Pseudobatos horkelii (Müller & Henle, 1841) and Glaucostegus
cemiculus (Georoy Saint-Hilaire, 1817) have distinctive labial and lingual portions of the crown (see
Reinecke et al. 2023: pls 13, 17) like the fossil teeth of Rhynchobatus we observed (see above). Although
teeth of the extant Rhinobatos annandalei Norman, 1926 and Acroteriobatus annulatus (Smith in
Müller & Henle, 1841) are similar to our Catahoula Formation specimens, they dier by having a
straight transverse crest (occlusal view), a generally convex oro-lingual margin and a shorter, more
oblique medial lingual uvula (prole view), a greater labial overhang of the root (prole view), and a
shorter lingual projection of the root (basal view). These dierences can be observed among the teeth
shown by Reinecke et al. (2023: pls 1–4, 9–10, 5–16).
There are slight variations in tooth morphology within our Catahoula Formation sample that likely
reect some form of heterodonty. Narrow teeth with sharp and generally cuspidate transverse crests may
represent anterior jaw positions, whereas teeth that are conspicuously wider than long with a low and
rounded transverse crest may have been from lateral les.
Genus Anoxypristis White & Moy-Thomas, 1941
Type species
Pristis cuspidatus Latham, 1794, Extant.
Anoxypristis sp.
Fig. 13S–X
Material examined
UNITED STATES OF AMERICA – Mississippi • 10 rostral spines; Catahoula Formation; MMNS
VP-12071 (Fig. 13S–U), MMNS VP-12072 (7 specimens), MMNS VP-12072.1 (Fig. 13V–X),
SC2013.28.514.
European Journal of Taxonomy 984: 1–131 (2025)
54
Description
The spines are elongated, very thin dorso-ventrally (Fig. 13T, W), with a triangular dorsal outline. The
anterior and posterior faces are thin and converge distally to form a medially located point (Fig. 13U,
X). The basal surface may have an elliptical or teardrop-shaped (rounded anterior margin but tapering
posteriorly) outline (Fig. 13S, V).
Remarks
These spines are comparable to those occurring on a rostrum of extant Anoxypristis sp. that we examined
(SC86.214.1). They dier from the spines of the Catahoula Formation Pristis sp. (see above) and those
of extant Pristis (i.e., MSC 43849, MSC 43850, SC90.80.1) by being much thinner dorso-ventrally
(although Pristis spines are very thin at the pointed distal end), having rather thin anterior and posterior
faces, and having an elliptical to teardrop-shaped basal outline. In contrast, the fossil Pristis sp. spines
are comparably thicker, very elongated but narrow antero-posteriorly, the posterior surface is concave,
and the basal outline is “D” shaped. Although Cicimurri & Knight (2009) observed an Anoxypristis sp.
rostral spine from the Chandler Bridge Formation (Chattian, NP25) of South Carolina that was housed
in a private collection, sawsh specimens have yet to be formally described from the South Carolina
Oligocene. Anoxypristis spines of similar morphology to those from the Catahoula Formation have been
conrmed from middle Eocene deposits in Alabama (Cappetta & Case 2016; Ebersole et al. 2019), but
we cannot determine whether they are conspecic.
Order Myliobatiformes Compagno, 1973
Suborder Myliobatoidei Compagno, 1973
Family Dasyatidae Jordan & Gilbert, 1879
Genus Hypanus Ranesque, 1818
Type species
Raja say Lesueur, 1817, Extant.
Hypanus? heterodontus sp. nov.
urn:lsid:zoobank.org:act:DECAA150-D2AE-4591-BC8B-2EE90BF5D560
Figs 14–17, 18A–J
Diagnosis
Low-crowned teeth and high-crowned teeth are represented for this taxon. Low-crowned teeth generally
have a convex labial face (amount of convexity varies) with a transversely depressed area near the apex.
The labial face bears highly irregular ridges that are weakly to strongly developed and extend onto a
wide transverse crest. The lingual face is smooth and bears a medial longitudinal crest anked by lateral
depressed areas. The bilobate root is low, located closer to, and extending beyond, the lingual crown
margin. High-crowned teeth are cuspidate, with cusp height and degree of distal and lingual inclination
varying. A thin transverse crest subdivides the crown into a large lingual face and much smaller labial
face. The labial face may be virtually smooth but is usually ornamented with irregular and disconnected
vertical ridges, sometimes forming a reticulated network. The lingual face is smooth and exhibits a
medial longitudinal crest of varying width.
New fossil species of Hypanus have yet to be named, but fossil teeth of several extant species (formerly
placed in Dasyatis) have been reported. A small male tooth identied as H. americanus (Hildebrand &
Schroeder, 1928) from the lower Miocene Pungo River Formation of North Carolina has a much more
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
55
concave labial face and the lingual crown curvature is more pronounced apically than on Hypanus?
heterodontus sp. nov. teeth of similar stature (Purdy et al. 2001). However, this comparison may be
irrelevant, as we believe the Miocene tooth is that of a mobulid ray. Fitch (1966, 1970) reported a total
of 12 H. dipterurus (Jordan & Gilbert, 1880) teeth from Pleistocene deposits of California, but he did
not describe or illustrate them. Deynat & Brito (1994) reported caudal spines of H. guttatus (Bloch &
Schneider, 1801) from the Miocene of central South America, but no teeth were noted. Pliocene teeth
from the Yorktown Formation of North Carolina identied as H. say (Lesueur, 1817) by Purdy et al.
(2001) are smaller in overall size and more strongly ornamented compared to H.? heterodontus. However,
high-crowned teeth of living H. say have a more concave labial face and more strongly lingually curved
crown compared to H.? heterodontus, and the ornamentation on low-crowned teeth of the former species
does not extend onto the transverse crest as it does on teeth of the latter species (see Reinecke et al.
2023: pls 64–67).
Etymology
The species name refers to the variation in gross crown morphology and ornamentation.
Material examined
Holotype
UNITED STATES OF AMERICA – Mississippi • low-crowned tooth (Fig. 14P–T); Catahoula
Formation; SC2013.28.449.
Paratypes
UNITED STATES OF AMERICA – Mississippi • high-crowned tooth (Fig. 14F–J); Catahoula For-
mation; SC2013.28.406 • high-crowned tooth (Fig. 14K–O); Catahoula Formation; SC2013.28.409 •
low-crowned tooth (Fig. 14A–E); Catahoula Formation; SC2013.28.444.
Other material
UNITED STATES OF AMERICA – Mississippi • 574 isolated teeth; Catahoula Formation; MMNS VP-
7530 (16 teeth), MMNS VP-7749 (60 teeth), MMNS VP-7912, MMNS VP-8742, MMNS VP-12068,
MMNS VP- 12069, SC2013.28.407 (Fig. 17K–O), SC2013.28.408 (Fig. 16K–O), SC2013.28.410,
SC2013.28.411, SC2013.28.412 (Fig. 16F–J), SC2013.28.413 (Fig. 16P–T), SC2013.28.414 to
28.420, SC2013.28.421 (Fig. 17P–T), SC2013.28.422 (Fig. 16U–Y), SC2013.28.423 (Fig. 17U–
Y), SC2013.28.424 (Fig. 16A–E), SC2013.28.425 to 28.427, SC2013.28.428 (Fig. 16Z–DD),
SC2013.28.431 (19 teeth), SC2013.28.432 (5 teeth), SC2013.28.433 (8 teeth), SC2013.28.434 (5 teeth),
SC2013.28.435 (6 teeth), SC2013.28.436 (15 teeth), SC2013.28.437 (Fig. 15F–J), SC2013.28.438,
SC2013.28.439, SC2013.28.440 (Fig. 15K–O), SC2013.28.441 (5 teeth), SC2013.28.442 (7 teeth),
SC2013.28.443, SC2013.28.445 (Fig. 15P–T), SC2013.28.446 (19 teeth), SC2013.28.447 (15
teeth), SC2013.28.448, SC2013.28.450 (Fig. 15Z–DD), SC2013.28.451 to 28.454, SC2013.28.455
(Fig. 15U–Y), SC2013.28.456, SC2013.28.457, SC2013.28.458 (19 teeth), SC2013.28.459 (22 teeth),
SC2013.28.460, SC2013.28.461 (Fig. 15A–E), SC2013.28.462, SC2013.28.463, SC2013.28.464
(5 teeth), SC2013.28.465, SC2013.28.466 (Fig. 17A–E), SC2013.28.467 (6 teeth), SC2013.28.468
(11 teeth), SC2013.28.469, SC2013.28.470 (Fig. 17F–J), SC2013.28.471 to 28.473, SC2013.28.474
(4 teeth), SC2013.28.475 (Fig.18A–E), SC2013.28.476 (Fig. 18F–J), SC2013.28.477 (195 teeth)
SC2013.28.478 (55 teeth), SC2013.28.513, SC2013.28.523 (3 teeth), SC2013.28.524 (5 teeth),
SC2013.28.525 (15 teeth).
Stratum typicum
Shelly, argillaceous sand of the Jones Branch fossil horizon, lower Catahoula Formation, Chattian Stage
(horizon no longer accessible).
European Journal of Taxonomy 984: 1–131 (2025)
56
Locus typicus
Site MS.77.011, Jones Branch, tributary owing into the Chickasawhay River, south of Waynesboro,
Wayne County, Mississippi, USA.
Description
Two morphotypes are represented in the sample, namely low-crowned and high-crowned. Most of the
specimens of both morphotypes measure 1.5 mm or less in greatest width (mesio-distal), but a handful
of larger specimens (n = 11) measure between 2 mm and 3.2 mm in width.
The low-crowned morphotype has a somewhat six-sided occlusal outline but can appear to be diamond-
shaped. The crown width is slightly greater than the length. The mesial and distal ends of the crown
are angular (with the angles located somewhat labially), whereas the labial and lingual margins are
generally broader and have rounded to straight margins. In labial view, the crown base may be uniformly
convex (broadly or narrowly) or can be straight medially (compare Figs 15A, F, 17A). In prole view,
the labial face ranges from weakly to strongly convex, and a weak depression typically occurs within
the apical one-half of the crown (Figs 15E, J, 17E). The lingual margin may be straight but sloping
from the apex to the crown foot (Fig. 15DD), but most often it is sub-angular, such that there is a more
vertical portion transitioning basally to an elongated heel (Fig. 17J). There is a thick transverse crest
extending nearly to the crown foot of the mesial and distal sides (Figs 15H, 17J). The labial crown face is
ornamented to varying degrees, with the ornament ranging from occasional discontinuous and irregular
interconnected ridges (Fig. 15U) to extensive similar ornamentation forming a reticulated network
(Fig. 15A). The ornamentation does not reach the base of the crown foot (Fig. 15A, E), but it does
extend onto the apical surface on the lingual side of the transverse crest (Fig. 15C, G, M, Q). The lingual
crown face is otherwise smooth. The transverse crest is intersected by a lingual crest that ranges from
strong to inconspicuous (compare Fig. 15H to W). In prole view, the crown base is generally straight
(Fig. 15O), but the labial margin may extend basally beyond the origin of the root (Fig. 15DD). In basal
view, the enameloid extends to the aboral surface of the crown, and the root appears to emanate from a
basin framed by the enameloid (Figs 15D, 17I). The bilobate root is large, rather low, and located at the
lingual one-half of the tooth (Figs 15J, Y, 17E). The root lobes are separated by a wide and deep nutritive
groove, and the basal attachment surface is sub-triangular and at to weakly convex (Fig. 15I, N). Well-
preserved specimens show that the lobes extend beyond the lingual crown margin (Fig. 15J).
The high-crowned specimens measure up to 1.7 mm in crown height, and they have a sub-triangular
outline in occlusal view (Figs 16G, 17L). In this view, the lingual face is more extensive than the labial
face (Figs 16L, 17Q). The mesial and distal ends of the crown may be sharply angular or rounded
(compare Fig. 16G to AA), and these lateral angles are located closer to the labial margin (Fig. 16V). The
lingual margin is generally strongly and uniformly convex, but some specimens are embayed laterally.
The labial margin ranges from nearly straight to strongly convex (compare Figs 16L and 17V). In prole
view, the labial margin is convex to varying degrees (Figs 16J, 17T, Y). The cusp is conspicuous, and
on some specimens, it is strongly lingually inclined, such that the labial margin appears to be somewhat
angular (Fig. 17O). The lingual face is expansive and generally convex, although there are depressed
areas on both sides of the crown. The crown foot is extended into a short, straight to sloping shelf-like
structure, and the transition from cusp apex to lingual crown foot is strongly concave (Fig. 16E, Y). The
crown base may be straight, or the labial margin may extend somewhat basally beyond the origin of the
root (compare Fig. 16T to 17O). In occlusal (and prole) view, there is a thin transverse crest (close to
the labial margin) that extends the entire height of the cusp but does not reach the crown foot (Fig. 14G,
J). This crest forms the border of the labial face, which itself ranges from very weakly convex to slightly
concave (compare Fig. 16U to 17K). Additionally, the labial face is ornamented to varying degrees,
ranging from a few incomplete, sinuous vertical ridges (Fig. 17P) to more extensive and interconnected
ridges (Fig. 14K), and sometimes heavy ornamentation consisting of a weakly reticulated network of
ridges (Fig. 17U). The ornamentation never reaches the crown foot, which is formed by a rim of smooth
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
57
enameloid (Fig. 16K, Z). In labial view, the crown has a sub-triangular outline with the basal margin
being uniformly convex to varying degrees (compare Fig. 14K to 16Z) and the cusp being vertical to
distally inclined to varying degrees (compare Figs 14F, 16P, and 17P). Additionally, the mesial and
distal sides may be straight (Fig. 14F), slightly convex (Fig. 16F), concave (Fig. 17K), or evenly convex
on the mesial side but concave on the distal side (Fig. 17P). The transverse crest is intersected on the
lingual side by a broad longitudinal crest that does not reach the crown foot (Figs 14H, 16H, 17M). In
basal view, the enameloid extends to the aboral surface of the crown, and the root emanates from a basin
within the enameloid (Figs 16CC, 17N). The bilobate root is large and located at the distal one-half of
the tooth (Figs 14O, 16E). The lobes are separated by a wide and deep nutritive groove, and the basal
attachment surface is sub-triangular and at to weakly convex (Fig. 16N, S). Well-preserved specimens
show that the lobes extend beyond the lingual crown margin (Fig. 16O, T).
Fig. 14. Hypanus? heterodontus sp. nov., teeth (type specimens). A–E. SC2013.28.444 (paratype), low-
crowned tooth. A. Labial view. B. Occlusal view. C. Lingual view. D. Basal view. E. Prole view.
F–J. SC2013.28.406 (paratype), high-crowned tooth. F. Labial view. G. Occlusal view. H. Lingual view.
I. Basal view. J. Prole view. K–O. SC2013.28.409 (paratype), high-crowned tooth. K. Labial view.
L. Occlusal view. M. Lingual view. N. Basal view. O. Distal view. P–T. SC2013.28.449 (holotype),
low-crowned tooth. P. Labial view. Q. Occlusal view. R. Oro-lingual view. S. Basal view. T. Prole
view. Scale bars = 1 mm.
European Journal of Taxonomy 984: 1–131 (2025)
58
Fig. 15. Hypanus? heterodontus sp. nov., low-crowned teeth. A–E. SC2013.28.461. A. Labial view.
B. Occlusal view. C. Lingual view. D. Basal view. E. Prole view. F–J. SC2013.28.437. F. Labial
view. G. Occlusal view. H. Lingual view. I. Basal view. J. Prole view. K–O. SC2013.28.440.
K. Labial view. L. Occlusal view. M. Lingual view. N. Basal view. O. Prole view. P–T. SC2013.28.445.
P. Labial view. Q. Occlusal view. R. Lingual view. S. Basal view. T. Prole view. U–Y. SC2013.28.455.
U. Labial view. V. Occlusal view. W. Lingual view. X. Basal view. Y. Prole view. Z–DD. SC2013.28.450.
Z. Labial view. AA. Occlusal view. BB. Lingual view. CC. Basal view. DD. Prole view. Scale bars =
1 mm.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
59
Fig. 16. Hypanus? heterodontus sp. nov., high-crowned teeth. A–E. SC 2013.28.424. A. Labial view.
B. Occlusal view. C. Lingual view. D. Basal view. E. Prole view. F–J. SC2013.28.412. F. Labial
view. G. Occlusal view. H. Lingual view. I. Basal view. J. Prole view. K–O. SC2013.28.408.
K. Labial view. L. Occlusal view. M. Lingual view. N. Basal view. O. Prole view. P–T. SC2013.28.413.
P. Labial view. Q. Occlusal view. R. Lingual view. S. Basal view. T. Prole view. U–Y. SC2013.28.422.
U. Labial view. V. Occlusal view. W. Lingual view. X. Basal view. Y. Prole view. Z–DD. SC2013.28.428.
Z. Labial view. AA. Occlusal view. BB. Lingual view. CC. Basal view. DD. Prole view. Scale bars =
1 mm.
European Journal of Taxonomy 984: 1–131 (2025)
60
Remarks
The low-crowned dasyatid teeth described above are easily distinguished from those of Catahoula
Formation rhinopristiform rays (see above) by their roughly six-sided outline, extensive pitted crown
ornamentation, lack of lingual lateral protuberances (i.e., uvulae), and the overall morphology of the root.
There is extensive morphological variation within our sample of Catahoula Formation dasyatid teeth,
which we believe reects heterodonty within a single species. Extant dasyatid rays exhibit gynandric
heterodonty, where female and juvenile male teeth are low-crowned, but teeth of mature males are high-
crowned and cuspidate (Reinecke et al. 2023). The male high-crowned morphology develops during the
breeding season, when the pointed teeth are utilized to grasp onto a female during copulation (Kajiura
& Tricas 1996). Although the low- and high-crowned Catahoula Formation morphologies appear to be
disparate, the high-crowned teeth bear similar, although much reduced, ornamentation as occurs on low-
crowned specimens. Reinecke et al. (2023) provided excellent illustrations of dentitions of numerous
extant dasyatid taxa that demonstrate this phenomenon (i.e., compare their pls 70–72, 74), which is
also observed in the Catahoula Formation sample we examined. We therefore conclude that the high-
crowned morphology represents breeding teeth of mature males, whereas low-crowned teeth represent
immature or non-breeding male individuals or females.
With respect to the male cuspidate morphology, there is obvious variation in crown morphology that
indicates at least monognathic heterodonty. One specimen (Fig. 14F–J) has a tall, broad, and symmetrical
cusp that indicates it occupied a le close to the symphysis. Another specimen (Fig. 17K–O) has a tall,
narrow, and symmetrical crown that may reect an anterior tooth le. Most specimens have a relatively
short and distally inclined cusp, and we believe that they represent lateral tooth les. The tooth height
decreases, but cusp inclination increases towards the commissure (compare Figs 16K, P, 17P). This
interpretation is consistent with the morphological variation within extant dasyatid dentitions as shown
by Reinecke et al. (2023).
It is also possible that the Catahoula Formation sample reects dignathic heterodonty. For example,
tall and symmetrical cuspidate teeth may have been from the anterior portion of the lower dentition
(Fig. 16K), but asymmetrical teeth with relatively short cusps may have been from the upper symphyseal
region (Fig. 16U). With respect to crown width (mesio-distal) versus length (labio-lingual), upper teeth
may be broader than their lower jaw counterparts (i.e., compare Fig. 16H to 17L). Low-crowned teeth
of extant Hypanus say bearing a transverse apical depression on the labial face occur in the jaws of both
male and female individuals (i.e., Reinecke et al. 2023: pls 64–65), so this feature does not provide clarity
with respect to distinguishing upper from lower teeth of the Catahoula Formation species. However,
crown ornamentation within the upper dentition may be weaker than that of the lower dentition (compare
Fig. 15U to A).
The sample of Hypanus? heterodontus sp. nov. available to us includes small and large versions of low-
crowned teeth, all of comparable morphology, that we interpret as an ontogenetic increase in tooth size
within the new species. Most of the low-crowned teeth measure less than 1.6 mm in greatest width, but
some of the largest specimens measure 3.2 mm in this dimension. In occlusal view, these large teeth
have a diamond-shaped outline (Fig. 18A, F) and in prole view the labial face is convex to varying
degrees with an apically depressed area (Fig. 18D, I). Additionally, the labial ornamentation of the
larger teeth can consist of irregular interconnected ridges like that occurring on small low-crowned
teeth (compare Fig. 18B to 15A). Lastly, the crown ornamentation on large teeth extends onto the apical
part of the lingual side of the transverse crest (Fig. 18C, H). All the features of the large teeth can also
be observed on the smaller teeth (i.e., compare Fig. 18A–J to specimens in Fig. 15), and we therefore
consider the specimens to be conspecic.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
61
The overall crown shapes of the low- and high-crowned teeth, as well as the morphological variation
we observed within the Catahoula Formation sample, are consistent with extant Hypanus say as shown
by Reinecke et al. (2023). The various forms of heterodonty expressed in H. say also appear to provide
the best model with which to compare the Catahoula Formation species. We tentatively assign the new
species to Hypanus Ranesque, 1818, to indicate close similarities to extant Hypanus teeth and take
Fig. 17. Hypanus? heterodontus sp. nov., teeth. A–E. SC2013.28.466, low-crowned tooth. A. Labial
view. B. Occlusal view. C. Lingual view. D. Basal view. E. Prole view. F–J. SC2013.28.470, low-
crowned tooth. F. Labial view. G. Occlusal view. H. Lingual view. I. Basal view. J. Prole view.
K–O. SC2013.28.407, high-crowned tooth. K. Labial view. L. Occlusal view. M. Lingual view.
N. Basal view. O. Prole view. P–T. SC2013.28.421, high-crowned tooth. P. Labial view. Q. Occlusal
view. R. Lingual view. S. Basal view. T. Prole view. U–Y. SC2013.28.423, high-crowned tooth.
U. Labial view. V. Occlusal view. W. Lingual view. X. Basal view. Y. Prole view. Scale bars = 1 mm.
European Journal of Taxonomy 984: 1–131 (2025)
62
into consideration the possibility that the extinct species belongs to an unrecognized genus within the
Hypanus lineage. Although Hypanus was not included in their study of batoid diversication, Puckridge
et al. (2013) indicated that diversication within Dasyatidae began well before the Oligocene. In their
recent study of Hypanus diversity, Petean et al. (2024) did not discuss the timing of diversication but
recognized three clades within Hypanus. Two of these clades, including the H. americanus and H. say
complexes, have representatives living within the present-day Gulf of Mexico (Hoese & Moore 1998).
Two dasyatid taxa were reported from the Rupelian Ashley Formation of South Carolina by Cicimurri
et al. (2022), including “Taeniurops” cavernosus (Probst, 1877) and “Dasyatis” sp. The low-crowned
morphotype of the former taxon is comparable to the low-crowned teeth from the Catahoula Formation.
However, the high-crowned morphology shown by Cicimurri et al. (2022: g. 7o, u) has more extensive
labial ornamentation and a more vertically oriented cusp compared to the Catahoula Formation high-
crowned morphotype (compare to Fig. 16J, T). With respect to low-crowned Miocene teeth assigned to
T. cavernosus, these have in common with the Ashley Formation “T.” cavernosus specimens a deeper
apical depression on the labial face that is framed basally by a more conspicuous transverse ridge-like
structure (i.e., Cappetta 1970; Villafaña et al. 2020). This morphology is particularly evident on extant
T. grabatus (Georoy Saint-Hilaire, 1817) teeth (see Reinecke et al. 2023) and is unlike that of Hypanus?
heterodontus sp. nov. teeth.
Fig. 18. Hypanus? heterodontus sp. nov. (A–J) and Dasyatidae gen. et sp. indet. (K–T), teeth.
A–E. SC2013.28.475, Hypanus? heterodontus, tooth. A. Occlusal view. B. Labial view. C. Lingual
view. D. Prole view. E. Basal view. F–J. SC2013.28.470, Hypanus? heterodontus, tooth. F. Occlusal
view. G. Labial view. H. Lingual view. I. Prole view. J. Basal view. K–O. SC2013.28.429, Dasyatidae
gen. et sp. indet., tooth. K. Occlusal view. L. Labial view. M. Lingual view. N. Prole view. O. Basal
view. P–T. SC2013.28.430, Dasyatidae gen. et sp. indet., tooth. P. Occlusal view. Q. Labial view.
R. Oro-lingual view. S. Prole view. T. Basal view. Scale bars = 2 mm.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
63
Cicimurri & Knight (2009) reported two dasyatid morphotypes from the Chattian Chandler Bridge
Formation that are similar to “Hypanus” specimens from the Catahoula Formation. Both morphotypes
are slightly larger than the Catahoula specimens, and material identied as Dasyatis cavernosa (Probst,
1877) by Cicimurri & Knight (2009: g. 8a) has a narrower transverse crest and more extensive labial
ornamentation compared to Hypanus? heterodontus sp. nov. A tooth referred to D. rugosa (Probst, 1877)
by Cicimurri & Knight (2009: g. 8c) is also comparable to certain Catahoula Formation specimens,
but the ornamentation on the South Carolina taxon appears to consist of indistinct rugosities rather than
interconnected ridges. Gynandric heterodonty was also documented in the Chandler Bridge sample, as
a male tooth attributed to D. cavernosa (Probst, 1877) by Cicimurri & Knight (2009: g. 8b) is quite
similar to male teeth of Hypanus? heterodontus from the Catahoula Formation (Fig. 17K).
The low-crowned teeth of Hypanus? heterodontus sp. nov. appear to have a more consistently developed
apical labial depression and less organized reticulated ornamentation compared to equivalent teeth from
the Oligo-Miocene of Germany identied as Dasyatis delfortriei Cappetta, 1970 (Reinecke et al. 2005;
Haye et al. 2008). The high-crowned (male) teeth of the latter taxon also have a distinctive reticulated
labial crown ornamentation compared to similarly shaped teeth of the former taxon (see also Reinecke
et al. 2023: text-g. 1). Low-crowned teeth of the Oligocene Dasyatis rugosa from Germany appear to
have a more convex basal portion of the labial face as well as more extensive ornamentation compared
to the Catahoula Formation specimens, and high-crowned teeth of the former are also more extensively
ornamented compared to Hypanus? heterodontus (Haye et al. 2008; Reinecke et al. 2008). Low-
crowned teeth of Dasyatis strangulata (Probst, 1877) from the Oligo-Miocene of Germany (Reinecke
et al. 2008, 2014; also Reinecke & Radwański 2015) lack an apical labial depression, as typically occurs
on the Catahoula Formation low-crowned specimens. Additionally, low-crowned teeth of Dasyatis sp.
from the Thalberg Beds have more strongly developed crown ornamentation compared to the Catahoula
Formation specimens, and the ornamentation on male teeth extends onto the transverse crest of the
former but not on the latter (Reinecke et al. 2014). Low-crowned teeth of T. cavernosus from Miocene
strata appear to have a more concave labial face framed by a conspicuous transverse ridge-like structure,
a morphology quite obvious on extant Taeniurops grabatus (Villafaña et al. 2020; Reinecke et al. 2023).
Dasyatidae gen. et sp. indet.
18K–T
Material examined
UNITED STATES OF AMERICA – Mississippi • 3 isolated teeth; Catahoula Formation; SC2013.28.429
(Fig. 18K–O), SC2013.28.430 (Fig. 18P–T), SC2013.28.479.
Description
The large dasyatid teeth are wider (mesio-distally) than long (labio-lingually). Specimen SC2013.28.429
measures 4 mm wide and 3 mm long, and SC2013.28.430 measures 3 mm and 2.5 mm, respectively,
in these dimensions. In occlusal view, the crown is divided into labial and lingual parts by a sharp
transverse crest (Fig. 18K, P) that does not reach the mesial and distal base of the crown (Fig. 18N, S).
The lingual side of the crown is more expansive, and its margin is strongly convex but may be somewhat
squared. The labial margin is weakly to moderately convex. The labial face of S2013.28.429 is concave
medially but otherwise weakly convex mesio-distally, whereas SC2013.28.430 has a more uniformly
convex labial face. In prole view, the labial crown foot is highly convex, but apically the surface is
relatively at. Both specimens have a broad but low, medially located, and rounded ridge that divides
the lingual face into concave mesial and distal parts (Fig. 18M, R). This ridge intersects with the cusp
apex, which is at on both specimens due to in vivo wear. The worn occlusal surface of both specimens
exhibits an elliptical to D-shaped outline and the internal dentine is visible (Fig. 18K, P). In labial view,
the cusp on SC2013.28.429 is more clearly distinguished (Fig. 18L), and in prole view it appears to
European Journal of Taxonomy 984: 1–131 (2025)
64
be distally curved (Fig. 18N). The crown of SC2013.28.430 is more extensively worn and the nature of
the cusp is unknown. The crown enameloid is smooth, although SC2013.28.430 exhibits two unusual,
indistinct node-like features on the labial face. The crown extends well beyond the root labially and
laterally (Fig. 18R–S). The root of both specimens is ablated, but that on SC2013.28.430 is low and
completely divided into two lobes by a nutritive groove (Fig. 18T). In basal view, a foramen is located
within the groove, and root lobes have a crescent-shaped outline. The basal view also makes evident
how small the root is compared to the size of the crown, that enameloid extends onto the underside of
the crown (especially labially), and the root lobes extend beyond the lingual crown margin (Fig. 18O, T).
Remarks
Specimens SC2013.28.429 and SC2013.28.430 are of large size and have unornamented enameloid,
which clearly distinguishes them from the teeth of Hypanus? heterodontus sp. nov. that also occur in
the Catahoula Formation (see above). Specimen SC2013.28.429 is highly ablated but is comparable
to, although smaller than, SC2013.28.430. Cicimurri & Knight (2009) reported a similarly large and
smooth-crowned dasyatoid tooth morphology from the Chattian Chandler Bridge Formation of South
Carolina, which Reinecke et al. (2014) proposed as a possible representative of Taeniurops. However,
teeth of extant Taeniurops grabatus exhibit a conspicuous labial depression not observed on the U.S.
Oligocene specimens. Additionally, teeth of extant Dasyatis pastinaca (Linnaeus, 1758) and Neotrygon
orientalis Last, White & Séret, 2016 have smooth crowns and supercially similar tooth shapes, further
complicating our ability to accurately identify the Catahoula Formation specimens (see Reinecke et al.
2023). Specimens SC2013.28.429 and SC2013.28.430 are reminiscent of Middle Miocene specimens
from France that Cappetta named Dasyatis serralheiroi (Cappetta 1970: 92–95, pl. 20 gs 1–16.
However, we hesitate to identify the material beyond the family level due to the limited comparative
material available to us.
Family Myliobatidae Bonaparte, 1840a
Genus Myliobatis Cuvier, 1816
Type species
Raja aquila Linnaeus, 1758, Extant.
“Myliobatis” sp.
Fig. 19A–L
Material examined
UNITED STATES OF AMERICA – Mississippi • 170 isolated teeth; Catahoula Formation; MMNS
VP-12061 (21 teeth), MMNS VP-12062 (Fig. 19A–C), SC2013.28.363 (Fig. 19D–F), SC2013.28.364
(Fig. 19G–I), SC2013.28.365 to 28.370, SC2013.28.371 (3 teeth), SC2013.28.372 (2 teeth),
SC2013.28.373 (3 teeth), SC2013.28.374 (2 teeth), SC2013.28.375, SC2013.28.376, SC2013.28.377
(13 teeth), SC2013.28.378, SC2013.28.379, SC2013.28.380 (18 teeth), SC2013.28.381 (40 teeth),
SC2013.28.382 (54 teeth) • 1 dentition; Catahoula Formation; MMNS VP-12063 (Fig. 19J–L).
Description
This sample contains teeth that are much wider (mesio-distally) than long (labio-lingually). In occlusal
view, the crown is six-sided, with somewhat rounded lateral angles that are located closer to the labial
margin, and the overall shape ranges from arcuate (i.e., the labial margin concave and lingual margin
convex) to straight (Fig. 19A, D, G). Other teeth have a four-sided, squared appearance in occlusal
view due to the signicantly reduced area of the labial and lingual crown faces. Width and length
dimensions of these latter teeth are roughly equal. In prole view, the labial and lingual faces of all teeth
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
65
Fig. 19. “Myliobatis” sp. (A–L) and “Aetomylaeus” sp. (M–DD), teeth. A–C. MMNS VP-12062,
“Myliobatis” sp., upper symphyseal tooth. A. Occlusal view. B. Labial view. C. Basal view.
D–F. SC2013.28.363, “Myliobatis” sp., lower symphyseal tooth. D. Occlusal view. E. Labial view.
F. Basal view. G–I. SC2013.28.364, “Myliobatis” sp., upper symphyseal tooth. G. Occlusal view.
H. Labial view. I. Basal view. J–L. MMNS VP-12063, “Myliobatis” sp., upper tooth plate. J. Occlusal
view. K. Basal view. L. Left prole view. M–N. MMNS VP-12064.1, “Aetomylaeus” sp., lower tooth
plate. M. Occlusal view. N. Basal view. O–Q. MMNS VP-12065, “Aetomylaeus” sp., fragmentary upper
tooth plate. O. Occlusal view. P. Labial view. Q. Basal view. R–V. MMNS VP-12066, “Aetomylaeus”
sp., lateral tooth. R. Occlusal view. S. Distal view. T. Labial view. U. Mesial view. V. Basal view.
W–Z. SC2013.28.383, “Aetomylaeus” sp., partial symphyseal tooth. W. Occlusal view. X. Lingual
view. Y. Labial view. Z. Basal view. AA–DD. SC2013.28.384, “Aetomylaeus” sp., partial symphyseal
tooth. AA. Occlusal view. BB. Lingual view. CC. Labial view. DD. Basal view. Scale bars: A–L,
O–DD = 1 cm; M–N = 2 cm.
European Journal of Taxonomy 984: 1–131 (2025)
66
are lingually inclined, although one large specimen demonstrates a very thick crown with a concave
labial (and convex lingual) crown foot transitioning to a more vertical face. The labial face of relatively
unworn crowns bears a reticulated network of ridges near the crown foot, which transitions to irregular
vertical ridges towards the apex (Fig. 19B). The lingual face is tuberculated basally but otherwise
exhibits irregular vertical ridges towards the apex. The labial crown foot may be formed into a thin
ridge-like projection that overhangs the root. The lingual crown foot bears a thin, shelf-like transverse
ridge that further distinguishes the crown from the root. The crown also overhangs the root on the mesial
and distal sides, but lingually the root extends a short distance beyond the transverse ridge. The root is
low and may have a straight or convex basal attachment surface, depending on tooth position. The labial
face of the root is weakly lingually inclined. In basal view, the root is dierentiated into numerous thin,
closely spaced, parallel lamellae by nutritive grooves (Fig. 19C, F, I).
Remarks
Monognathic, dignathic, and ontogenetic heterodonty are evident in our sample. Monognathic heterodonty
is expressed as a drastic transition (disjunct heterodonty) from very wide teeth of symphyseal les to
more symmetrical, roughly diamond-shaped teeth in lateral les, the exact number of which in the
dentition of this ray is unknown. Upper symphyseal teeth can be identied by their convex occlusal
outline and straight basal attachment surface (Fig. 19B, H). In contrast, lower symphyseal teeth have
a straight occlusal outline and convex basal attachment surface (Fig. 19E). We could not identify a
feature among the fossil specimens that would allow the upper lateral teeth to be dierentiated from
those in the lower les. Ontogenetic variation is apparent based on the morphological criteria noted for
“Rhinoptera” sp. (see below). MMNS VP-12063 (Fig. 19J–L) is an ablated upper dentition consisting
of fused symphyseal and lateral teeth. The specimen shows that the upper dentition was convex both
labio-lingually and mesio-distally.
The teeth we identify as “Myliobatis” sp. dier from those of “Rhinoptera” sp. by their basally reticulated
to apically ridged labial crown faces, basally tuberculated to apically ridged lingual crown faces, lateral
angles that are located closer to the labial crown margin, thin and shelf-like lingual transverse ridge
at the crown foot, and root lamellae that extend beyond the lingual crown foot. Although these teeth
exhibit morphological similarities to those of extant Myliobatis, molecular divergence estimates indicate
that most extant myliobatid genera diverged from one another at sometime during the Early-to-Middle
Miocene (Villalobos-Segura & Underwood 2020). This, in turn, indicates that the early Chattian teeth
in our sample likely belong to a genus that is ancestral to extant Myliobatis. Therefore, herein we refer
these teeth to “Myliobatis” with the understanding that future studies may assign this morphology to a
new stem genus within the Myliobatis lineage.
Genus Aetomylaeus Garman, 1908
Type species
Myliobatus maculatus Gray 1834, Extant.
“Aetomylaeus” sp.
Fig. 19M–DD
Material examined
UNITED STATES OF AMERICA – Mississippi • 49 isolated teeth; Catahoula Formation; MMNS
VP-12064 (3 teeth), MMNS VP-12065 (4 teeth), MMNS VP-12066 (Fig. 19R–V), SC2013.28.383
(Fig. 19W–Z), SC2013.28.384 (Fig. 19AA–DD), SC2013.28.385 to 28.388, SC2013.28.389 (8 teeth),
SC2013.28.390, SC2013.28.391 (3 teeth), SC2013.28.392 (3 teeth), SC2013.28.393 (20 teeth) • 2
dentitions; Catahoula Formation; MMNS VP-12064.1 (Fig.19M–N), MMNS VP-12065.1 (Fig. 19O–Q).
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
67
Description
Teeth in the sample are generally mesio-distally much wider than long (labio-lingually). In occlusal
view, the six-sided crown exhibits obtuse lateral angles that are located closer to the lingual margin, and
the occlusal outline ranges from straight to slightly arcuate. Other teeth have a four-sided appearance
in occlusal view due to the diminutive area of the labial and lingual faces. These teeth are much longer
(labio-lingually) than wide (mesio-distally) and have an elongated diamond-shaped outline (Fig. 19R).
In prole view, the labial and lingual faces of all teeth are lingually inclined (Fig. 19U). Well-preserved
teeth show that the labial face bears a reticulated network of ridges that may transition to vertical ridges
near the apex (Fig. 19Y, CC). The lingual face is largely tuberculated but bears irregular vertical ridges
near the apex (Fig. 19X, BB). The labial crown foot overhangs the root, and the basal surface exhibits
a longitudinal furrow. A very thin and sharp transverse ridge occurring at the lingual crown foot is
inconspicuous. The crown also overhangs the root on the mesial and distal sides, but lingually the root
extends well beyond the crown foot. The root is low and may have a straight or convex basal attachment
surface, depending on tooth position. In basal view, the root is dierentiated into numerous thin, closely
spaced, parallel lamellae by nutritive grooves (Fig. 19Z, DD).
Remarks
Monognathic, dignathic, and ontogenetic heterodonty in our sample was determined based on the
morphological criteria described above for “Myliobatis” sp. Specimens MMNS VP-12064.1 (Fig. 19M–
N) and 12065.1 (Fig. 19O–Q) show that the lower dentition was at labio-lingually and mesio-distally.
Symphyseal teeth of “Aetomylaeus” sp. can be separated from “Myliobatis” sp. and “Rhinoptera” sp.
(see below) by the more uniformly reticulated ornamentation on the labial and lingual faces, lateral
angles that are located closer to the lingual crown margin, the very thin and inconspicuous transverse
ridge at the lingual crown foot, and a root that extends well beyond the lingual crown foot. Lateral
teeth of “Aetomylaeus” sp. (Fig. 19R–V) also dier from those of “Myliobatis” sp. by their being labio-
lingually longer than mesio-distally wide (whereas they are roughly equal in these dimensions in the
latter taxon). Except for the ultimate lateral le, lateral teeth of “Rhinoptera” sp. are all six-sided. Those
from medial lateral positions are roughly hexagonal, whereas the ultimate lateral tooth has a pentagonal
occlusal outline. We note that specimens are often worn through in vivo use down to the crown foot.
However, even highly worn specimens can be accurately identied based on the nature of the lingual
transverse ridge and lingual elongation of the root.
It is dicult to determine the Oligocene geographic and stratigraphic distribution of “Aetomylaeus”
because: 1) Oligocene sh faunas in the USA are relatively uncommon and 2) Paleogene Myliobatidae
teeth generally appear to be (mis)identied as Myliobatis or Rhinoptera simply based on overall shape
(see discussion in Ebersole et al. 2019). Cicimurri & Knight (2009) reported a tooth from the Chattian
Chandler Bridge Formation of South Carolina (as Myliobatidae gen. indet.) that compares favorably
to the Catahoula Formation “Aetomylaeus” sp. Ebersole et al. (2021) recently reported similar teeth
derived from the Rupelian (NP23) Byram Formation of Alabama that they identied as “Aetomylaeus”
sp. As with “Myliobatis” sp., the teeth in our sample likely represent an undescribed Oligocene member
of the extant Aetomylaeus lineage and are therefore referred to herein as “Aetomylaeus” sp.
Family Rhinopteridae? Jordan & Evermann, 1896
Genus Rhinoptera Cuvier, 1829
Type species
Myliobatis marginata Georoy Saint-Hilaire, 1817, Extant.
European Journal of Taxonomy 984: 1–131 (2025)
68
“Rhinoptera” sp.
Fig. 20
Material examined
UNITED STATES OF AMERICA – Mississippi • 110 isolated teeth; Catahoula Formation; MMNS VP-
12059 (Fig. 20E–H), MMNS VP-12060 (Fig. 20I–L), SC2013.28.336 to 28.343, SC2013.28.344 (Fig.
20A–D), SC2013.28.345, SC2013.28.346, SC2013.28.347 (Fig. 20M–Q), SC2013.28.348 to 28.353,
SC2013.28.354 (4 teeth), SC2013.28.355 (3 teeth), SC2013.28.356 (4 teeth), SC2013.28.357 (10 teeth),
SC2013.28.358 (11 teeth), SC2013.28.359 (4 teeth), SC2013.28.360 (4 teeth), SC2013.28.361
(12 teeth), SC2013.28.362 (38 teeth).
Description
Teeth vary in width, and relatively unworn specimens exhibit a thick crown. In occlusal view, the crown
is six-sided with sharp and centrally located lateral angles that are acute to roughly 90º. The overall
shape is variable (straight, sinuous, or weakly convex). In prole view, the labial and lingual faces are
vertical to slightly lingually inclined. The labial and lingual faces are generally heavily corrugated with
vertical ridges, which are overprinted with ner vertical ridges (Fig. 20J–K). The ornamentation on the
lingual face is usually less developed than on the labial face, and ornament appears to become obsolete
apically. Some specimens show that lingual ornamentation can consist of short basal vertical ridges that
transition apically to beaded ridges. The labial crown face overhangs the root, and the basal surface of
the crown base bears a shallow transverse furrow. The lingual crown foot is marked by a very thick and
rounded, shelf-like transverse ridge. The root is low with nearly vertical labial and lingual faces. In basal
view, the root is subdivided into numerous thin, parallel lamellae by nutritive grooves. The lamellae
are perpendicular or oblique to the tooth width (Fig. 20H). The lingual face of the root does not extend
beyond the crown foot.
Lateral teeth vary in mesio-distal width but are generally six-sided and similar to the symphyseal teeth in
all other aspects. The ultimate lateral tooth, the last tooth at the margin of the dentition, has a ve-sided
occlusal outline. The mesial side has a sharply angular margin, whereas the distal side is a straight edge
that parallels the length of the dentition. The crown of lateral teeth is higher on the mesial side than on
the distal side (Fig. 20C, J). Root lamellae are oblique to crown width (Fig. 20D, L).
Remarks
Monognathic and ontogenetic heterodonty are evident in our sample. Monognathic heterodonty is
expressed as a transition from a very wide symphyseal le to lateral les that become progressively less
wide (gradient heterodonty) towards the commissure. From the symphysis (Fig. 20E–H), the mesio-
distal tooth width in succeeding lateral les progressively decreases from roughly three times as wide
as long (Fig. 20I–L) to two times as wide as long (Fig. 20M–Q), to symmetrically hexagonal. The exact
number of les of each morphology is unknown, as our sample does not include complete tooth plates.
The margin of the dentition was formed of teeth with a pentagonal outline, where the mesial margin is
angular and the distal margin straight. Dignathic heterodonty is dicult to discern based on the sample,
but transversely convex specimens (Fig. 20G) may have comprised the upper dentition. Overall, these
teeth are arched, but there is a medial region where the crown is worn at. In contrast, relatively at teeth
with roughly uniformly worn crowns were likely part of the lower dentition. Ontogenetic heterodonty
is identied based on the variation in tooth size within the sample available to us, which presumably
reects juvenile (i.e., smaller teeth) and adult specimens.
Cicimurri et al. (2022) reported “Rhinoptera” sp. teeth from the Rupelian Ashley Formation, and
Cicimurri & Knight (2009) identied Rhinoptera cf. studeri (Agassiz, 1843) from the Chattian Chandler
Bridge Formation of South Carolina. These identications were based on very limited and fragmentary
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
69
specimens, and it is dicult to make accurate comparisons between that material and the Catahoula
Formation sample. Müller (1999) identied R. a. brasiliensis Müller, 1836 and R. a. bonasus Mitchill,
1815 in his sample of teeth from the Oligo-Miocene Belgrade Formation of North Carolina. That material
does appear to be similar to the Catahoula Formation sample in terms of gross morphology and crown
ornamentation on the vertical faces. However, it is unlikely that the fossil specimens represent extant
taxa, particularly considering that the genus Rhinoptera apparently did not diverge from Myliobatidae
until the Miocene (Naylor et al. 2012; Villalobos-Segura & Underwood 2020). Additionally, the
variation we observed in the Catahoula Formation sample, which is also reected in the sample reported
by Müller (1999), is attributed herein to intraspecic variation (heterodonty) rather than the presence of
multiple species. This interpretation is supported by the work of Hovestadt & Hovestadt-Euler (2013),
who documented variation within dentitions of extant myliobatiform species. We follow other authors in
placing the generic name Rhinoptera in quotation marks to acknowledge the dental similarities between
the Oligocene taxon and extant Rhinoptera, and to address the temporal separation of the occurrences
(Ebersole et al. 2019; Cicimurri et al. 2022).
We place the Catahoula Formation taxon within Rhinopteridae following the conclusions of phylogenetic
studies for extant Rhinoptera (i.e., Palacios-Barreto et al. 2023) and the very close similarity of
the fossil teeth to those of extant members of this genus. However, this assignment is tentative if
Rhinoptera/Rhinopteridae diverged from Myliobatidae during the Miocene. Ebersole et al. (2019)
reported “Rhinoptera” sp. teeth from Ypresian, Lutetian, and Bartonian strata of Alabama that were all
comparable to each other in terms of overall shape and crown ornamentation. Those authors therefore
Fig. 20. “Rhinoptera” sp., teeth. A–D. SC2013.28.344, proximal lateral tooth. A. Occlusal view.
B. Lingual view. C. Labial view. D. Basal view. E–H. MMNS VP-12059, upper symphyseal tooth.
E. Occlusal view. F. Lingual view. G. Labial view. H. Basal view. I–L. MMNS VP-12060, proximal
lateral tooth. I. Occlusal view. J. Lingual view. K. Labial view. L. Basal view. M–Q. SC2013.28.347,
distal lateral tooth. M. Occlusal view. N. Labial view. O. Basal view. P. Lingual view. Q. Prole view.
Scale bars = 1 cm.
European Journal of Taxonomy 984: 1–131 (2025)
70
could not determine, based on tooth shape alone, whether one or more species were represented in
their temporally wide-ranging sample. The Catahoula Formation “Rhinoptera” sp. specimens exhibit
features comparable to those Eocene examples (i.e., vertical ridges sometimes transitioning to apical
beaded ridges, wide lingual transverse ridge), and we therefore refrain from making a more specic
determination without the aid of more complete (i.e., skeletal) material.
Family Mobulidae Gill, 1893?
Genus Plinthicus Cope, 1869
Type species
Plinthicus stenodon Cope, 1869, Oligocene (Rupelian), New Jersey, USA.
Plinthicus sp.
Fig. 21A–D
Material examined
UNITED STATES OF AMERICA – Mississippi • 1 isolated tooth; Catahoula Formation;
SC2013.28.522.
Description
The tooth is wider than long (4.5 mm and 2.5 mm in these dimensions), and the crown measures 2 mm
in height. In occlusal view, the crown has a roughly oval outline, and the occlusal surface is concave.
The labial margin is thickened and forms a conspicuous rim around the depressed oral surface, but
the lingual margin is thin and developed into a thin, lingually directed, shelf-like projection. In prole
view, the labial and lingual faces are highly inclined (Fig. 21D), and the surfaces bear numerous robust,
irregular vertical ridges. The labial crown foot is formed into a sharp projection that overhangs the root
(Fig. 21C), whereas there is a thick and rounded transverse ridge at the lingual crown foot (Fig. 21A).
The root is not well preserved but appears to have been smaller in area than the crown.
Remarks
Specimen SC2013.28.522 is easily distinguished from the supercially similar myliobatiform teeth
described above by its concave occlusal surface, thinner prole, and coarse vertical ridges on the labial
and lingual faces. Plinthicus has been reported from Oligocene strata of South Carolina (Cicimurri &
Knight 2009; Cicimurri et al. 2022), but it is dicult to accurately compare the ablated Catahoula
Formation specimen to the South Carolina material. However, Cicimurri et al. (2022) indicated that
the Ashley Formation specimens (ca 28.5 Ma) diered from Mio-Pliocene P. stenodon Cope, 1869
and could represent a new species. The Catahoula Formation tooth clearly diers from P. kruibekensis
Bor, 1990 from the Rupelian Boom Clay Formation of Belgium by its inclined labial and lingual faces
that bear coarse but few vertical ridges. In contrast, the Belgian taxon has a convex labial and concave
lingual face that bears ner and more numerous vertical ridges. Although recent taxonomic rankings
place extant lter-feeding “devil rays” within Mobulidae (i.e., Notabartolo di Sciara 2020), it may not
be correct to include all extinct mobulid-like taxa within this family. Villalobos-Segura & Underwood
(2020) presented molecular divergence times for various batoid taxa that indicate that the clade
containing Mobulidae did not diverge from its common ancestor until the Early Miocene. Therefore,
it does not appear to be prudent to refer Paleogene mobulid-like teeth of presumed planktivorous rays
to Mobulidae. However, for the purposes of this report we tentatively follow convention for familial
assignment of this genus.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
71
Genus Paramobula Pfeil, 1981
Type species
Manta fragilis Cappetta, 1970, Middle Miocene, southern France.
Paramobula fragilis (Cappetta, 1970)
Fig. 21E–N
Mantra fragilis Cappetta, 1970: 112–113.
Material examined
UNITED STATES OF AMERICA – Mississippi • 2 isolated teeth; Catahoula Formation; MMNS VP-
8429 (Fig. 21E–I), MMNS VP-11678 (Fig. 21J–N).
Description
The crown is wider than long and labio-lingually thin. MMNS VP-8429 measures 4.2 mm in mesio-distal
width and 2.2 mm in total apico-basal height, whereas MMNS VP-11678 is 3.5 mm and 3 mm in these
dimensions. The labial and lingual faces are lingually inclined and heavily ornamented with longitudinal
ridges. These ridges may be wide and widely separated, or thin and closely spaced, or some combination
of both (compare Fig. 21E to J). The ornamentation on the lingual face (Fig. 21G, L) is somewhat less
extensive than that on the labial face. The labial crown foot of MMNS VP-11687 is somewhat ridge-like
and the lingual crown foot is formed into a shelf-like projection. The crown base of MMNS VP-8429 is
Fig. 21. Plinthicus sp. (A–D) and Paramobula fragilis (Cappetta, 1970) (E–N), teeth.
A–D. SC2013.28.522, Plinthicus sp., lateral tooth. A. Lingual view. B. Basal view. C. Labial view.
D. Prole view. E–I. MMNS VP-8429, Paramobula fragilis, tooth. E. Labial view. F. Occlusal view.
G. Lingual view. H. Basal view. I. Distal view. J–N. MMNS VP-11678, P. fragilis, tooth. J. Labial view.
K. Occlusal view. L. Lingual view. M. Basal view. N. Distal view. Scale bars = 3 mm.
European Journal of Taxonomy 984: 1–131 (2025)
72
formed into a robust cingulum that extends around the entire perimeter. The complex occlusal surface is
at to weakly depressed and has very irregular labial and lingual margins (Fig. 21F, K). Additionally, in
prole view, the occlusal surface is lingually inclined and rather straight (Fig. 21I). The root is high but
labio-lingually thin, and it is located close to the lingual crown margin (Fig. 21N). The basal surface is
subdivided into four or ve thin lamellae by wide and shallow nutritive grooves (Fig. 21H, M).
Remarks
These two teeth clearly dier from that of Plinthicus sp. (see above) by the much coarser labial and
lingual ornamentation and by the at occlusal surface that has a highly irregular outline. In contrast, the
Plinthicus sp. tooth in our sample (SC2013.28.522) has a distinctively concave occlusal surface.
Specimens MMNS VP-8429 and MMNS VP-11678 are comparable to teeth that Cicimurri & Knight
(2009) identied as Paramobula fragilis (Cappetta, 1970) from the Chandler Bridge Formation of South
Carolina. Comparison of the Catahoula Formation teeth to a small sample from the Chandler Bridge
Formation (SC2005.2) indicates that the material is conspecic. The taxon Manta fragilis was named by
Cappetta (1970) based on teeth from the Middle Miocene (Langhian) of France (Cappetta 1970: pl. 28
g. 10) that have a high, labio-lingually narrow crown that bears signicant vertical ridges on the labial
and lingual faces. Pfeil (1981) later erected the name Paramobula for this morphology, but Cappetta
& Stringer (2002) and Cappetta (2012) synonymized the genus with Mobula. However, the fragilis
morphology is signicantly dierent from teeth of extant Mobula species (see Notabartolo di Sciara
1987) and fossil species like M. loupianensis Cappetta, 1970. We therefore resurrect Paramobula Pfeil,
1981 to accommodate the more Plinthicus-like nature of the fragilis morphotype.
Batomorphi fam., gen. et sp. indet.
Fig. 22A–L
Material examined
UNITED STATES OF AMERICA – Mississippi • 326 poorly preserved isolated teeth; Catahoula
Formation; SC2013.28.394 to 28.398, SC2013.28.399 (2 specimens), SC2013.28.400 (49 specimens),
SC2013.28.401 (19 specimens), SC2013.28.402 (16 specimens), SC2013.28.403 (17 specimens),
SC2013.28.404 (218 specimens) • 9 dermal thorns; Catahoula Formation; MMNS VP-6650.1
(Fig. 22G–I), MMNS VP-6650.2 (Fig. 22D–F), MMNS VP-8066.1 (Fig. 22J–L), MMNS VP-8066.2,
SC2013.28.405, SC2013.28.518, SC2013.28.520, SC2013.28.521, SC2013.28.528 • 43 caudal
spines; Catahoula Formation; MMNS VP-7035 (13 specimens), MMNS VP-7035.1 (Fig. 22A–C),
SC2013.28.480, SC2013.28.481, SC2013.28.482, SC2013.28.483 (16 specimens), SC2013.28.484,
SC2013.28.485 (9 specimens).
Description
Several thorn-like denticles measuring up to 3.5 mm in antero-postero length and 2.5 mm in medio-
lateral width consist of a rather small crown atop a taller and wider base. The crown is small, conical,
and covered with smooth enameloid. Some of these denticles (i.e., Fig. 22D–F) have a high conical base
that bears numerous widely spaced radiating furrows. Although the furrows reach the crown foot, they
do not extend to the base of the crown. Other similar denticles (Fig. 22G–I) are laterally compressed
with broad and nearly vertical sides that bear ne vertical striations. Both types of denticles have a
circular to sub-rectangular basal outline (Fig. 22E, H), and the basal surface is weakly convex (Fig. 22D,
G). An additional denticle morphotype is comprised of a triangular, highly distally inclined crown and
very thin base (Fig. 22J–L). Smooth enameloid is limited to the dorsal surface of the crown. The base is
ared outward from the crown, has a roughly triangular outline, and the basal surface is weakly concave.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
73
The caudal spines in our sample are elongated, distally tapering, and dorso-ventrally attened
(Fig. 22A–C). The dorsal surface is covered by enameloid except for the distal end, where the element
was embedded in soft tissue. The proximal end is also wide and spatulate, whereas the distal tip is
Fig. 22. Elasmobranchii indet., remains: Myliobatiformes gen. et sp. indet. (A–C), Batomorphi fam.,
gen. et sp. indet. (D–L), and Galeomorphii fam., gen. et sp. indet. (M–U). A–C. MMNS VP-7035.1,
Myliobatiformes gen. et sp. indet., caudal spine. A. Dorsal view. B. Ventral view. C. Right prole view.
D–F. MMNS VP-6650.2, Batomorphi fam., gen. et sp. indet., dermal denticle. D. Prole view. E. Apical
view. F. Basal view. G–I. MMNS VP-6650.1, Batomorphi fam., gen. et sp. indet., dermal denticle.
G. Prole view. H. Apical view. I. Basal view. J–L. MMNS VP-8066.1, Batomorphi fam., gen. et sp. indet.,
dermal denticle. J. Prole view. K. Apical view. L. Basal view. M–O. MMNS VP-7750, Galeomorphii
fam., gen. et sp. indet., placoid scale. M. Prole view. N. Apical view. O. Basal view. P–R. MMNS
VP-7753, Galeomorphii fam., gen. et sp. indet., symphyseal tooth. P. Distal view. Q. Lingual view.
R. Labial view. S–U. MMNS VP-8741.1, Galeomorphii fam., gen. et sp. indet., symphyseal tooth.
S. Distal view. T. Lingual view. U. Labial view. Scale bars: A–C = 2 cm; D–L = 5 mm; M–U = 1 mm.
European Journal of Taxonomy 984: 1–131 (2025)
74
sharply pointed. The ventral surface lacks enameloid and has a single robust, rounded medial ridge that
parallels the spine length (Fig. 22B). The right and left lateral surfaces bear a single row of denticles.
The closely spaced denticles are enameloid-covered, sharply angled proximally, and sharply pointed
(Fig. 22A). Denticle size is consistent except for the distal tip, where they quickly decrease in size.
Remarks
The 326 highly worn symphyseal and lateral teeth represent elements from durophagous ray dentitions.
These include complete and broken specimens with tooth crowns that have been worn through in
vivo use down to, and beyond, the lingual transverse ridge. Many specimens have also been modied
through post mortem transport, as they are polished and have rounded edges and corners. Thus, their
taxonomically signicant features, like crown ornamentation, shape of the lingual transverse ridge, and
nature of the root lobes, are not preserved. We could therefore not determine whether the specimens
represent “Rhinoptera” sp., “Myliobatis” sp., or “Aetomylaeus” sp., but they are included here for
completeness and to document the overall abundance of durophagous ray teeth.
One thorn-like denticle morphology (not shown), represented by SC2013.28.405, is comparable to a
denticle from the Chattian Chandler Bridge Formation of South Carolina that Cicimurri & Knight (2009)
assigned to Dasyatidae (see their g. 8e). MMNS VP-8066 (Fig. 22J–L) is reminiscent of dermal thorns
referred to Bathytoshia centroura (Mitchill, 1815) by Purdy et al. (2001). Other denticles like those
shown in Fig. 22D–F and G–I (also including SC2013.28.520, SC2013.28.521 and SC2013.28.528) are
similar to each other and are believed to represent the same taxon. It is possible these represent one of
the rhinopristiform shes we identied by teeth (i.e., Rhynchobatus).
Although there is slight variation in the gross morphology of the caudal spines, the shape of the lateral
denticles is consistent, and the specimens could represent the same taxon. Unfortunately, we cannot
say with certainty to which species they belong, but it is likely they represent one (or more) of the taxa
within Dasyatidae or Myliobatidae we identied by their teeth.
Euselachii fam., gen. et sp. indet.
Fig. 9C–D, 22M–U
Material examined
UNITED STATES OF AMERICA – Mississippi • 10 placoid scales; Catahoula Formation; MMNS VP-
7750 (Fig. 22M–O), SC2013.28.330, SC2013.28.331 (2 specimens), SC2013.28.332, SC2013.28.333
(2 specimens), SC2013.28.334 (2 specimens), SC2013.28.529, SC2013.28.530 • 10 teeth; Catahoula
Formation; MMNS VP-7753 (Fig. 22P–R), MMNS VP-8736, MMNS VP-8741.1 (Fig. 5–U), MMNS
VP-8741.2, SC2013.28.115 (Fig. 9C–D), SC2013.28.264 (2 specimens), SC2013.28.265 (2 specimens),
SC2013.28.268.
Description
Specimens assigned only to Euselachii indet. include teeth and placoid scales. Several small teeth consist
of a simple triangular main cusp and bilobate root (Fig. 22P–U). The crown has smooth to weakly
serrated cutting edges that may not extend to the apex or crown foot. The labial face is nearly at, but
the lingual face is convex, and both faces have smooth enameloid. The root is robust for the size of the
tooth, and very short root lobes are separated by a well-developed lingual nutritive groove.
Placoid scales consist of an enameloid-covered crown and dentine base (Fig. 22M–O). The crown on
each specimen is apico-basally attened, and the apical surface may be weakly convex or at. The apical
outline is oval or rhomboidal. Several specimens have smooth enameloid, but others exhibit a series of
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
75
parallel ridges along the anterior margin (Fig. 22N). These ridges do not extend to the posterior margin.
The base has a somewhat triangular outline in prole, and the basal surface is at.
Remarks
Teeth like those shown in Fig. 22P and S probably belong to a member of Carcharhiniformes, as they are
similar to the symphyseal and parasymphyseal teeth that occur in the jaws of extant Carcharhinus spp.
that we examined. It is possible that specimens with serrated cutting edges are from the upper dentition,
whereas those with smooth cutting edges are from the lower dentition. Several other shark teeth are
too broken or abraded to be condently identied beyond Euselachii. For example, SC2013.28.115
(Fig. 9C–D) is an ablated posterior tooth that bears similarity to the teeth of Galeorhinus (i.e.,
Fig. 9A–B), Physogaleus (i.e., Fig. 7EE–JJ), and Rhizoprionodon (i.e., Fig. 8A–D). The labial crown
foot appears to be thickened as on Galeorhinus teeth, but this may be an artifact of preservation, as
the root is abraded. Additionally, the distal heel is not as clearly separated from the cusp as it is in
Galeorhinus (Fig. 9A; also see Herman et al. 2003). The short and somewhat pointed distal heel is
reminiscent of Physogaleus (Reinecke et al. 2005; Haye et al. 2008) and even Rhizoprionodon (see
Ebersole et al. 2023).
Isolated scales are rare in the elasmobranch component of the Catahoula Formation compared to isolated
teeth. This phenomenon could be related to a collecting bias, but it may be an artifact of winnowing
(removal of very small items through current action). At least two scale morphotypes are represented,
including those with anterior ridges and those that are smooth. We cannot condently assign these
specimens to any particular elasmobranch genus that we identied by its teeth, nor can we determine
whether more than one taxon is represented. However, specimens SC2013.28.334 and MMNS VP-7750
are similar to scales that Dillon et al. (2017) identied as ridged abrasion strength morphotypes (i.e.,
with a protective function), potentially of Ginglymostomatidae.
We include here for completeness nine isolated calcied cartilage tesserae (SC2013.28.335). These have
a columnar appearance when viewed perpendicular to their length, and the surface is roughened. The
outline is six-sided. We cannot determine what skeletal element (probably cranial) nor the species the
tesserae represent.
Class Osteichthyes Huxley, 1880
Subclass Actinopterygii (sensu Goodrich 1930)
Unranked Neopterygii Regan, 1923
Infraclass Holostei Müller, 1845
Division Ginglymodi Cope, 1871
Order Lepisosteiformes Hay, 1929
Family Lepisosteidae Cuvier, 1825
Lepisosteidae gen. et sp. indet.
Fig. 23A–H
Material examined
UNITED STATES OF AMERICA – Mississippi • 109 isolated teeth; Catahoula Formation; MMNS VP-
7685 (7 teeth), SC2013.28.627 to 28.629, SC2013.28.630 (Fig. 23G–H), SC2013.28.631, SC2013.28.632,
SC2013.28.633 (9 teeth), SC2013.28.634 (25 teeth), SC2013.28.635 (12 teeth), SC2013.28.636
(15 teeth), SC2013.28.637 (12 teeth), SC2013.28.638 (19 teeth), SC2013.28.639 to 28.642 • 64 isolated
scales; Catahoula Formation; SC2013.28.609 to 28.617, SC2013.28.618 (Fig. 23A–C), SC2013.28.619
(Fig. 23D–F), SC2013.28.620 to 28.622, SC2013.28.623 (2 specimens), SC2013.28.624 (2 specimens),
SC2013.28.625 (4 specimens), SC2013.28.626 (42 specimens).
European Journal of Taxonomy 984: 1–131 (2025)
76
Description
Numerous isolated teeth are included in our Lepisosteidae sample. These teeth vary in size and overall
height, but all consist of a cylindrical base and enameloid crown (Fig. 23G). In anterior/posterior view,
teeth are straight to slightly lingually curved. The basal portion of the tooth is striated, and the basal
outline is circular with a deep pulp cavity (Fig. 23H). The crown is formed of translucent enameloid
having smooth exterior surfaces. The crown shape of large teeth varies from short and conical to slightly
antero-posteriorly compressed, and those with conical crowns lack cutting edges, whereas compressed
specimens are bicarinate with smooth labio-lingually oriented cutting edges. Small specimens exhibit a
taller, needle-like crown that is conspicuously antero-posteriorly compressed. The crowns of these teeth
exhibit sharp and elongated anterior and posterior cutting edges that do not reach the tooth base.
Two scale morphologies have been identied, both of which are generally rhomboidal in outline but may
also be somewhat teardrop-shaped. The external surface may or may not have a thick ganoine covering.
Those with ganoine may have a smooth texture (Fig. 23A), but specimens with deeply pitted ganoine or
ganoine with highly irregular margins occur (Fig. 23F). The inner surface is smooth (Fig. 23C–D) and
often convex (Fig. 23B, E). A posterior projection from the main body of the scale varies from short to
very elongated. Some specimens exhibit concentric growth lines on the external surface.
Remarks
Of the teeth in our sample, large specimens are comparable to those occurring in furrows along the
maxillae and dentaries of extant Lepisosteus osseus (Linnaeus, 1758) specimens that we examined
(MSC 42585, MSC 49487). The small, more needle-like specimens in our sample are similar to teeth
we observed along the labial jaw margins of those L. osseus specimens. The largest scales in our sample
(i.e., SC2013.28.619) have pitted ganoine or ganoine with irregular outlines and are reminiscent of
scales referred to Atractosteus.
Although Grande (2010) identied four Paleogene gar taxa, he indicated that isolated teeth and scales
lacked taxonomically signicant features allowing for identication beyond the family level. In lieu of
cranial material, we follow Ebersole et al. (2019) and refrain from assigning the Catahoula Formation
gar material to any particular genus. Additionally, we cannot be certain whether dierences in scale
morphology within our sample represent inter- or intraspecic variation (among species versus along
the body of an individual sh). Gar fossils have been documented from Eocene strata within the Gulf
Coastal Plain (i.e., Breard & Stringer 1999; Westgate 2001; Ebersole et al. 2019), but none have been
previously reported from the Oligocene.
Division Teleosteomorpha Arratia et al., 2004
Subdivision Teleostei Müller, 1845
Supercohort Teleocephala de Pinna, 1996
Cohort Elopomorpha Greenwood et al., 1966
Order Albuliformes Greenwood et al., 1966
Family Albulidae Bleeker, 1859
Albulidae gen. et sp. indet.
Fig. 23I–S
Material examined
UNITED STATES OF AMERICA – Mississippi • 6 isolated pharyngeal bones; Catahoula Formation;
MMNS VP-6578 (Fig. 23I–K), MMNS VP-6967 (3 specimens), SC2013.28.692, SC2013.28.693 •
48 isolated teeth; Catahoula Formation; SC2013.28.594 (Fig. 23L–N), SC2013.28.595 (46 teeth),
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
77
SC2013.28.840 (Fig. 23O–Q) • 9 sagittae; Catahoula Formation; MMNS VP-7454, SC2013.28.802,
SC2013.28.803, SC2013.28.804 (2 specimens), SC2013.28.911 (Fig. 23R–S), GLS otolith comparative
collection (3 specimens).
Description
Our sample includes ablated pharyngeal bones, isolated teeth, and otoliths (sagittae). The pharyngeal
bones are ablated, but each specimen exhibits a very attened and slightly polished oral surface
and more convex, roughened aboral surface. A probable basibranchial (MMNS VP-6578) is antero-
posteriorly elongated but narrow. The oral surface of each specimen includes several scattered teeth
(Fig. 23I), which are only visible in outline because of their in vivo wear down to the level of the bone
surface. Numerous openings within the oral surface are interpreted to represent alveoli for missing teeth.
Enameloid crowns of replacement teeth are visible in prole (Fig. 23J) and aboral views (Fig. 23K).
Fig. 23. Lepisosteidae gen. et sp. indet. (A–H) and Albulidae gen. et sp. indet. (I–S), remains.
A–C. SC2013.28.618, Lepisosteidae gen. et sp. indet., scale. A. Outer view. B. Prole view. C. Inner
view. D–F. SC2013.28.619, Lepisosteidae gen. et sp. indet., scale. D. Outer view. E. Prole view.
F. Inner view. G–H. SC2013.28.630, Lepisosteidae gen. et sp. indet., tooth. G. Prole view. H. Basal
view. I–K. MMNS VP-6578, Albulidae gen. et sp. indet., pharyngeal plate. I. Oral view. J. Prole view.
K. Aboral view. L–N. SC2013.28.594, Albulidae gen. et sp. indet., tooth. L. Occlusal view. M. Prole
view. N. Basal view. O–Q. SC2013.28.840, Albulidae gen. et sp. indet., tooth. O. Occlusal view.
P. Prole view. Q. Basal view. R–S. SC2013.28.911, Albulidae gen. et sp. indet., left sagitta (reversed).
R. Inner view. S. Dorsal view. Scale bars: A–F = 5 mm; G–H = 3 mm; I–S = 1 mm.
European Journal of Taxonomy 984: 1–131 (2025)
78
Nearly all the isolated teeth are highly worn through in vivo use, and the remaining portion of these
specimens consists of the crown and a short basal area. In prole view, the crowns are high and basally
tapering (Fig. 23M, P), but their original unworn height is unknown. The crown is covered with a
thin layer of smooth enameloid that does not reach the tooth base. In occlusal view, the crown has a
circular outline, and the triturating surface largely consists of exposed dentine framed by thin enameloid
(Fig. 23L, O). In basal view, the circular pulp cavity is framed by a thick wall of dentine (Fig. 23N, Q).
The sagittae (Fig. 23R–S) are very small, with only a few exceeding 4 mm. They have a somewhat
oblong to elliptic outline (sensu Smale et al. 1995), and the margins are generally smooth. The inner
face is conspicuously convex and twisted, and a prominent long sulcus occurs primarily in the dorsal and
posterior regions. The sulcus has a wide, anterodorsally opening ostium that is lled with colliculum.
The caudal area has an anterior sub-horizontal portion and a posterior downturned portion that is usually
deeply excavated. A caudal keel is present on well-preserved specimens. The outer face is concave,
twisted (especially in adults), thickest postero-dorsally but thinning toward the anterior, and annual
growth rings are often visible to the naked eye.
Remarks
Albulid pharyngeal bones, isolated teeth, and otoliths are represented in our sample. These fossils cannot
be condently assigned to any particular genus, and we cannot ascertain whether the remains represent
more than one taxon. A single tooth recovered from the Glendon Limestone Member of the Byram
Formation of southwestern Alabama was identied as Albula sp. by Ebersole et al. (2021), and several
isolated teeth were reported from the late Rupelian Ashley Formation of South Carolina (Cicimurri
et al. 2022). Cicimurri & Knight (2009) also mentioned the occurrence of albulid teeth in the Chattian
Chandler Bridge Formation of South Carolina. Albulid otoliths have been reported from the Rupelian
Roseeld Formation in Louisiana (Stringer et al. 2001).
The small overall size of the Catahoula Formation otoliths is in stark contrast to those of Eocene albulids,
which approach 20 mm in length (Ebersole et al. 2019). Otoliths can attain even larger sizes, as a specimen
from the Eocene Clincheld Formation of Georgia measures 21.48 mm (Stringer et al. 2022a). Although
albulid otoliths occur within numerous Paleogene lithostratigraphic units within the Gulf Coastal Plain,
they are typically not abundant (Breard & Stringer 1995, 1999; Stringer & Breard 1997; Stringer &
Miller 2001; Schweitzer et al. 2014). Nolf & Stringer (2003) reported only ve specimens of Albula sp.
among the 5559 otoliths (0.09% of total sample) from the upper Eocene (primarily Priabonian) Yazoo
Clay in Louisiana, and albulid otoliths represented a slightly higher 1.33% of the total sample (n = 20)
from the Clincheld Formation (Stringer et al. 2022a). Far fewer otolith specimens were obtained from
the Catahoula Formation, but those of albulids constitute 2.47% of the sample.
Order Anguilliformes (sensu Inoue et al. 2010)
Suborder Congroidei Kaup, 1856
Family Congridae Kaup, 1856
Subfamily Bathymyrinae Böhlke, 1949
Genus Protanago Schwarzhans, Stringer & Takeuchi, 2024
Type species
Otolithus (Platessae) sector Koken, 1888
Protanago nonsector (Nolf & Stringer, 2003)
Fig. 24A–D
Ariosoma nonsector Nolf & Stringer, 2003: 7.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
79
Material examined
UNITED STATES OF AMERICA – Mississippi • 2 sagittae; Catahoula Formation; MMNS VP-8200.3
(Fig. 24A–B), MMNS VP-8713 (Fig. 24C–D).
Description
The sagitta outline is primarily oval (sensu Smale et al. 1995; also Nolf & Stringer 2003) due to the
presence of a prominent dorsal dome (Fig. 24A, C), which increases the height of the otolith relative
to its length. Height/length ratios are commonly 0.85. The margins are smooth and a posterodorsal
concavity is common. The inner face is generally smooth and evenly convex, although some irregular
depressions occur within the upper portion of the dorsal area. The sulcus is wide, slightly incised, and
undivided, with no clearly dened ostium and cauda (Fig. 24C). The sulcus begins very near the anterior
margin and extends approximately 85% the length of the inner face (Fig. 24A). The sulcus is lled with
colliculum except for the backward curving ostial channel. No ventral furrow is present. The outer face
is relatively smooth and convex (Fig. 24B, D), with the exception of an area near the posterior end,
where a shallow and dorsoventrally oriented depression occurs.
Remarks
Protanago nonsector otoliths from the Catahoula Formation have several characteristics in common
with Ariosoma as illustrated in Schwarzhans (2019a), but it diers in the lack of an S-shaped sulcus,
which is considered to be a diagnostic and autapomorphic characteristic of Ariosoma (Schwarzhans et al.
2024). Protanago nonsector (previously reported as Ariosoma nonsector) otoliths are widely distributed
across Paleogene sediments in the Gulf Coastal Plain, from Louisiana eastward into Georgia (Breard
& Stringer 1995; Nolf 2013; Ebersole et al. 2019; Stringer et al. 2022a). This species was abundant in
the upper Eocene (primarily Priabonian) Yazoo Clay in Louisiana, where it constituted 10.9% of the
Fig. 24. Protanago nonsector (Nolf & Stringer, 2003) (A–D), Congridae gen. et sp. indet. (E–F), and
Siluriformes indet. (G–K), remains. A–B. MMNS VP-8200.3, Protanago nonsector, right sagitta.
A. Inner view. B. Dorsal view. C–D. MMNS VP-8713, P. nonsector, left sagitta (reversed). C. Inner
view. D. Dorsal view. E–F. MMNS VP-12073, Congridae gen. et sp. indet., sagitta. E. Inner view.
F. Dorsal view. G–H. SC2013.28.750, Siluriformes indet., pectoral spine. G. Ventral view. H. Dorsal
view. I. MMNS VP-6651, Siluriformes indet., pectoral spine, ventral view. J–K. MMNS VP-7560,
Siluriformes indet., pectoral spine. J. Dorsal view. K. Posterior view. Scale bars: A–B, E–F = 2 mm;
C–D, I–K = 1 mm; G–H = 5 mm.
European Journal of Taxonomy 984: 1–131 (2025)
80
5599 specimens available (Nolf & Stringer 2003), and it has also been identied in small numbers in
the Eocene and Oligocene of Alabama (Ebersole et al. 2019, 2021). Protanago nonsector appears to be
the only species of this genus recorded outside of North America, as it has been documented in Italy
(Schwarzhans et al. 2024). Schwarzhans’ work on extant species of the family Congridae (Schwarzhans
2019b) indicates that careful review of Paleogene congrid otoliths is warranted.
One additional Catahoula Formation specimen (MMNS VP-8713) exhibits the salient features of
Protanago sp., but we cannot make a more accurate determination due to its poor preservation and
small size (juvenile). It is possible that the otolith represents P. nonsector, but we cannot rule out the
possibility that it belongs to a dierent, but closely related, species. The otolith is mentioned here for
completeness.
Congridae gen. et sp. indet.
Fig. 24E–F
Material examined
UNITED STATES OF AMERICA – Mississippi • 1 sagitta; Catahoula Formation; MMNS VP-12073.
Description
The sagitta is oval to somewhat elliptic in outline (sensu Smale et al. 1995) and the margins are
rather smooth. The height/length ratio is 0.55. The inner face varies from nearly at to very slightly
convex. The sulcus is undivided, slants very slightly in the posteroventral direction, and extends across
approximately 75% of the inner face. The sulcus tapers at the anterior and the posterior, and it appears to
reach the anterior margin, possibly through a shallow ostial channel. There is a conspicuous depressed
area, somewhat rectangular in shape, above the sulcus. The outer face is only slightly more convex than
the inner face.
Remarks
The otolith described above exhibits the typical congrid feature of having an undivided sulcus
(Fig. 24E). MMNS VP-12073 diers signicantly from specimens of Protanago nonsector (see above)
by having much less convex dorsal and ventral margins, with a H/L ratio of 0.55 vs 0.85 for the latter
taxon (compare to Fig. 24A, C). Specimen MMNS VP-12073 is similar to Protoanguilla?, a species
reported as Pseudophichthys glaber from middle Eocene to lower Oligocene deposits in Louisiana and
Mississippi (Nolf & Stringer 2003; Nolf 2013; Stringer et al. 2020c). Unfortunately, the anterior one-
quarter of the otolith is lacking and denitive identication to Protoanguilla? is not possible without
additional specimens. Schwarzhans et al. (2024) indicated that Pseudophichthys glaber diered from
the extant Pseudophichthys and erected the otolith-based genus Protoanguilla? for the taxon.
Unranked Clupeocephala Patterson & Rosen, 1977
Cohort Otocephala (sensu Nelson et al. 2016)
Superorder Ostariophysi (sensu Nelson et al. 2016)
Series Otophysi (sensu Fink & Fink 1981)
Subseries Siluriphysi Fink & Fink, 1996
Order Siluriformes Cuvier, 1816
Siluriformes fam., gen. et sp. indet.
Fig. 24G–K
Material examined
UNITED STATES OF AMERICA – Mississippi • 8 isolated n spines; Catahoula Formation; MMNS
VP-6651 (Fig. 24I), MMNS VP-7560 (Fig. 24J–K), SC2013.28.750 (Fig. 24G–H), SC2013.28.751 to
28.755.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
81
Description
The sample includes incomplete pectoral n spines potentially representing two morphologies. Three
specimens are the proximal end of right spines (i.e., Fig. 24G–H). These have a ared, shelf-like dorsal
process at the base, and this structure is roughly perpendicular to the spine length. The spine itself was
elongated, curving towards the posterior, distally tapering, and dorso-ventrally attened. The anterior
margin is convex, whereas the posterior margin is lined with small circular depressions. The dorsal
and ventral surfaces of the spine are convex and bear ne longitudinal striations. There is a triangular,
antero-ventrally located fossa at the spine base.
The remaining specimens are incomplete spines and ablated spine fragments. Specimens MMNS VP-
6651 (Fig. 24I) and MMNS VP-7560 (Fig. 24J–K) are large incomplete spines where MMNS VP-
6651 lacks its base and MMNS VP-7560 lacks its base and distal tip. Both specimens are elongated,
narrow and thin, and curving along their length. Additionally, MMNS VP-6651 preserves a bluntly
pointed distal tip. Both specimens exhibit numerous dorsal and ventral parallel ridges along their entire
preserved length. Furthermore, the anterior margin is rounded, whereas the posterior margin bears a
single row of basally directed, triangular denticles (Fig. 22J–K). Both specimens also show that these
denticles increase in size distally (Fig. 24I). The other ablated spine fragments exhibit a comparable
morphology.
Remarks
There are several extant catsh species within Ictaluridae and Ariidae that have ornamented n spines,
and we cannot condently identify our fragmentary specimens beyond the ordinal level. However,
two taxa may be represented based on the morphological variation we observed in the Catahoula
Formation sample, with one having a dimpled posterior margin and the other barbed. It is possible that
the morphologies represent the same spine, where the barbed section was located distal to the preserved
portions of the spines in our sample. Ariidae n spines have been reported from Eocene strata (Ebersole
et al. 2019) and Ictaluridae spines from the Late Miocene (Ebersole & Jacquemin 2018) and Pleistocene
(Jacquemin et al. 2016) of Alabama, but to our knowledge, the Catahoula Formation specimens represent
the rst North American Oligocene record of catshes. These shes were not identied in the Oligocene
marine paleofaunas of North and South Carolina (Case 1980; Müller 1999; Cicimurri & Knight 2009;
Cicimurri et al. 2022).
Barbed n spines could be confused with myliobatiform caudal spines, as both exhibit barbed margins.
However, myliobatiform caudal spines are barbed on their right and left lateral margins (as opposed to
only the posterior margin on our specimens), the dorsal surface is covered with enameloid (which is
lacking on catsh spines), and they are symmetrical in dorsal view.
Cohort Euteleostei Rosen, 1985
Superorder Acanthopterygii Greenwood et al., 1966
Series Percomorpha (sensu Nelson et al. 2016)
Subseries Ovalentaria Smith & Near in Wainwright et al., 2012
Order Istiophoriformes Betancur-R et al., 2013
Family Sphyraenidae Ranesque, 1815
Genus Sphyraena Artedi in Röse, 1793
Type species
Esox sphyraena Linnaeus, 1758, Extant, Mediterranean Sea.
European Journal of Taxonomy 984: 1–131 (2025)
82
Sphyraena sp.
Fig. 25A–F
Material examined
UNITED STATES OF AMERICA – Mississippi • 609 isolated teeth; Catahoula Formation; MMNS VP-
9048, SC2013.28.531 to 28.536, SC2013.28.537 (50 teeth), SC2013.28.538 (8 teeth), SC2013.28.539
(15 teeth), SC2013.28.540 (7 teeth), SC2013.28.541 to 28.544, SC2013.28.545 (Fig. 25A–C),
SC2013.28.546 (20 teeth), SC2013.28.547 (5 teeth), SC2013.28.548 (2 teeth), SC2013.28.549 (109 teeth),
SC2013.28.550 to 28.557, SC2013.28.558 (Fig. 25D–F), SC2013.28.559 (79 teeth), SC2013.28.560
(35 teeth), SC2013.28.561 (10 teeth), SC2013.28.562 (12 teeth), SC2013.28.563 (10 teeth),
SC2013.28.564 (226 teeth).
Description
Two tooth morphologies are represented in our sample. The rst includes tall teeth measuring up to
12 mm in height. These teeth have a sinuous prole, with the labial margin formed into a sharp,
smooth carina that extends from the tooth base to the crown apex (Fig. 25A). This carina is more convex
along the basal one-half, after which it is posteriorly directed and may or may not have a slight vertical
rise to the apex. The posterior margin is convex and thickest basally, but it thins apically. In prole this
margin is straight to concave along the lower two-thirds, but apically it can be straight to weakly convex.
The apex bears a diminutive posterior barb, and on some teeth this barb is represented only by a short
anterior carina. Relatively pristine specimens exhibit vertical striations or wrinkling at the postero-basal
surface. In anterior/posterior view, the tooth is straight to slightly medially curved (Fig. 25B). The basal
attachment surface is weakly concave, and its outline is generally teardrop-shaped on smaller specimens
and oval on larger specimens (Fig. 25C).
Teeth of the second morphology are lanceolate and highly labio-lingually compressed (Fig. 25D). In
anterior/posterior view, the crown is straight to weakly medially curved (Fig. 25E). The anterior and
posterior margins are formed into sharp and smooth carinae that extend from the base to the apex. Well-
preserved teeth show that the crown is covered with thin enameloid that can be striated basally, but
enameloid largely remains only at the anterior and posterior carinae. The labial and lingual crown faces
are weakly convex, but the basal portion of the lingual face is somewhat more convex. In basal view,
the attachment surface is concave, and the outline is elliptical (Fig. 25F). There are two slightly diering
morphotypes, with one being taller and antero-posteriorly narrower than the other. The taller teeth are
more often medially curved, whereas the shorter teeth are rather straight. Additionally, the cutting edges
of taller teeth are proportionally longer and the apex more pointed compared to the shorter and wider
teeth.
Remarks
Based on extant specimens of Sphyraena barracuda (Walbaum, 1792) that we examined (SC2018.3.1;
MSC 43215), the tall teeth with an anterior carina and posterior apical barb are laniary teeth that were
located at the anterior end of the premaxilla or dentary. The lanceolate specimens occurred within the
cheek regions of the palatine or dentary. Ebersole et al. (2019) and Ballen (2020) have indicated that
tooth morphologies among extant Sphyraenidae are taxonomically distinctive, but intraspecic variation
is not well documented. There is no evidence contradicting our conclusion that various Catahoula
Formation Sphyraena morphologies are conspecic. Regarding the laniary teeth, all the well-preserved
specimens, from the smallest (3 mm in height) to the largest (12 mm) exhibit a smooth anterior cutting
edge, diminutive postero-apical barb, and postero-basal vertical striations. Specimen SC2018.3.1 also
indicates that somewhat taller and narrower lanceolate specimens from the Catahoula Formation were
from the anterior dentary, whereas the slightly shorter and wider teeth were located on the palatine. The
Catahoula Formation sample includes teeth with and without striations and ridges, and we observed this
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
83
phenomenon in the jaws of the extant Sphyraena spp. that we examined. Crown ornamentation therefore
does not appear to be taxonomically signicant.
Santini et al. (2015) demonstrated the existence of three Sphyraena lineages by the late Eocene, and
the age of the Catahoula Formation specimens is close to the timing of radiation of the S. obtusata
Cuvier, 1829 and S. sphyraena (Linnaeus, 1758) species groups (with each group containing several
species). Extant representatives of both species groups currently inhabit the Gulf of Mexico (Hoese &
Moore 1998). Ballen (2020) presented a listing of fossil Sphyraena species, including several from the
Oligocene. Sphyraena intermedia Bassani, 1889 and S. pannonica Weiler, 1938 were based on skeletal
material that included crania, but neither author provided tooth descriptions. Sphyraena tyrolensis von
Meyer, 1863 is known from a dentary and various isolated teeth. Although von Meyer (1863) mentioned
the occurrence of basal striations on laniary teeth (“Fangzahn” therein), he did not mention the presence
of an apical barb, and the laniary tooth of the gured specimen (pl. 50 gs 7–8) is broken apically. The
remainder of the teeth along the ramus of this specimen are otherwise comparable to any species of
Sphyraena. Ebersole et al. (2021) documented similar Sphyraena sp. dentary teeth from the Rupelian
Byram Formation in Alabama, and Ebersole et al. (2024a) identied both laniary and dentary teeth
Fig. 25. Sphyraena sp. (A–F), Syacium sp. (G–H), Acanthocybium sp. (I–K), Scomberomorus sp. (L–N),
and Labridae gen. et sp. indet. (O–T), remains. A–C. SC2013.28.545, Sphyraena sp., laniary tooth.
A. Labial view. B. Posterior view. C. Basal view. D–F. SC2013.28.558, Sphyraena sp., tooth. D. Lingual
view. E. Carinal view. F. Basal view. G–H. MMNS VP-12074, Syacium sp., left otolith (reversed).
G. Inner view. H. Dorsal view. I–K. SC2013.28.579, Acanthocybium sp., tooth. I. Lingual view.
J. Carinal view. K. Basal view. L–N. SC2013.28.572, Scomberomorus sp., tooth. L. Lingual view.
M. Carinal view. N. Basal view. O–Q. SC2013.28.596, Labridae gen. et sp. indet., tooth mass. O. Oral
view. P. Aboral view. Q. Prole view. R–T. SC2013.28.597, Labridae gen. et sp. indet., tooth mass.
R. Oral view. S. Aboral view. T. Prole view. Scale bars: A–F, I–N = 5 mm; G–H = 1 mm;
O–Q = 4 mm; R–T = 2 mm.
European Journal of Taxonomy 984: 1–131 (2025)
84
from the Rupelian Red Blu Clay in the same state. Leidy (1855) named S. major based on specimens
recovered from the Ashley River of South Carolina. He did not provide a description of the teeth and
only mentioned that the material was collected from the Ashley River. The fossils in question may have
been derived from the Ashley Formation (Rupelian), but the source unit could be older or younger (see
Albright et al. 2018). We refrain from making a species determination, because we cannot accurately
compare the Catahoula Formation material to all the other named species due to the lack of described
morphological features.
Order Pleuronectiformes Bleeker, 1859
Superfamily Pleuronectoidea Ranesque, 1815
Family Cyclopsettidae Campbell et al., 2019
Genus Syacium Ranzani, 1842
Type species
Syacium micrurum Ranzani, 1842, Extant.
Syacium sp.
Fig. 25G–H
Material examined
UNITED STATES OF AMERICA – Mississippi • 3 sagittae; Catahoula Formation; MMNS VP-12074,
GLS otolith comparative collection (2 specimens).
Description
The sagittae have a primarily square outline (sensu Smale et al. 1995). The margins are generally smooth
but can be variable and irregular. The inner face is slightly convex and smooth (Fig. 25H). A highly
specialized, fusiform sulcus slants downward from the posterodorsal margin to almost the anteroventral
margin (Fig. 25G). The sulcus is widest just behind its midline but is narrower at the anterior and
posterior ends. Although the sulcus extends across approximately 75% of the inner face, it is narrow and
represents roughly 20% of the height. The sulcus is divided into ostial and caudal areas. The ostium is
located near the lower portion of the anterior and anteroventral margins but does not reach the margins.
The ostium is tapered and almost pointed at the anterior end. The cauda is longer and wider than the
ostium, and the anterior of the cauda is tapered, whereas the center portion is enlarged. The cauda is
excavated slightly deeper than the ostium. The ostium and cauda are conspicuously connected or fused,
and the structure is lled with colliculum. A marked circumsulcal depression extends from above the
ostium, around the cauda, and ends below the ostium. The circumsulcal depression forms an elevated
attened area for the fusiform sulcus. A ventral furrow is not present. The outer face is fairly at on the
dorsal and ventral areas, but is slightly convex in the center.
Remarks
The Syacium sp. otoliths from the Catahoula Formation are very similar to the Syacium sp. sagittae
from the Rupelian Glendon Limestone Member of the Byram Formation of Alabama (Ebersole et al.
2021). This genus appears to be rare in Paleogene strata across the Gulf and Atlantic coastal plains of the
USA, but it is somewhat more common (although still rare) during the Neogene (Stringer 1992; Nolf &
Stringer 2003; Nolf 2013; Stringer et al. 2017; Stringer & Bell 2018; Ebersole et al. 2019; Stringer &
Shannon 2019; Stringer & Hulbert 2020).
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
85
Order Scombriformes Ranesque, 1810
Suborder Scombroidei Bleeker, 1859
Family Scombridae Ranesque, 1815
Subfamily Scombrinae Ranesque, 1815
Tribe Scomberomorini Starks, 1910
Genus Acanthocybium Gill, 1862
Type species
Cybium solandri Cuvier & Valenciennes, 1832, Extant.
?Acanthocybium sp.
Fig. 25I–K
Material examined
UNITED STATES OF AMERICA – Mississippi • 3 isolated teeth; Catahoula Formation; SC2013.28.577,
SC2013.28.578, SC2013.28.579 (Fig. 23I–K).
Description
The teeth have a lanceolate prole. The anterior and posterior margins are formed into sharp smooth
carinae, each of which extends from the tooth base and coalesces at a rounded apex (Fig. 25I). In
anterior and posterior views, the crown is nearly vertical but has a slight lingual curvature, and the
carina is located closer to the labial face (Fig. 25J). The lingual face is more convex than the labial
face, particularly at the lower one-third. In basal view, the carinae are conspicuously dierentiated from
the main body of the crown due to the medially convex lingual face, and a deep pulp cavity is visible
(Fig. 25K).
Remarks
These specimens dier from the lanceolate Sphyraena sp. teeth (see above) and from teeth assigned to
Scomberomorus sp. (see below) by being much thicker labio-lingually and having much more convex
labial and (especially) lingual faces. The Catahoula Formation teeth are comparable to those occurring
in Acanthocybium premaxillae and a dentary (SC2016.1.14) that we examined from the late Rupelian
Ashley Formation of South Carolina. The premaxillary teeth of the Ashley Formation taxon are two
to three times larger than those of the dentary, but the dentary teeth are equally convex labially and
lingually. Based on these observations, the Catahoula Formation teeth were located in the premaxilla.
The Catahoula Formation teeth are also similar to specimens identied as Palaeocybium from the
Eocene of Alabama (Ebersole et al. 2019), as well as to the Oligocene Neocybium parvidentatum
Monsch & Bannikov, 2012 of Europe (see also Leriche 1908). However, Palaeocybium possesses two
rows of teeth in the jaws (Monsch 2005), which cannot be determined from the isolated teeth in our
Catahoula Formation sample. To our knowledge, Palaeocybium is unknown beyond the Eocene. Jaws
of Neocybium and the South Carolina Acanthocybium have only a single row of teeth, with those of the
former perhaps being less convex and more widely separated in the jaws (Monsch & Bannikov 2012).
We tentatively assign the Catahoula Formation specimens to Acanthocybium due to dental similarities
between the Mississippi fossils and the South Carolina Oligocene Acanthocybium.
Genus Scomberomorus Bleeker, 1859
Type species
Scomber regalis Bloch, 1793, Extant.
European Journal of Taxonomy 984: 1–131 (2025)
86
Scomberomorus sp.
Fig. 25L–N
Material examined
UNITED STATES OF AMERICA – Mississippi • 175 isolated teeth; Catahoula Formation;
SC2013.28.565 to 28.571, SC2013.28.572 (Fig. 25L–N), SC2013.28.573 (2 teeth), SC2013.28.574 (101
teeth), SC2013.28.575 (50 teeth), SC2013.28.576 (14 teeth).
Description
The teeth are broadly triangular, with larger specimens measuring 11 mm in apico-basal height and
7 mm in width (antero-posterior). The labial and lingual crown faces are convex, but the lingual face,
particularly near the base, is more so. In anterior/posterior view, the crown is medially curved but may
be straight (Fig. 25M). The anterior and posterior margins are formed into smooth, sharp, convex cutting
edges, and in labial view these edges converge to a rounded apex. It appears that enameloid once covered
the crown surface, but this is generally only preserved at the cutting edges of the teeth in our sample.
In basal view, the tooth has a thin D-shaped outline, and the basal surface is at to weakly concave
(Fig. 25N).
Remarks
The teeth described above are similar to Sphyraena sp. non-laniary teeth (see above) but can be
dierentiated by their thicker crown that is asymmetrical in basal view (compare Fig. 25N to 25F).
The lingual face of Scomberomorus sp. teeth is much more convex than the labial face, and the crown
is more medially curved. In contrast, the Sphyraena sp. crown is thinner, straighter (in carinal view),
and the labial and lingual crown faces are slightly but equally convex. The teeth of Scomberomorus sp.
dier from those of ?Acanthocybium sp. (see above) by their labio-lingually thinner crown (compare
Fig. 25N to K) and primarily at basal surface. Although two species of Scomberomorus have been
identied from Eocene deposits in Alabama (see Ebersole et al. 2019), the teeth in our sample represent
the rst occurrence of this taxon within any Oligocene strata in the Gulf Coastal Plain of the USA.
Order Labriformes Kaufman & Liem, 1982
Family Labridae Cuvier, 1816
Labridae gen. et sp. indet.
Fig. 25O–T
Material examined
UNITED STATES OF AMERICA – Mississippi • 12 isolated teeth; Catahoula Formation; SC2013.28.603
(12 specimens) • 7 tooth masses; Catahoula Formation; SC2013.28.596 (Fig. 25O–Q), SC2013.28.597
(Fig. 25R–T), SC2013.28.598 to 28.602.
Description
Our sample includes fragments of pharyngeal plates and isolated teeth. The pharyngeal plate fragments
consist of tightly packed teeth of diering sizes that form a roughly contiguous surface. In cross section,
up to four sets of replacement teeth are visible (Fig. 25Q, T). Teeth were apparently not replaced at a
regular rate, as newer (replacement) teeth are intermingled with older functional teeth (Fig. 25O, R).
In prole view, individual teeth can be low with a convex occlusal surface or high with a globular
appearance. In occlusal/basal view, they have a circular to oval outline. Teeth essentially consist of a
very thick enameloid cap with an open pulp cavity free of dentine (Fig. 25P, S).
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
87
Remarks
The unusual arrangement of the teeth within the jaw plates, as well as the composition of individual teeth,
facilitates separating wrasse specimens from those of other, similar-looking taxa (see below). Fossil
occurrences of Labridae are sparse, but Cicimurri et al. (2022) reported specimens from the Rupelian
Ashley Formation of South Carolina, and Cicimurri & Knight (2009) mentioned their occurrence in the
Chattian Chandler Bridge Formation. Labrid molecular divergence times were estimated by Cowman et
al. (2009), who postulated that the extant lineages within this family largely diverged within the Miocene.
This suggests that the labrid elements in our Catahoula Formation sample represent an unrecognized
stem-member of the lineage.
Order Perciformes (sensu Nelson et al. 2016)
Family Haemulidae Gill, 1885
Genus Allomorone Dante & Frizzel in Frizzell & Dante, 1965
Type species
Orthopristis duplex Girard, 1858, Extant.
Allomorone sp.
Fig. 26A–B
Material examined
UNITED STATES OF AMERICA – Mississippi • 1 sagitta; Catahoula Formation; MMNS VP-12060.
Description
MMNS VP-12060 has an elliptic outline (sensu Smale et al. 1995) with a rather prominent, somewhat
blunt rostrum with excisura. The inner face is broadly and evenly convex with a conspicuous sulcus
(heterosulcoid type). The sulcus extends approximately 80% of the length of the inner face (Fig. 26A).
The ostium is relatively narrow and subquadrate in shape. The height of the ostium is only slightly
greater than the height of the cauda, but the length of the ostium is signicantly shorter than the cauda.
The narrow cauda is approximately 2.5 times as long as the ostium. The dorsal and ventral margins of
the cauda are horizontal and essentially parallel. The posterior portion of the cauda is bent downward.
A ridge-like crista superior occurs above the cauda and a linear, depressed area is located above the crista
superior. There may have been a ventral furrow, but this region is not well preserved on the specimen in
our sample. The outer face is concave and has a slightly irregular surface (Fig. 26B).
Remarks
The Catahoula Formation Allomorone sp. sagitta appears to be very closely related to what was previously
reported as Orthopristis americana (Koken, 1888) from the Gulf Coast upper Eocene (Jackson Group),
a taxon that was rst reported by Koken (1888) as Otolithus (Carangidarum) americana. However,
Schwarzhans et al. (2024) considered Allomorone dierent from Orthopristis because of the much
shorter, downward section of the cauda that terminates away from the post-ventral margin on the
sagitta of Allomorone. Unfortunately, the somewhat eroded specimen available to us is not sucient
to make a specic determination. Allomorone sp. otoliths are much more common in the Gulf Coastal
Plain compared to the Atlantic Coastal Plain, as Müller (1999) only reported three specimens from the
Eocene (as “Genus a. Orthopristis sp.”) in a sample of over 12 000 fossil otoliths collected from middle
Eocene to Pliocene deposits in the Atlantic Coastal Plain. In contrast, Allomorone americana was more
abundant in the upper Eocene (primarily Priabonian) Yazoo Clay otolith assemblage from Copenhagen,
European Journal of Taxonomy 984: 1–131 (2025)
88
Louisiana, representing 4.35% of the total specimens in a sample (Nolf & Stringer 2003; reported as
Orthopristis americana). Green (2002) reported a signicant occurrence of A. americana (18.17% of
the total number of otolith specimens) in the middle Eocene (Bartonian) Moodys Branch Formation
at the Heison Landing locality along the Ouachita River in Caldwell Parish, Louisiana (shown as
O. americana). Ebersole et al. (2021) did not report O. americana from the Rupelian Glendon Limestone
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
89
Member of the Byram Formation in Alabama, and it has not been reported from younger formations in
the Gulf and Atlantic coastal plains (Stringer & Bell 2018; Stringer & Shannon 2019; Stringer & Hulbert
2020; Stringer & Starnes 2020; Stringer et al. 2020a, 2022b).
Family Lutjanidae Gill, 1861
Lutjanidae gen. et sp. indet.
Fig. 26C–I
Material examined
UNITED STATES OF AMERICA – Mississippi • 112 isolated teeth; Catahoula Formation; MMNS
VP-7685 (4 teeth), MMNS VP-7685.1 (Fig. 26C–D), MMNS VP-7685.2 (Fig. 26E–F), SC2013.28.677
to 28.682, SC2013.28.683 (100 teeth) • 1 jaw; Catahoula Formation; MMNS VP-8341 (Fig. 26G–I).
Description
Specimen MMNS VP-8341 is an incomplete left dentary measuring roughly 4 cm in length and
1.5 cm in maximum height. In labial view, the oral and aboral margins are moderately convex. Much
of the labial face is convex and smooth, and there are several large fenestrae penetrating the surface
(Fig. 26G). Aborally, the jaw is thin and developed into a ridge-like structure bearing conspicuous
oblique ridges. The anterior jaw margin is vertical and straight. Slightly posterior to this margin is a
conspicuous constriction where the jaw measures only 7.5 mm in height. The lingual surface is smooth
(Fig. 26I). In oral view, the jaw is convex antero-posteriorly, it is thickest at its blunt anterior end, and
there is a single row of large tooth alveoli anked by a medial tooth patch (Fig. 26H). All of the large
alveoli occur along the labial margin and have a circular outline. The sizes of the alveoli demonstrate
that the largest teeth were located anteriorly, but teeth decreased slightly in size towards the posterior
end of the tooth row. The lingual tooth patch is widest anteriorly but narrows posteriorly, and it consists
of numerous tiny and circular alveoli (Fig. 26H–I).
The isolated teeth attain up to 5 mm in total height. They are conical and straight to postero-medially
curved to varying degrees (Fig. 26E and 26C, respectively). Well-preserved specimens show that the
Fig. 26 (page 88). Allomorone sp. (A–B), Lutjanidae gen. et sp. indet. (C–I), Aplodinotus distortus
Nolf, 2003 (J–M), A. gemma (Koken, 1888) (N–S), Sciaenidae gen. et sp. indet. (T–W), Sciaena?
pseudoradians (Dante & Frizzell in Frizzell & Dante, 1965) (X–AA), and Sciaena? radians (Koken,
1888) (BB–CC), remains. A–B. MMNS VP-12160, Allomorone sp., left otolith (reversed). A. Inner
view. B. Dorsal view. C–D. MMNS VP-7685.1, Lutjanidae gen. et sp. indet., tooth. C. Prole view.
D. Basal view. E–F. MMNS VP-7685.2, Lutjanidae gen. et sp. indet., tooth. E. Prole view. F. Basal
view. G–I. MMNS VP-8341, Lutjanidae gen. et sp. indet., left dentary. G. Labial view. H. Oral view.
I. Lingual. J–K. MMNS VP-7458.1, Aplodinotus distortus, left otolith (reversed). J. Dorsal view.
K. Inner view. L–M. MMNS VP-7456.1, A. distortus, left otolith (reversed). L. Inner view. M. Dorsal
view. N–O. MMNS VP-8712.2, A. gemma, right otolith. N. Inner view. O. Dorsal view. P–Q. MMNS
VP-8430.1, A. gemma, right otolith. P. Inner view. Q. Dorsal view. R–S. MMNS VP-8430.2, A. gemma,
left otolith (reversed). R. Inner view. S. Dorsal view. T–U. MMNS VP-8712.3, Sciaenidae gen. et sp.
indet., left otolith (reversed). T. Inner view. U. Dorsal view. V–W. MMNS VP-8712.4, Sciaenidae gen. et
sp. indet., right otolith. V. Inner view. W. Dorsal view. X–Y. MMNS VP-7445, Sciaena? pseudoradians,
left otolith (reversed). X. Inner view. Y. Dorsal view. Z–AA. MMNS VP-8711.1, S.? pseudoradians,
left otolith (reversed). Z. Inner view. AA. Dorsal view. BB–CC. MMNS VP-12076, Sciaena? radians,
left otolith (reversed). BB. Inner view. CC. Dorsal view. Scale bars: A–B, N–O, T–U, BB–CC = 1 mm;
C–D, P–Q, X–Y = 5 mm; E–F, R–S = 4 mm; G–I = 2 cm; J–M, V–W = 3 mm; Z–AA = 2 mm.
European Journal of Taxonomy 984: 1–131 (2025)
90
entire crown was covered by enameloid, but this is often only preserved on the upper one-half of the
tooth. Interestingly, the apparently thinner enameloid covering along the lower one-half of the tooth
is often a lighter color shade compared to the darker color of the upper one-half. Fine vertical uting
may occur on the posterior crown surface. Specimens that are ablated at the base show that the internal
dentine is layered. Teeth have a circular basal outline, and the deep pulp cavity is framed by a thick wall
of dentine (Fig. 24D, F).
Remarks
We compared the jaw and teeth described above to those of numerous extant shes occurring in the Gulf
of Mexico and found that they are very similar to representatives of Lutjanidae, particularly Lutjanus.
The Catahoula Formation teeth are nearly identical to the large anterior teeth occurring on the premaxilla
of L. jocu (Bloch & Schneider, 1801) (MSC 49315, SC uncurated specimen), but they are also similar to
equivalent teeth of L. synagris (Linnaeus, 1758) (MSC 49478) and L. campechanus (Poey, 1860) (MSC
45233, MSC 49309). The fossil jaws dier by having a lingual tooth patch consisting of numerous tiny
alveoli, as opposed to there being one or two rows of moderately-sized teeth in this region (as observed
on the extant taxa noted above). Several interpretations could account for the variation in tooth size
that we observed in the Catahoula Formation sample, including intra- and/or interspecic variation. It
is possible that dierences in tooth size are related to ontogeny within a single species, as the teeth of
a 10 cm TL L. campechanus (MSC 45233) are simply smaller versions of teeth occurring in a 57.5 cm
TL individual (MSC 49309). Additionally, the teeth along the jaws of one individual become smaller
antero-posteriorly within the jaws. Although it is possible that the teeth and dentary available to us
represent dierent species, there is currently no denitive evidence that more than one lutjanid taxon
occurs within the Catahoula Formation.
Ebersole et al. (2019) reported teeth like those described above as Osteoglossidae indet. (i.e., bony
tongues), derived from middle Eocene deposits in Alabama. However, a reexamination of these teeth as
part of the current study leads us to believe that the Eocene teeth instead belong to Lutjanidae, a taxon
that is common in the Gulf of Mexico today (see Hoese & Moore 1998). In contrast, extant osteoglossids
are freshwater sh occurring in South America, Africa, and Southeast Asia to northern Australia (Nelson
et al. 2016). Nevertheless, the lutjanid teeth in our Catahoula Formation sample represent the rst
Oligocene occurrence of this taxon in the Gulf Coastal Plain of the USA.
Order Acanthuriformes (sensu Nelson et al. 2016)
Suborder Sciaenoidei Betancur-R et al., 2013
Family Sciaenidae Cuvier, 1829
Genus Aplodinotus Ranesque, 1819
Type species
Aplodinotus grunniens Ranesque, 1819, Extant.
Aplodinotus distortus Nolf, 2003
Fig. 26J–M
Material examined
UNITED STATES OF AMERICA – Mississippi • 19 sagittae; Catahoula Formation; MMNS VP-7449,
MMNS VP-7461, MMNS VP-7456.1 (Fig. 26L–M), MMNS VP-8002.2, MMNS VP-8200.2, MMNS
VP-8201.2, MMNS VP-8712 (8 specimens), MMNS VP-7458.1 (Fig. 26J–K), MMNS VP-7458.2,
SC2013.28.760, SC2013.28.761, SC2013.28.793.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
91
Description
The sagitta outline is somewhat rectangular (sensu Smale et al. 1995) in smaller specimens. Specimens
larger than 5 mm show a marked distortion from the antero-dorsal to the posteroventral, which noticeably
aects the overall shape. Furthermore, some of the larger specimens may show a hypertrophical
development of the posteroventral margin, and there may also be an expansion of the antero-dorsal area.
The margins are typically smooth. The inner face is somewhat convex and characterized by a very large,
prominent heterosulcoid-type sulcus. The height of the cauda is slightly over 20% of the height of the
ostium, and the cauda has a horizontal and downturned component. The outer face is not as convex as
the inner face.
Remarks
Ontogenetic variation is apparent in our A. distortus otolith sample. For example, the ostium on juvenile
specimens is much smaller in height, and the ventral margin of the sulcus has no expansion compared to
adult specimens, where the ostium extends from near the antero-dorsal margin well down into the ventral
eld and is largest at the posterior portion. The ventral margin of the adult ostium curves distinctly upward
toward the anterior margin and is subparallel to the anteroventral margin in larger specimens, and the
posteroventral portion extends underneath the cauda. There are signicant ontogenetic changes in the
cauda, with the horizontal portion being signicantly greater in length on smaller specimens compared
adult specimens. Additionally, the downturned portion may have a greater length on large specimens,
exceeding approximately 10 mm (see also Nolf 2003: pl. 4 g. 4). The outer face ranges from nearly
at on small specimens to slightly more convex in larger specimens, and there is also greater convexity
in the posterior portion than in the anterior. With respect to species identication, there is typically a
wide area between the posterior of the ostium and the downturned portion of the cauda in Aplodinotus
distortus, which is noticeably wider than that on A. gemma (see below). Aplodinotus distortus lacks the
inframedian tip on the posterior margin occurring on Sciaena? radians sagittae.
Nolf (2003) named Aplodinotus distortus based on specimens from the Byram Formation (Oligocene,
Rupelian) at the Keyes Iron and Metal locality near Vicksburg, Mississippi, USA. Specimens were
recovered from other Byram Formation exposures in the Vicksburg vicinity, and otoliths were also
obtained from the Roseeld Marl Beds of the Roseeld Formation (Oligocene, Rupelian) in Catahoula
Parish, Louisiana (Stringer & Worley 2003). One of the current authors (GLS) has observed that
specimens 10 mm in length are common in several of the Byram Formation localities in the Vicksburg,
Mississippi area.
Although only 18 specimens of Aplodinotus distortus were recovered (including one tentatively referred
to the species) from the Catahoula Formation at Jones Branch (4.4% of the otolith sample), the taxon
is more abundant than Sciaena? radians but much less common than S.? pseudoradians and A. gemma.
Like S.? pseudoradians, S.? radians, and Aplodinotus gemma, A. distortus is widespread in the Gulf
Coastal Plain and is known from many Oligocene formations in Louisiana and Mississippi (Nolf 2003,
2013; Stringer & Worley 2003; Worley 2004).
Aplodinotus gemma (Koken, 1888)
Fig. 26N–S
Otolithus (Sciandarum) gemma Koken, 1888: 281.
Material examined
UNITED STATES OF AMERICA – Mississippi • 46 sagittae; Catahoula Formation; MMNS VP-7447,
MMNS VP-7452, MMNS VP-7456.2, MMNS VP-7458.3, MMNS VP-7459.3, MMNS VP-8201.1,
MMNS VP-8430 (2 specimens), MMNS VP-8430.1 (Fig. 26P–Q), MMNS VP-8430.2 (Fig. 26R–S),
European Journal of Taxonomy 984: 1–131 (2025)
92
MMNS VP-8712.2 (Fig. 26N–O), SC2013.28.771, SC2013.28.779, GLS otolith comparative collection
(33 specimens).
Description
The sagitta outline is somewhat square to discoidal (sensu Smale et al. 1995). Larger specimens (greater
than 5 mm) have a greater dorso-ventral height, and a more discoidal shape compared to smaller ones.
The margins are generally smooth. The inner face is generally strongly convex and characterized by
a very large, prominent heterosulcoid-type sulcus. The ostium extends from near the antero-dorsal
margin well down into the ventral eld and is largest at the posterior portion. The ventral margin of the
ostium curves only slightly upward toward the anterior margin. The posteroventral portion of the ostium
extends underneath the cauda. Generally, there is a very short distance between the posterior of the
ostium and the downturned portion of the cauda. The height of the cauda constitutes approximately 25%
of the height of the ostium, and the cauda has a horizontal and downturned component. The downturned
portion of the cauda tends to be slightly curved. The outer face is only slightly convex, and that of larger
specimens is often more irregular than on smaller specimens.
Remarks
Koken (1888) mentioned this species from the “Vicksburg; Red Blu; Jackson River, Mississippi”
and “Jackson and Vicksburg Beds,” but the exact stratigraphic occurrence(s) for his specimens cannot
be ascertained. However, Aplodinotus gemma is known from Oligocene formations (Mint Spring and
Byram formations) in the vicinities of Vicksburg and Jackson in Mississippi (Nolf 2003, 2013; Stringer
et al. 2020c). Specimens of A. gemma are also known from the Roseeld Marl Beds of the Roseeld
Formation (Oligocene, Rupelian) in Catahoula Parish, Louisiana (Stringer & Worley 2003; Worley
2004) and from the Glendon Limestone Member of the Byram Formation of Alabama (Ebersole et al.
2021). The 46 A. gemma specimens from the Catahoula Formation constitute 11.2% of the total number
of otoliths in the sample. This abundance is only exceeded by Sciaena? pseudoradians (see below).
Schwarzhans (1993) proposed the otolith-based genus Frizzelithus to accomodate A. gemma. However,
this designation was based on only 20 large specimens, some of which were eroded. The present study
has the advantage of including hundreds of sciaenid otoliths from the Oligocene of Alabama, Mississippi,
and Louisiana, as well as an ontogenetic series. Whereas g. 144 in Schwarzhans (1993) represents
Aplodinotus gemma, gs 145–146 are signicantly dierent in the shape of the ostium and the salient
inframedian posterior tip, and are attributed to Sciaena? radians (Nolf 2003, 2013). The otolith in g.
147 is much more elongate, has a greater distance between the ostium and downturned portion of the
cauda, and the shape of the ostium diers greatly from that in g. 144. The former matches Sciaena?
a. pseudoradians from the upper Eocene and Sciaena? pseudoradians from the Oligocene of the Gulf
Coast. Several of the sciaenids of the Oligocene appear to be closely related to the extant Aplodinotus
grunniens Ranesque, 1819 (Nolf 2003, 2013; Ebersole et al. 2021; Fuelling et al. 2022), which is
extremely common in eastern North America, and the Catahoula specimens are placed in this genus.
Genus Sciaena Linnaeus, 1758
Type species
Sciaena umbra Linnaeus, 1758, Extant.
Sciaena? pseudoradians (Dante & Frizzell in Frizzell & Dante, 1965)
Fig. 26X–AA
Corvina pseudoradians Dante & Frizzel in Frizzell & Dante, 1965: 707–708.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
93
Material examined
UNITED STATES OF AMERICA – Mississippi • 134 sagittae; Catahoula Formation; MMNS VP-
7445 (Fig. 26X–Y), MMNS VP-7446 (3 specimens), MMNS VP-7448 (3 specimens), MMNS VP-
7451, MMNS VP-7453 (4 specimens), MMNS VP-7459.2, MMNS VP-7460.1, MMNS VP-8200.1
(9 specimens), MMNS VP-8711 (4 specimens), MMNS VP-8711.1 (Fig. 26Z–AA), MMNS VP-
8935, SC2013.28.757, SC2013.28.758, SC2013.28.762, SC2013.28.764 to 28.770, SC2013.28.772,
SC2013.28.774 to 28.776, SC2013.28.778, SC2013.28.781 to 28.783, SC2013.28.786, SC2013.28.794,
SC2013.28.801, GLS otolith comparative collection (84 specimens).
Description
The outline of Sciaena? pseudoradians is primarily rectangular (sensu Smale et al. 1995), but the anterior
and ventral margins are somewhat convex and rounded. The margins are typically smooth, and the inner
face is moderately convex. The inner face is characterized by a very large, prominent heterosulcoid-
type sulcus. The ostium is exceptionally large in length and height, especially compared to the cauda.
The ostium extends from near the anterodorsal margin well down into the ventral eld and is largest
at the posterior portion. The posteroventral portion of the ostium extends noticeably underneath the
cauda in larger specimens. The height of the cauda is only about 25% of the height of the ostium
(i.e., much narrower in comparison). The cauda has a distinctive horizontal and downturned component.
The horizontal portion appears to shorten in length compared to the downturned portion during
ontogenetic development (Nolf 2003: pl. 2 gs 3–6). The outer face increases in irregularity with growth
and is convex, but not as much as the inner face.
Remarks
Dante & Frizzell in Frizzell & Dante (1965) rst named Sciaena? pseudoradians as Corvina pseudo-
radians based on specimens from the Byram Formation (Oligocene, Rupelian) in Mississippi, USA, and
the holotype (USNM 23368) was illustrated by Nolf (2003: g. 6). Sciaena? pseudoradians is known
from numerous Oligocene formations in Mississippi, Louisiana, and Alabama (Nolf 2003; Stringer &
Worley 2003; Worley 2004; Stringer et al. 2020c; Ebersole et al. 2021), and its presence is therefore
not unexpected in the Catahoula Formation. Sciaena? pseudoradians is the most abundant otolith-based
species in our Catahoula Formation sample (n = 134), including seven additional specimens tentatively
assigned to the species. Nolf & Stringer (2003) identied Sciaena? a. pseudoradians from the upper
Eocene (primarily Priabonian) Yazoo Clay based on 78 specimens of the 5293 otoliths they examined
(1.47% of the sample). Sciaena a. pseudoradians was reported from the Eocene Clincheld Formation
in Georgia, where it represented 8% of the total number of specimens in the bulk sample. Lin & Nolf
(2022) noted that S.? pseudoradians is known primarily from the lower Oligocene of the Gulf Coastal
Plain, but they also noted that “imperfectly preserved” otoliths are known from the Eocene of Texas and
Louisiana (Bartonian and Priabonian).
Sciaena? radians (Koken, 1888)
Fig. 26BB–CC
Otolithus (Sciaenidarum) radians Koken, 1888: 280.
Material examined
UNITED STATES OF AMERICA – Mississippi • 3 sagittae; Catahoula Formation; MMNS VP-8934,
MMNS VP-12076 (Fig. 26BB–CC), SC2013.28.763.
Description
The outline of the sagitta is somewhat rectangular (sensu Smale et al. 1995), but the anterior, dorsal,
and ventral margins are slightly convex and rounded to various degrees (Fig. 26BB). The margins are
European Journal of Taxonomy 984: 1–131 (2025)
94
typically smooth, and there is a highly characteristic inframedian tip on the posterior margin. The inner
face is moderately convex (Fig. 26CC) and characterized by a very large and prominent heterosulcoid-
type sulcus. The ostium is noticeably large in its length and height. The ostium extends from near the
anterodorsal margin well into the ventral eld and is largest at the posterior portion. The ventral margin
of the ostium curves distinctly upward toward the anterior margin and is subparallel to the anteroventral
margin. The posteroventral portion of the ostium extends conspicuously underneath the cauda, especially
on larger specimens. The height of the cauda is about 30% of the height of the ostium. The cauda has
a characteristic horizontal and downturned component. The horizontal and downturned portions are of
similar length, but the downturned portion is usually slightly longer on the larger specimens (Nolf 2003:
pl. 4 gs 1–3). The outer face becomes somewhat more irregular on larger specimens. The outer face
is nearly at on small specimens but is more convex on larger specimens, although it is not nearly as
convex as the inner face.
Remarks
Koken (1888) originally named Otolithus (Sciaenidarum) gemma based on specimens labeled only as
“Vicksburg” from Mississippi, USA. Unfortunately, Koken’s type suite actually contained three dierent
species, including Sciaena? radians, S.? pseudoradians, and Aplodinotus gemma (see discussion in Nolf
2003). Only three specimens of Sciaena? radians were recovered from the Catahoula Formation (less
than 1% of the total specimens), and the species is the least common of the sciaenids within the otolith
assemblage. Although “S.?” radians is widespread in the Gulf Coastal Plain and is known from many
Oligocene formations in Mississippi, Louisiana, and Alabama (Nolf 2003, 2013; Stringer & Worley
2003; Worley 2004; Stringer et al. 2020c), the species is similarly rare in those assemblages.
Sciaenidae gen. et sp. indet.
Figs 26T–W, 27
Material examined
UNITED STATES OF AMERICA – Mississippi • 5761 isolated teeth; Catahoula Formation;
SC2013.28.809 (Fig. 27F–H), SC2013.28.810, SC2013.28.811 (Fig. 27I–K), SC2013.28.812,
SC2013.28.813 (79 teeth), SC2013.28.842 (5678 teeth) • 16 pharyngeals; Catahoula Formation;
SC2013.28.684 (Fig. 27C–E), SC2013.28.685 to 28.689, SC2013.28.690 (9 specimens),
SC2013.28.691 • 192 sagittae; Catahoula Formation; MMNS VP-7457 (2 specimens), MMNS VP-
7460.2, MMNS VP-8712.3 (Fig. 26T–U), MMNS VP-8712.4 (Fig. 26V–W), MMNS VP-8933
(2 specimens), MMNS VP-8933.1 (Fig. 27A–B), SC2013.28.759, SC2013.28.773, SC2013.28.777,
SC2013.28.780, SC2013.28.784, SC2013.28.785, SC2013.28.787, SC2013.28.790, SC2013.28.792,
SC2013.28.798 to 28.800, SC2013.28.806 (6 specimens), SC2013.28.807 (12 specimens), GLS otolith
comparative collection (154 specimens).
Description
The best-preserved sciaenid jaw element is an edentulous lower right pharyngeal (Fig. 27C–E). In aboral
and oral views, the bone has a somewhat triangular outline. The symphyseal margin is rather straight and
would have abutted (but not fused) with the left pharyngeal. The labial margin is relatively straight and
intersects the symphyseal margin at a blunt anterior point. Posteriorly the labial margin extends away
from the symphysis, and the distal margin is convex. The oral surface bears alveoli and broken tooth
bases that are loosely arranged into rows that parallel the labial margin. The teeth are largest anteriorly,
but teeth located at the distal one-third of the jaw were only about one-half as large. In symphyseal view,
the symphyseal surface is high, especially medially, and the anterior end of the bone curves dorsally. The
ventral strut that buttressed the bone against the cleithrum is incompletely preserved.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
95
Isolated teeth consist of a moderately high crown and base that comprises one-third or less of the total
tooth height (Fig. 27F–K). The crown is covered by a relatively thin layer of smooth enameloid that
ends abruptly at the base (Fig. 27G, J). The occlusal surface of unworn teeth is weakly to moderately
convex, but the crowns of worn teeth exhibit a at surface with exposed dentine. The occlusal outline
is polygonal (i.e., four-sided to six-sided; Fig. 27F, I), and the sides of the crown are at and vertical. In
basal view, a small and deep pulp cavity is framed by a thick wall of dentine (Fig. 27H, K).
Remarks
Herein included within undetermined sciaenid shes are isolated teeth, pharyngeal tooth plates, and
poorly preserved otoliths. The pharyngeal bones are largely abraded and incomplete, often hindering
our ability to determine their location in the jaw let alone the taxon represented. The isolated teeth
are reminiscent of several sciaenid species, and we could not conclusively determine that they are
representative of any one of the taxa we identied by otoliths. The otoliths are not well enough preserved
for us to assign them to a particular genus (i.e., Fig. 26T), and it is unclear whether they represent one of
the taxa described herein. All of these specimens are included here for completeness.
Order Spariformes (sensu Nelson et al. 2016)
Family Sparidae Ranesque, 1818
Genus Diplodus Ranesque, 1810
Type species
Sparus annularis Linnaeus, 1758, Extant.
Fig. 27. Sciaenidae gen. et sp. indet., remains. A–B. MMNS VP-8933.1, right sagitta. A. Inner
view. B. Dorsal view. C–E. SC2013.28.684, lower right pharyngeal. C. Aboral view. D. Oral view.
E. Symphyseal view. F–H. SC2013.28.809, tooth. F. Occlusal view. G. Prole view. H. Basal view.
I–K. SC2013.28.811, tooth. I. Occlusal view. J. Prole view. K. Basal view. Scale bars: A–B, F–K = 1
mm; C–E = 5 mm.
European Journal of Taxonomy 984: 1–131 (2025)
96
Diplodus sp.
Fig. 28
Material examined
UNITED STATES OF AMERICA – Mississippi • 183 isolated teeth; Catahoula Formation;
SC2013.28.643 (Fig. 28A–C), SC2013.28.644 to 28.650, SC2013.28.651 (Fig. 28D–F), SC2013.28.652,
SC2013.28.653, SC2013.28.654 (2 teeth), SC2013.28.655 (11 teeth), SC2013.28.656 (16 teeth),
SC2013.28.657 (20 teeth), SC2013.28.658 (21 teeth), SC2013.28.659 (20 teeth), SC2013.28.660
(13 teeth), SC2013.28.661 (37 teeth), SC2013.28.662 (17 teeth), SC2013.28.663 (15 teeth).
Description
Isolated teeth are highly laterally compressed (labio-lingually) and approximately as tall (apico-basally)
as they are elongated (mesio-distally). The crown constitutes the upper two-thirds of a tooth and is
covered with smooth enameloid. The labial crown face is weakly convex and the lingual face weakly
concave (Fig. 28C, F). In mesial/distal view, the crown may be lingually curved. In labial/lingual
view, unworn teeth have a roughly rhomboidal outline. The mesial margin may be uniformly convex
or sinuous, with the basal portion being most convex but transitioning apically to concave. The distal
margin is sinuous, with the basal portion being most convex but transitioning apically to concave. The
apical part of the crown is formed into a cusp-like projection (Fig. 28B). The crown tapers basally
towards a narrow bony projection, and the crown foot is marked by the enameloid boundary (Fig. 28E).
Remarks
Our sample includes teeth that are worn to varying degrees. These teeth demonstrate that the cuspidate
crown apex exhibits the initial signs of in vivo wear (polished and somewhat attened wear facet), and
with continued use the cusp is worn completely away to a at, relatively horizontal surface that reveals
the internal dentine (compare Fig. 28A to D). Some teeth are worn nearly to the crown base, indicating
a long period of tooth retention within the jaws and possibly pointing to a durophagous diet.
Diplodus sp. was recently reported from the upper Rupelian Givhans Ferry Member of the Ashley
Formation in Dorchester County, South Carolina by Cicimurri et al. (2022). These teeth are easy to
distinguish from those of all other bony shes by their laterally compressed crowns with sinuous anterior
and posterior margins. Our Catahoula Formation teeth represent the rst occurrence of this taxon from
the Gulf Coastal Plain of the USA.
Genus Sparus Linnaeus, 1758
Type species
Sparus aurata Linnaeus, 1758, Extant.
Fig. 28. Diplodus sp., teeth. A–C. SC2013.28.643, tooth. A. Outer view. B. Inner view. C. Anterior
view. D–F. SC2013.28.651, tooth. D. Outer view. E. Inner view. F. Anterior view. Scale bars = 1 mm.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
97
Sparus? cf. elegantulus (Koken, 1888)
Fig. 29A–B
Otolithus (Pagelli) elegantulus Koken, 1888: 279.
Material examined
UNITED STATES OF AMERICA – Mississippi • 1 sagitta; Catahoula Formation; MMNS VP-12077.
Description
The outline of MMNS VP-12077 is essentially a square. The margins are primarily irregular with varying
indications of lobation, sinuosity, and smoothness. The height/length ratio is about 0.65. The inner
face tends to be slightly and fairly evenly convex (Fig. 29B). A prominent heterosulcoid-type sulcus
extends across approximately 85% of the inner face (Fig. 29A). The sulcus, which is located slightly
dorsal, is essentially horizontal except for a very small, downwardly exed posterior of the cauda. The
ostium opens on the anterior margin. The dorsal and ventral margins of the ostium are approximately
parallel. The posteroventral portion of the ostium does not extend underneath the cauda. The ostium
is approximately 40% of the length of the cauda. The height of the cauda is approximately 50–60% of
the height of the ostium. Approximately 80% of the cauda is horizontal with about 20% downturned.
The downturned portion is approximately 45° from horizontal. There is an irregularly shaped, dorsal
depression above the cauda and a faint ventral furrow located away from the ventral margin. The outer
face is slightly concave and may be slightly irregular.
Remarks
The single specimen was tentatively assigned to Sparus elegantulus due to its preservation. The species
was originally identied by Koken (1888) in the Gulf Coast Plain of the USA. Sparus? elegantulus is
known from the Eocene of Alabama, Georgia, Louisiana, and Mississippi (Nolf & Stringer 2003; Nolf
2013; Stringer et al. 2022a). Within Oligocene deposits, the species has previously been reported from
the Rupelian Glendon Limestone (NP22/23) in Mississippi (Stringer et al. 2020c) and from the Glendon
Limestone Member of the Byram Formation (NP23) of Alabama by Ebersole et al. (2021). In the latter
occurrence, the species was relatively abundant and represented 12.06% of the total otolith sample.
Sparidae gen. et sp. indet.
Fig. 29C–J
Material examined
UNITED STATES OF AMERICA – Mississippi • 1041 isolated teeth; Catahoula Formation;
SC2013.28.664 to 28.666, SC2013.28.667 (6 specimens), SC2013.28.668 (Fig. 29I–J), SC2013.28.669,
SC2013.28.670 (3 specimens), SC2013.28.671 (3 specimens), SC2013.28.672, SC2013.28.673
(4 specimens), SC2013.28.674 (4 specimens), SC2013.28.675, SC2013.28.676 (4 specimens),
SC2013.28.903 (Fig. 29C–E), SC2013.28.904 (Fig. 29F–H), SC2013.28.907, SC2013.28.910 (1007
specimens).
Description
In addition to Diplodus sp., at least two other sparid tooth morphotypes occur in the Catahoula Formation.
One morphotype, shown in Fig. 29C–H, is represented by low- and high-crowned specimens. Low-
crowned specimens have a weakly to moderately convex occlusal surface (compare Fig. 29D to G) and
circular to ovate occlusal outline (compare Fig. 29C to F). High-crowned specimens are cylindrical
with a very convex occlusal surface and circular occlusal outline. Regardless of crown height, there is a
conspicuous basal band that is distinguished by a weak cingulum (Fig. 29G). In basal view, a large pulp
cavity is framed by a thick dentine wall with a thick external enameloid covering (Fig. 29E, H).
European Journal of Taxonomy 984: 1–131 (2025)
98
Another morphotype is like that shown in Fig. 29I–J. These teeth are also of variable height, but all have
a very convex labial face and less convex lingual face. In prole view, the crown is medially curved and
the labial and lingual faces are asymmetrically divided by blunt carinae that may or may not reach the
crown base (Fig. 29I). In basal view, the tooth base has a circular to slightly oval outline, and the central
pulp cavity varies in size but is framed by a wall of dentine covered with thick external enameloid
(Fig. 29J).
Remarks
Teeth within the jaws of extant Sparidae that we examined can be dierentiated into incisiform, lateral,
and molariform types. Incisiform teeth are located along the anterior margin of tooth plates, whereas
lateral teeth occur along the lateral margins (i.e., Fig. 29I). Molariform teeth occur on the main body
of a pharyngeal tooth plate and form most of a triturating surface (i.e., Fig. 29C, F). The lateral teeth
identied as Diplodus sp. (see above) are easily separated from those assigned to Sparidae indet. by their
thinness and sinuous anterior and posterior margins.
Order Lophiiformes Garman, 1899
Family Lophiidae Ranesque, 1810
Lophiidae gen. et sp. indet.
Fig. 30
Material examined
UNITED STATES OF AMERICA – Mississippi • 229 teeth, MMNS VP-6995 (10 teeth),
SC2013.28.581 (Fig. 30A–C), SC2013.28.582 (Fig. 30G–I), SC2013.28.583, SC2013.28.584
(Fig. 30D–F), SC2013.28.585, SC2013.28.586, SC2013.28.587 (Fig. 30J–L), SC2013.28.588 (8 teeth),
SC2013.28.589 (15 teeth), SC2013.28.590 (36 teeth), SC2013.28.591 (15 teeth), SC2013.28.592
(51 teeth), SC2013.28.593 (87 teeth).
Description
The isolated teeth are tall, needle-like, and, in prole view, posteriorly curving to varying degrees
(Fig. 30A, D, G, J). The crown is conical to somewhat laterally compressed, with the anterior face of the
latter morphology being narrower than that of the posterior face (Fig. 30B, E, H). In anterior/posterior
Fig. 29. Sparidae gen. et sp. indet., remains. A–B. MMNS VP-12077, left sagitta (reversed). A. Inner
view. B. Dorsal view. C–E. SC2013.28.903, tooth. C. Occlusal view. D. Prole view. E. Basal view.
F–H. SC2013.28.904, tooth. F. Occlusal view. G. Prole view. H. Basal view. I–J. SC2013.28.668,
tooth. I. Prole view. J. Basal view. Scale bars: A–B = 1 mm; C–J = 2 mm.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
99
view, the crown may be weakly medially curved. Enameloid is not evident on any specimens, but the
posterior surface bears numerous closely spaced, parallel vertical ridges extending up to three-quarters
of the tooth height. The teeth have a labial carina that extents the height of the tooth. In basal view, the
tooth has a circular to elliptical outline, and a circular pulp cavity is deep and framed by a thin wall of
dentine (Fig. 30C, F, I, L).
Remarks
The fossil material we examined compares very well to an extant Lophius americanus Cuvier &
Valenciennes, 1837 in the MSC collection (MSC 50198), as well as illustrations of Miocene material
reported from elsewhere (Purdy et al. 2001: g. 66c; Schultz 2006: pl. 1 gs 1b, 2b). The lophiid teeth
are easily distinguished from the teeth of all other Catahoula Formation teleosts by their tall, needle-
like and curved crown, posterior longitudinal ridges, labial carina, and circular basal outline. Additional
extant lophiid comparative specimens are needed to further elucidate the taxonomic anities of these
remains.
Order Tetraodontiformes Berg, 1940
Suborder Tetraodontoidei Nelson et al., 2016
Family Tetraodontidae Bonaparte, 1831
Tetraodontidae gen. et sp. indet.
Fig. 31
Material examined
UNITED STATES OF AMERICA – Mississippi • 6 isolated jaws; Catahoula Formation; SC2013.28.604,
SC2013.28.605 (Fig. 31A–C), SC2013.28.606, SC2013.28.607 (2 specimens), SC2013.28.608
(Fig. 31D–F).
Description
Specimen SC2013.28.608 is a right premaxilla measuring 4 mm in antero-posterior length, 1.5 mm
in dorso-ventral height, and 1 mm in greatest medio-lateral width. In aboral view, the jaw is thickest
Fig. 30. Lophiidae gen. et sp. indet., remains. A–C. SC2013.28.581, tooth. A. Labial view. B. Posterior
view. C. Basal view. D–F. SC2013.28.584, tooth. D. Lingual view. E. Posterior view. F. Basal view.
G–I. SC2013.28.582, tooth. G. Labial view. H. Posterior view. I. Basal view. J–L. SC2013.28.587,
tooth. J. Labial view. K. Posterior view. L. Basal view. Scale bars = 5 mm.
European Journal of Taxonomy 984: 1–131 (2025)
100
mesially but tapers distally, it has an arcuate appearance (convex labially), and the internal bony structure
has a spongy appearance (Fig. 31F). In labial view, the jaw surface is convex and appears to consist of
a uniform layer of shiny tissue (Fig. 31E). In oral view, much of the triturating surface is rather thin
and the labial margin is sharp. In symphyseal view, the articular surface (for the left premaxilla) bears
a series of fossae that are separated by thin dentine lamellae. Additionally, what appears to be a circular
triturating pad occurs on the oral surface, just distal to the symphysis (Fig. 31D).
Also included in our sample are jaw fragments that are comprised of stacked rows of teeth. In labial
view, the teeth are very low (apico-basally) and elongated (mesio-distally). Tooth length varies
among the teeth in a row, and they have roughly rectangular outlines. The teeth in each row may butt
directly against each other, or the tapered ends may overlap the end of the preceding/succeeding teeth
(Fig. 31B). The teeth in successive rows may not perfectly overlie those in previous rows, and younger
teeth may be longer or shorter than the tooth immediately below. In lingual view, the teeth are embedded
in osteodentine (Fig. 31A).
Remarks
The specimens are very small, but SC2013.28.608 is similar to the premaxillae of fossil tetraodontoid
taxa that have been described. The premaxilla of the Pliocene Spheroides hyperostosis Tyler et al., 1992
bears a single triturating tooth on the oral surface, whereas that of the Oligocene Archaeotetraodon
winterbottomi Tyler & Bannikov, 1994 has three. The premaxilla of Eotetraodon Tyler, 1980 is
incompletely known, but the dentary or E. tavernei Tyler & Bannikov, 2012 bears two triturating teeth.
Lagocephalus striatus Aguilera et al., 2018 was recently described from the Middle Miocene strata of
Panama, but the morphology of the triturating surface of the premaxilla is presently unknown. Similarly,
the premaxilla morphology of Leithaodon sandroi Carnevale & Tyler, 2015 from the Middle Miocene
of Austria is unknown. Unfortunately, the knob-like triturating pad of SC2013.28.608 is ablated and it is
dicult to determine whether the triturating surface consists of one or two teeth. Additional specimens,
particularly cranial material, are necessary to accurately determine the generic anity of the Catahoula
Formation puersh.
The jaws of two other groups of tetraodontiform shes, Diodontidae and Triodontidae, have anterior
beak-like structures, but these dier from the Catahoula Formation specimens by being composed of
alternating stacked rows of sub-triangular teeth with pointed apices (Thiery et al. 2017). The Catahoula
Formation puersh specimens are signicant because, to our knowledge, they represent the rst
Oligocene record of Tetraodontidae in the Western Hemisphere.
Fig. 31. Tetraodontidae gen. et sp. indet., remains. A–C. SC2013.28.605, jaw. A. Lingual view. B.
Labial view. C. Aboral view. D–F. SC2013.28.608, right premaxilla. D. Lingual view. E. Labial view.
F. Aboral view. Scale bars: A–C = 1 mm; D–F = 2 mm.
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
101
Teleostei fam., gen. et sp. indet.
An additional 1127 teleost remains include isolated jaws like premaxillae and dentaries (n = 17), other
cranial bones like quadrates and vomerines (n = 8), isolated teeth (n = 843), n spines (n = 210), and
vertebrae (n = 49). Our comparative sample of extant marine taxa did not allow us to assign these
remains beyond Teleostei and are not discussed in further detail. These specimens were included in the
total number of sh remains examined in our sample, but not counted among the remains identied to
at least the ordinal level.
Discussion
Our evaluation of 13 551 sh fossils from the Catahoula Formation indicates that a rather diverse late
Oligocene (Chattian) fauna is preserved within the fossiliferous horizon we sampled. The taxa we
identied are largely based on teeth, jaw elements, scales, and n spines, but our knowledge of the
paleofauna is supplemented by a sample of 409 otoliths. Details regarding the Catahoula Formation
sh assemblage are provided below, and the chondrichthyan and teleost taxa we identied are listed in
Appendix 1 and Appendix 2, respectively.
Characteristics of the Catahoula sh assemblage
The 3605 elasmobranch teeth, scales, and caudal spines within our Catahoula Formation sample
represent 29 taxa belonging to ve orders and nineteen families. Sharks are more diverse than rays
in this assemblage, with 19 taxa belonging to 12 families compared to 10 taxa within six families,
respectively. Of the sharks, Carcharhiniformes is the most diverse group (12 taxa in ve families),
followed by Lamniformes (four genera in four families) and Orectolobiformes (three genera in three
families). Myliobatiformes is the more diverse ray group and is represented by at least seven taxa,
whereas there are three genera (within two families) of Rhinopristiformes.
Sharks and rays possess a polyphyodont dentition where teeth within the various les are continuously
replaced throughout the lifetime of an individual (Rasch et al. 2016). The replacement rates, faster
or slower, could impact our ability to determine abundance or rarity within the Catahoula Formation
elasmobranch assemblage. Tooth replacement is relatively fast in some sharks, like Ginglymostoma, and
may occur within ten days (Luer et al. 1990). Conversely, it may take more than a month for a tooth to
be replaced in Triakis (Smith et al. 2009). Tooth abundance could also be aected by other factors, like
regular death of individuals and scattering of large numbers of teeth, rather than regular replacement by
living individuals. However, we can only presume that the numbers of specimens we recovered for each
taxon reects their scarcity or abundance within the Catahoula Formation fossil bed. Furthermore, the
abundance/scarcity of a taxon within the Catahoula Formation is likely related to environmental and/
or dietary preferences for the taxa we identied. Although we cannot rule out the possibility that our
sample is inuenced by preservation and/or collecting biases, we believe that the latter was mitigated by
the small mesh sizes employed to recover remains (0.4 mm), which in addition to small elasmobranch
and teleost fossils also includes foraminifera tests and ostracod valves.
Of the shark component, Carcharhiniformes is the most common group based on isolated teeth
(n = 1729), followed by Lamniformes (n = 245) and Orectolobiformes (n = 21). Continuing this further,
Carcharhinus acuarius (daggernose shark) is the most abundant elasmobranch, not just in the shark
component but within the total elasmobranch sample (n = 986, 49% of the shark component and 27%
of the total elasmobranch sample). Other common sharks include Hemipristis intermedia sp. nov.
(n = 196, roughly 10% of the shark sample), Carcharhinus elongatus (n = 287, 14% of the shark sample),
and Carcharias cuspidatus (n = 240, 12% of the shark sample).
European Journal of Taxonomy 984: 1–131 (2025)
102
Of the batoids, teeth of taxa with durophagous (crushing) dentitions are common but largely represented
by lateral teeth and broken symphyseal teeth. These teeth represent at least three genera, but the highly
worn and/or broken nature of 49.5% of the total sample (326 teeth out of 658 specimens) inhibits our
ability to determine whether other taxa are represented. It does appear that presumed lter-feeding rays,
represented by two genera (Plinthicus sp., Paramobula fragilis), are rare components of the Catahoula
Formation sh assemblage, as they are represented by a total of three teeth. Hypanus? heterodontus
sp. nov. is the most abundant of the Catahoula Formation batoids, and the 578 teeth we recovered
comprise over 36% of the total batoid component. Rhynchobatus teeth are also common, with 246 teeth
representing 15% of the batoid sample.
Of the 9937 Catahoula Formation bony sh fossils we examined, 96% of the sample consists of skeletal
remains, particularly teeth but to a lesser extent jaws, scales, and n spines. The remaining 4% of the
sample includes otoliths. Together, these fossils indicate that at least 20 unequivocal bony sh taxa
occur in the Catahoula Formation. One order, Siluriformes, is based on n spines, but ten families have
been identied based on teeth, jaws and/or scales. Three of these families, Albulidae, Sciaenidae, and
Sparidae, are also known by otoliths. We presume that the teeth and jaw bones generically assigned to
Sciaenidae and Sparidae represent any of the seven genera within these families that we identied by
otoliths, although we cannot discount the presence of other species or even genera. Three additional
families, Congridae, Cyclopsettidae, and Haemulidae, are known only by otoliths.
As noted above, there is a fundamental dierence in the occurrence of bony sh teeth and otoliths in
the Catahoula Formation sh assemblage. It is improbable, if not impossible, to equate the number of
individual teeth to the number of individual sh represented in our sample. Bony shes are primarily
polyphyodont, and the tooth loss and replacement system is not well documented at the generic and
especially at the species level. This is primarily due to a lack of obvious patterning in the mouth, accurately
determining loss of teeth, and maintaining specimens long enough in a controlled environment to observe
and document loss and replacement (i.e., Carr et al. 2021). Much of the literature on polyphyodont
bony shes has emphasized taxa with extreme morphological heterodonty (Fraser et al. 2012; Conway
et al. 2015; Bemis et al. 2019; Kolmann et al. 2019). However, shes with dissimilar tooth shapes, like
laniary teeth, appear to have independent replacement patterns, and replacement may be maintained
by a spatially and temporally driven development network (Wakita et al. 1977; Huysseune & Meunier
1994; Huysseune 1995; Bemis et al. 2005; Trapani et al. 2005; Carr et al. 2021). There appears to be
a single pattern of tooth replacement in bony shes with a simple dentition morphology, and there is
evidence that some of the bony shes with a simple dentition can shed as many as 3% of their total
number of teeth per day (Carr et al. 2021). This phenomenon can profoundly impact the interpretation
of taxonomic abundance based on isolated teeth in teleost paleofaunas.
In contrast, otoliths are paired elements and thus every right sagitta represents an individual sh
(Schwarzhans 1978; Nolf 1985; Nolf & Stringer 1992; Campana 2004). In some instances, it has even
been possible to determine the right and left otoliths from the same individual sh (Girard et al. 2005).
With these premises set, it is evident that sh teeth are the most abundant of the bony sh skeletal
remains in the Catahoula Formation at the Jones Branch locality (Appendix 2). The 5761 teeth from
Sciaenidae are the most numerous of any of the sh skeletal remains identied at least to the ordinal
level, including elasmobranchs (47% of the total sh assemblage, 65% of the bony sh tooth sample)
and indicate that these shes were common in the ancient Catahoula Formation environment. This is
corroborated by the high proportion of sciaenid otoliths we identied (96% of the otolith sample). Other
taxa are known by relatively few numbers of specimens and therefore appear to be uncommon to rare,
including Cyclopsettidae (n = 3 otoliths), ?Acanthocybium sp. (n = 3 teeth), Tetraodontidae (n = 6 beak
fragments), and Siluriformes (n = 8 n spines). Albulidae (boneshes) is represented by relatively few
teeth (n = 48) and even fewer otoliths (n = 9), but we are not surprised by this apparent rarity given
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
103
the behavior, abundance, and distribution of these shes in the present-day Gulf of Mexico (Hoese &
Moore 1998; Froese & Pauly 2023) and their trophic niche (Crabtree et al. 1998; Reeves 2011).
Snyder & Burgess (2016) characterized the preferred habitat as seagrass and carbonate sand bottoms in
clear shallow water (often < 2 m). Those authors also noted that albulids are often found alone and feed
primarily on crabs, shrimp, snails, clams, and worms.
Several of the bony sh taxa we identied, like Sphyraena sp., Scomberomorus sp., Lophiidae, and
Sparidae (including Diplodus sp.), are represented by relatively large numbers of teeth. These taxa
represent roughly 24% (n = 609), 7% (n = 175), 9% (n = 229), and 48% (n = 1224) respectively, of the
remaining non-sciaenid teeth in our Catahoula Formation sample. Interestingly, we did not recover any
otoliths of the former three taxa, but this may not be surprising given that sh like Sphyraena are upper
trophic-level predators, and their otoliths are typically very rare in otolith assemblages (Nolf 1985,
2013; Nolf & Stringer 1992, 2003; Stringer et al. 2020b, 2023). For example, Schwarzhans (2019a)
reported only two Sphyraena sp. specimens in his exhaustive study of approximately 25 000 otoliths
from the Cenozoic of New Zealand. As the small otolith sample from the Catahoula Formation would
make the occurrence of Sphyraena otoliths even less likely, the relative abundance of Sphyraena teeth
warrants further comment.
Froese & Pauly (2023) reported that extant Sphyraena (Sphyraenidae) typically occur in brackish and
marine waters in tropical and subtropical settings. Of the three species inhabiting the Atlantic Ocean
and Gulf of Mexico, S. barracuda (Edwards, 1771), S. borealis DeKay, 1842, and S. guachancho
Cuvier, 1829, their common depth ranges are 3–30 m, 10–65 m, and 0–100 m, respectively (Froese
& Pauly 2023; Page et al. 2023). The rst two species tend to be more solitary, but S. guachancho is
reported as a schooling species that commonly occurs in turbid coastal waters over muddy bottoms.
Additionally, Blaber (1982) reported that S. barracuda individuals under two years of age inhabit
estuarine environments where they prey upon smaller shes. Either or both scenarios could explain the
abundance of Sphyraena sp. teeth in the Catahoula Formation sh assemblage. Further discussion of the
depositional environment of the Catahoula Formation fossil bed is provided below.
Biostratigraphic and biogeographic implications of the Catahoula Formation sh assemblage
Our study is the rst to focus on vertebrate marine fossils occurring in the Catahoula Formation, and
this is the most comprehensive report on Oligocene shes from the Gulf Coastal Plain. Although
elasmobranchs and to a lesser extent teleosts have been described from Oligocene units of Virginia
(Müller 1999) and South Carolina (Cicimurri & Knight 2009; Cicimurri et al. 2022), a systematic
evaluation of Oligocene sh assemblages from the Gulf Coastal Plain has yet to be undertaken. The taxa
that have been reported from other lithostratigraphic units in Mississippi, as well as in Louisiana and
Alabama, are largely based on preliminary evaluations (i.e., Ebersole et al. 2021, 2024a) or focused only
on otoliths (i.e., Worley 2004).
The Catahoula Formation sh assemblage is slightly younger than that of the Ashley Formation (Rupelian,
ca 28.5 Ma), and slightly older than or temporally equivalent to the Chandler Bridge Formation (Chattian,
ca 24.5 Ma) of South Carolina. The Old Church Formation of Virginia is somewhat older (29 Ma) than
the sh assemblage reported from the Ashley Formation (Cicimurri et al. 2022; Weems et al. 2022). At
the generic level, a comparison of the elasmobranch taxa from each of these units revealed a striking
similarity, as 75% of the taxa occurring in the Catahoula Formation are also found in the Oligocene of
the Atlantic Coastal Plain (Müller 1999; Cicimurri & Knight 2009; Cicimurri et al. 2022). At the species
level, several of those from the Catahoula Formation occur in the Atlantic Coastal Plain, as, for example,
Paramobula fragilis, which is present in the Old Church, Ashley, and Chandler Bridge formations.
Alternatively, there are signicant dierences among the units, as Galeocerdo platycuspidatum
sp. nov. occurs in Mississippi but G. aduncus is found in the Chandler Bridge Formation (Cicimurri &
European Journal of Taxonomy 984: 1–131 (2025)
104
Knight 2009). It is interesting to note that daggernose shark teeth are common in both the Catahoula
Formation and Old Church Formation (based on SC2020.43), and this taxon also occurs in the Rupelian
(NP23) Roseeld Formation of Louisiana (as Isogomphodon sp. in Cicimurri & Ebersole 2021). Some
of the dierences are likely related to environmental variations, as the Catahoula and Chandler Bridge
Formations appear to have been deposited in rather shallow water, whereas the Ashley Formation formed
further oshore at a depth of around 100 m (Cicimurri & Knight 2009; Cicimurri et al. 2022). Temporal
age may also be a factor, as the lithostratigraphic units may be separated by up to several million years
of time.
Our knowledge of the Oligocene bony shes from the Atlantic and Gulf coastal plains is far from
complete and largely based on either tooth-based taxa or otolith-based taxa. Some Catahoula Formation
bony sh genera also occur in the Ashley Formation, including Sphyraena sp., Acanthocybium sp., and
Scomberomorus sp. Additionally, the families Albulidae, Labridae, Sciaenidae, and Sparidae occur in
both units and, except for Sciaenidae, have also been reported from the Chandler Bridge Formation
(Cicimurri & Knight 2009; Cicimurri et al. 2022). Based on the teleost teeth contained within SC2020.43,
all the families listed above also occur in the Old Church Formation. In their preliminary note on fossil
shes from the Glendon Limestone Member of the Byram Formation (Rupelian, Zone P19, NP23) of
Alabama, Ebersole et al. (2021) documented teeth of Albula sp. and Sphyraena sp.
Oligocene bony sh diversity within many of the aforementioned units increases signicantly when
otolith-based taxa are included. Otoliths have been described from Oligocene units in Alabama,
Louisiana, and Mississippi (Stringer et al. 2001, 2020c; Stringer & Worley 2003; Worley 2004; Ebersole
et al. 2021), but otoliths are unknown from the Oligocene of South Carolina. Additionally, the taxa
Müller (1999) reported from the Old Church Formation of Virginia need revision due to the obsolete
classication scheme utilized, a task currently being undertaken by several of the present authors.
Currently, the sciaenids Aplodinotus gemma, A. distortus, and Sciaena? radians are known only from
the Oligocene of the Gulf Coastal Plain (Nolf 2003, 2013; Stringer & Mixon 2005; Ebersole et al. 2021;
Fuelling et al. 2022; Lin & Nolf 2022). Unfortunately, none of the other Catahoula Formation otolith-
based taxa are very diagnostic due to their extensive biostratigraphic ranges.
During our study of the Catahoula Formation sh assemblage, we found that otoliths were rare in
the larger mesh size fractions (> 4 mm mesh size or #5 soil screen), and most of the specimens were
obtained from ner fractions generally between 0.4 mm and 0.85 mm mesh (#20 to #40 soil screen). The
implications of the size disparities are discussed further below. Worley (2004) provided a comprehensive
otolith study based on 446 otoliths recovered from the Oligocene Roseeld Formation (Rupelian, Zone
P20, Zone NP23) from three sites in Catahoula Parish, Louisiana. Interestingly, the number of otoliths
per kilogram of matrix was higher in the Roseeld Formation compared to the Catahoula Formation.
The Roseeld Formation otolith assemblage is nearly twice as diverse as the Catahoula Formation
(18 taxa versus 10 taxa), but two disparities stand out. Although both assemblages contain sciaenids,
these sh comprise 36.32% of the total Roseeld Formation assemblage, whereas they constitute 96% of
the Catahoula Formation assemblage. Additionally, the size of the Roseeld Formation otoliths ranges
from 5 mm to 12 mm in length, but more than 99% of the Catahoula Formation specimens are less than
5 mm in length. These signicant size dierences in the otolith assemblages are believed to be directly
related to paleoenvironmental conditions. The Roseeld Formation was shown to be more inuenced by
shallow, normal marine conditions (Worley 2004), whereas the Catahoula Formation otoliths indicate
much shallower environments, including estuarine. The unusual size distribution of the otoliths in the
Catahoula Formation assemblage is discussed in greater detail below.
The otolith taxa reported by Ebersole et al. (2021) from the Rupelian Glendon Limestone Member of
the Byram Formation of Alabama included nine taxa, despite the much smaller matrix sample collected
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
105
and number of otoliths recovered (approximately 50 kg, 116 specimens) compared to the Catahoula
Formation sample (122 kg, 373 specimens). Two signicant dierences are apparent between these
otolith assemblages. Firstly, only 6.9% of the Glendon Limestone Member assemblage consisted of
Sciaenidae, whereas 96% of the Catahoula Formation otolith sample is sciaenids. Secondly, 51% of the
Glendon Limestone Member otolith sample consisted of Pleuronectiformes (i.e., Paralichthyidae). The
pleuronectid representative in the Catahoula Formation, which is now placed in the family Cyclopsettidae,
represents only 0.7% of the otolith assemblage we examined.
In summary, the Catahoula Formation otolith assemblage is distinctive and remarkable in that 99.2%
of the total specimens in the otolith assemblage are smaller than 5 mm in length, and 96% of the total
specimens consists of representatives in the family Sciaenidae. These peculiarities are believed to be
directly related to the Catahoula Formation paleoenvironment and are discussed in the next section.
Paleoecology and depositional environment of the fossil deposit
The lithological and fossil evidence suggests that our fossil-bearing stratum was deposited in a subtropical,
very nearshore, high-energy environment. The Jones Branch Catahoula Formation fossil bed we sampled
is an argillaceous quartz sand. Grain size ranges from ne to coarse, and grain shape is variable. Most of
the quartz consists of grains of colorless rock crystal that are sub-angular to very well-rounded (nearly
spherical), but a small abraded, prismatic crystal was recovered. Angular grains of pink rose quartz are
much less common, and glauconite is absent. Well-rounded grains indicate bimodal transport (i.e., tidal
inuence), and the presence of more angular grains and excellently preserved terrestrial mammal teeth
suggest mixing of sediment transported a relatively short distance from the source. Starnes & Phillips
(2016) reported that the basal Catahoula Formation represents deltaic deposits with both brackish water
and terrestrial inuences. Freshwater nely laminated clays preserve beautiful broadleaf and palmetto
leaf fossils, whereas the sandy tidal channel beds contain oyster shell hash with marine and terrestrial
vertebrate remains, and quartz and phosphatic pebbles.
With respect to the vertebrate fossils, the presence of terrestrial/brackish water vertebrates like gars,
trionychid turtles, crocodilians, and terrestrial mammals (i.e., small rodents) indicates very close
proximity to the shoreline and inux of sediment via distributary systems. If extant elasmobranchs
provide a model for the environmental preferences of fossil species, the taxa we identied from the
Catahoula Formation support a very nearshore marine environment. For example, tawny nurse sharks
(Nebrius) are predominantly inshore inhabitants where water depth is between ve and 30 m (Compagno
et al. 2005). Daggernose shark teeth (Carcharhinus acuarius) are the most abundant selachian remains
in our sample, and extant C. oxyrhynchus (Müller & Henle, 1839) prefers turbid waters near river
mouths but can be found to depths of 40 m (Compagno et al. 2005). Stingray teeth tentatively identied
as Hypanus are the most abundant batoid remains we recovered, and extant representatives of this genus
occur at depths of nine to 25 m (Snelson et al. 1988; McEachran & de Carvalho 2002; Farmer 2004;
Aguiar et al. 2009). At least three rhinopristiform rays occur in the Catahoula Formation, including
wedgesh (Rhynchobatus) and sawsh (Pristis and Anoxypristis). Living representatives of the former
taxon are often found in coastal waters to depths of 25 m (Compagno & Last 1999a), and those of the
latter two taxa commonly occur in sub-tropical estuarine habitats (Stevens et al. 2008; Radkhah &
Eagderi 2019). Cownosed rays (Rhinoptera) inhabit a variety of nearshore habitats in water depths up to
26 m (Compagno & Last 1999b).
Previous studies have demonstrated the use of bony sh otoliths as paleoenvironmental indicators. This
has been especially true for younger geologic formations, like the Plio-Pleistocene units in the Gulf
and Atlantic Coastal plains (Stringer & Bell 2018; Stringer & Shannon 2019; Stringer & Hulbert 2020;
Stringer et al. 2020a, 2022b). Unfortunately, the relatively limited number of otolith-based taxa we
recovered from the Catahoula Formation adversely impacts this usefulness, as none of the families are
European Journal of Taxonomy 984: 1–131 (2025)
106
particularly diagnostic of freshwater, brackish, or marine environments (Appendix 3), and only very
general paleoenvironmental settings can be hypothesized based on taxonomic composition. Fortunately,
taxonomic composition of otolith assemblages may not be the only indicator of depositional environment.
Analyses of thousands of otolith specimens from Oligocene formations in Louisiana, Mississippi, and
Alabama (Nolf 2003, 2013; Stringer & Worley 2003; Worley 2004; Stringer et al. 2020c; Ebersole
et al. 2021) have revealed that sagittae of Sciaena? pseudoradians are more commonly found in the
5–10 mm range, but specimens greater than 15 mm in length do occur. Based on growth series of
modern sciaenid otoliths from the Gulf of Mexico, one-year-old Sciaenops ocellatus (Linnaeus, 1766)
can reach up to 28 cm in length but have sagittae measuring approximately 15 mm. Additionally,
sagittae of a one-year-old Pogonias cromis (Linnaeus, 1766) are approximately 10 mm, those of a one-
year-old Micropogonias undulatus (Linnaeus, 1766) are around 10 mm, and otoliths of a one-year-old
Aplodinotus grunniens, an extant freshwater inhabitant in North America, are approximately 5.90 mm
in length (GLS pers. obs., 2024). These values provide some indication of the age of the sciaenid shes
represented in the Catahoula Formation otolith assemblage, which were apparently roughly one-year-
old at the time of death. We note here that extant Leiostomus possesses relatively small otoliths, and one-
to two-year-old L. xanthurus Lacépède, 1802 (approximately 140–220 mm total length) have otoliths
around 6.5 mm in length (Bare 2001; Lombarte et al. 2006).
Of the 134 Sciaena? pseudoradians otoliths in our Catahoula Formation sample, only one specimen
measures 10.27 mm in length (0.74% of the sample), whereas the remaining specimens (99.26% of the
sample) measure 5.0 mm or less. More specically, 24.43% of the otoliths measure less than 2.0 mm,
65.65% range between 2.1 and 3.0 mm, and 9.16% are between 3.1 and 5.0 mm in length. Based on
extant analogs, 99.26% of the Catahoula Formation S.? pseudoradians otoliths represent juveniles, most
likely very young at less than one year old. The restricted size distribution of the S.? pseudoradians
sample is enigmatic and atypical of a shallow marine setting, where older juveniles, subadults, and
adults generally occur. This phenomenon may be explained through the habitat preferences of extant
M. undulatus and L. xanthurus, which are both common in the present-day Gulf of Mexico and could
be considered as analogs for Oligocene S.? pseudoradians. If correct, then the size distribution of the
S.? pseudoradians otoliths is indicative of lower-salinity upper reaches of estuaries as well as shallow
soft-bottomed estuarine creeks and bays (Hales & Van Den Avyle 1989; Barbieri 1993; Barbieri et al.
1994; Bare 2001; Stringer & Shannon 2019).
As noted above, elasmobranchs are euryhaline animals that can be found at variable water depths.
However, most of the taxa are indicative of shallow water, and many are quite common in estuarine
environments. An estuarine paleoenvironment is supported by the abundance and size of the
S.? pseudoradians otoliths and is congruent with the other Catahoula Formation otolith-based taxa.
All the fossil sh taxa we identied, whether based on teeth, scales and spines, or otoliths, occur in
present-day brackish and marine waters (Appendix 3). For example, Lepisosteidae occur in freshwater
and brackish environments, Scombridae are freshwater to marine, whereas Sphyraenidae and Labridae
are brackish to marine taxa, and taxa that are primarily/exclusively marine, like Lophiidae, are rare
components (Froese & Pauly 2023). Although a brackish, estuarine environment is indicated by the
Catahoula Formation shes, this does not preclude proximity to and intrusion of shallow marine waters,
which could also explain the presence of Congridae.
The large percentage of Sciaenidae teeth (70% of the tooth-based sample) is congruent with the high
percentage of otoliths assigned to this family (95% of the total otolith sample), and we found that the
families indicated only by skeletal remains are compatible with the paleoenvironment suggested by the
otoliths. Our proposed paleoenvironment is corroborated by the sedimentological evidence, abundance
of oysters, and the terrestrial and marine mammal species that were documented by Albright et al. (2018).
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
107
Additionally, examination of paleogeographic maps for the Oligocene (Smith et al. 1994; Scotese 2014;
Blakey 2020) also indicates that our determination is feasible (Fig. 1).
The taxonomic composition of the Catahoula Formation sh assemblage, particularly the otolith-based
taxa, provides important climatic data that are presented in Appendix 3. The climatic preferences of the
bony sh families based on skeletal material largely overlaps with those taxa based on otoliths. The data
in Appendix 3 show that the only climatic realm in which all the sh families would be found is tropical,
but the occurrence of representatives of ve families indicates subtropical and even temperate climates.
A likely scenario for the Catahoula Formation climate therefore is tropical to subtropical, perhaps even
warm temperate.
Conclusions
We examined more than 13 500 sh fossils that were recovered from the basal Catahoula Formation at
a site in Wayne County, Mississippi. Forty-nine unequivocal taxa are represented by teeth, jaws, scales,
n spines, and/or otoliths. Twenty-nine elasmobranchs have been identied based on teeth, including a
new species of Hemipristis (H. intermedia) and of Galeocerdo (G. platycuspidatum), two new species
provisionally assigned to Sphyrna (“S.” gracile and “S.” robustum), and a new batoid species tentatively
assigned to Hypanus (H.? heterodontus). The elasmobranch component of the assemblage is dominated
by the daggernose shark, Carcharhinus acuarius, but C. elongatus, H. intermedia sp. nov., Carcharias
cuspidatus, Rhynchobatus cf. pristinus, H.? heterodontus sp. nov., and durophagous myliobatids are
also common. Twenty teleost taxa have been identied based on teeth, jaws, scales, n spines, and
otoliths, and this portion of the sh assemblage is dominated by sciaenids (drums) and to a lesser extent
Sphyraena (barracuda). The rst Oligocene western hemisphere record of Tetraodontidae is based on
several beak fragments.
The sh paleofauna we report herein is indicative of an estuarine environment, which is consistent with
previous lithological analyses indicating deltaic deposition. The Catahoula Formation sh assemblage
is of Chattian (late Oligocene) age based on its stratigraphic occurrence (disconformably) above the
Paynes Hammock Limestone, the latter being no younger than latest Rupelian based on planktonic
foraminifers. The Catahoula Formation fossil horizon that we examined is slightly younger than the Old
Church Formation of Virginia (ca 29 Ma) and the Ashley Formation of South Carolina (ca 28.5 Ma)
and slightly older than or equivalent to the Chandler Bridge Formation of South Carolina (ca 25 Ma).
Generically, and often at the species level, the taxa we identied in the Catahoula Formation occur in
Atlantic Coastal Plain Oligocene units.
Acknowledgments
Our knowledge of the site would not have been possible without the contributions of A. Weller and
R. Rains (Waynesboro, Mississippi, USA), who also assisted with eld work and donated specimens
to MMNS. Numerous other individuals assisted GEP with eld work, processing bulk matrix,
and other technical support, including Z. Weller, L. Weller, A. Weller, K. Irwin (formerly Arkansas
Game and Fish Commission), D. Ehret (formerly Alabama Museum of Natural History, Tuscaloosa,
Alabama), J. Rushing (Mississippi Gem and Mineral Society), L. Ritchie, R. Horn, K. Shannon, and
B. Martin. Additional specimens were donated to MMNS by E. Mooney, J. McCraw, J. Dearman, and
W. Collins. Volunteers G. and S. Kelly assisted DJC with microscopic sorting of Catahoula Formation
matrix. K. Johnson (National Marine Fisheries Service), R. Taylor (formerly Florida Fish and
Wildlife Conservation Commission, Fish and Wildlife Research Institute, St. Petersburg, Florida),
and J. Hendon (Center for Fisheries Research and Development, Gulf Coast Research Laboratory,
University of Southern Mississippi, Ocean Springs) generously provided modern shes and otoliths as
comparative specimens. D. Nolf (Royal Belgian Institute of Natural Sciences, Brussels) also supplied
European Journal of Taxonomy 984: 1–131 (2025)
108
modern and fossil otolith specimens to GLS. The Dauphin Island Sea Lab and Alabama Aquarium at
Dauphin Island, AL are thanked for providing modern comparative specimens to MSC. Additionally,
A.F. Bannikov (Russian Academy of Sciences) graciously provided insight into Oligocene Acanthocybium
specimens. Thorough and critical reviews by W. Schwarzhans (Natural History Museum of Denmark,
Zoological Museum, Copenhagen) and T. Reinecke (Bochum, Germany) improved an earlier version
of this manuscript, and their time and eort are greatly appreciated. Reinecke also provided numerous
photographs of fossil teeth that helped us make more accurate comparisons between the fossil Catahoula
Formation and European taxa. Lastly, we wish to thank the editorial sta of the European Journal of
Taxonomy for their time and eort in bringing this article to print.
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Manuscript received: 30 April 2024
Manuscript accepted: 10 October 2024
Published on: 28 March 2025
Topic editor: Marie-Béatrice Forel
Desk editor: Danny Eibye-Jacobsen
Printed versions of all papers are deposited in the libraries of four of the institutes that are members of the
EJT consortium: Muséum national dʼHistoire naturelle, Paris, France; Meise Botanic Garden, Belgium;
Royal Museum for Central Africa, Tervuren, Belgium; Royal Belgian Institute of Natural Sciences,
Brussels, Belgium. The other members of the consortium are: Natural History Museum of Denmark,
European Journal of Taxonomy 984: 1–131 (2025)
130
Copenhagen, Denmark; Naturalis Biodiversity Center, Leiden, the Netherlands; Museo Nacional de
Ciencias Naturales-CSIC, Madrid, Spain; Leibniz Institute for the Analysis of Biodiversity Change,
Bonn – Hamburg, Germany; National Museum of the Czech Republic, Prague, Czech Republic; The
Steinhardt Museum of Natural History, Tel Aviv, Israël.
Appendices
Appendix 1. Taxonomic listing of Chondrichthyes identied from the Catahoula Formation in Wayne
County, Mississippi. With each taxonomic ranking we provide the numbers of specimens for each type
of remains recovered (i.e., teeth, caudal spines), as well as the percentages of the total chondrichthyan
component that each taxon constitutes.
Catahoul a Formation tax on # teeth # scal es # othe r
total # specime ns
(genus/species)
total # specime ns
(Division, Order, Family)
% el asmobranch assem blage
(genus/species)
% el asmobranch assem blage
(Division, Order, Family)
SELACHII 1995 2002 55.38 55.57
Selachii indet. 770.19
Orectolobiformes 21 0.57
Brachael uridae 10. 02
gen. indet. 110.02
Hemiscylliidae 12 0.33
Chilo scyllium sp. 12 12 0.33
Gingl ymostomatidae 80.22
Nebrius sp. 880.22
Lamniformes 245 6.79
Otodontidae 10.02
(Otodus) Carcharocles sp. 110.02
Carcharii dae 240 6.67
Carcharias cuspidatus 240 240 6.67
Pseudocarchariidae 20.05
aff. Pseudocarcharias sp. 220.05
Alopiidae 20.05
Alop ias sp. 2 2 0.05
Carcharhini formes 1729 48.02
Hemigaleidae 193 5.36
Hemipr istis interm edia sp. nov. 193 193 5.36
Carcharhinidae 1344 37.35
Physogaleus contortus 15 15 0.41
Physogaleus sp. 14 14 0. 38
Rhizoprionodon sp. 36 36 1
Carcharhinus acuarius 986 986 27.42
Carcharhinus elongatus 291 291 8.09
Galeorhinus sp. 2 2 0. 05
Scyliorhinidae 30 0.82
Pachyscyllium distans 11 11 0.3
Pachyscyllium sp. 19 19 0.52
Sphyrnidae 116 3.22
"Sphyrna" gracile gen. et sp. nov. 31 31 0.86
"Sphyrna" robustum sp. nov. 85 85 2.36
Galeocerdonidae 46 1.27
Galeocerdo platycuspidatum sp. nov.
46 46 1.27
BATOMORPHII 1215 1593 42.79 43.23
Batomorphi i inde t. 943 52 1.44
Rhinopristiformes 298 8.27
Rhinidae 246 6.84
Rhynchobatus cf. R. pristinus 246 246 6.84
Pristidae 22 1.43
Prist is sp. 28 12 40 1.16
Anoxypristis sp. 10 10 0.27
Myliobatiformes 1243 33.52
gen. indet. (durophagous) 326 326 9.06
Dasyatid ae 582 16.18
Hypanus? heterodontus sp. nov. 578 578 16.07
gen. et sp. indet. 31 4 0.11
Myliobatidae 222 6.16
"Mylio batis " sp. 170 1171 4.75
"Aetomylaeus " sp. 49 251 1.41
Rhinopteridae 110 3.05
"Rhinoptera " sp. 110 110 3.05
Mobulidae 30.07
Plinth icus sp. 1 1 0. 02
Paramobula fragilis 2 2 0.05
42.79
Euselachii indet. 10 9
total = 3210 total = 3595 total = 98.17% t otal = 98. 8%
CICIMURRI D.J. et al., Chattian shes from eastern Mississippi, USA
131
Appendix 2. Taxonomic listing of Teleostei identied from the Catahoula Formation in Wayne County,
Mississippi. With each taxonomic ranking we provide the numbers of specimens for each type of
remains recovered (i.e., teeth, otoliths), as well as the percentages of the total bony sh component that
each taxon constitutes.
Appendix 3. Habitat distribution and general climatic ranges of the families of otolith-based bony shes
from the Catahoula Formation at the Jones Branch locality. Key to superscripts: 1 = rarely freshwater or
brackish; 2 = primarily marine with some brackish; 3 = primarily brackish and marine coastal waters;
4 = chiey marine and rarely freshwater; 5 = mainly tropical to warm temperate; 6 = primarily marine
with a few brackish.
Osteichth yan Famil y
Freshwater Brackish Marine Tropical Subtropical Temperate Arctic
Albulidae
1
Congridae
2
Cyclopsettidae
3
Haemul idae
4
Sciaenidae
5
Sparidae
6
Environmental Distribution
Climatic Range
Catahoula F ormation taxo n # teeth # sca les # jaw elements # otoliths # othe r
total # specimens
(genus/species)
total # specimens
(Division, Order, Family)
% bony fish assemblage
(genus/species)
% bony fish assemblage
(Division, Order, Family)
GINGLYMOD I 173 1.96
Lepisosteiformes 173 1.96
Lepisosteidae 173 1.96
gen. indet. 109 64 173 1.96
TELEOSTEOMORPHA 8628 97. 18
Albuliformes 63 0.71
Albulidae 63 0.71
gen. indet. 48 6 9 63 0.71
Anguilliformes 30.04
Congridae 30.03
Protanago nonsector 2 2 0.02
gen. indet. 1 1 0.01
Siluriformes 80.09
gen. indet. 8 (fin spine) 80.09
Istiophoriformes 609 6.91
Sphyraenidae 609 6.91
Sphyraena sp. 609 609 6.91
Pleruonectiformes 30.03
Cyclopsetti dae 30.03
Syacium sp. 330.03
Scombrif ormes 178 2.01
Scombridae 178 2.01
Acanthocybium sp. 3 3 0.03
Scomberomorus sp. 175 175 1.98
Labriforme s 19 0.21
Labridae 19 0. 21
gen. indet. 12 7 (too th mass) 19 0. 21
Percif ormes 114 1.17
Haemuli dae 10.01
Allomorone sp. 1 1 0.01
Lutjanidae 113 1.28
gen. indet. 112 1113 1.28
Acanthuriformes 6171 70. 1
Sciaen idae 6171 70.1
Aplodinotus distortus 19 19 0.21
Aplodinotus gemma 46 46 0.52
Sciaena? pseudoradians 134 134 1.52
Sciaena? radians 3 3 0.03
gen. indet. 5761 16 192 5969 67.82
Spariforme s 1225 13.88
Sparidae 1225 13. 88
Diplodus sp. 183 183 2.07
Sparus? cf . elegantulus 1 1 0.01
gen. indet. 1041 1041 11.8
Lophiiformes 229 2.6
Lophiidae 229 2.6
gen. indet. 229 229 2.6
Tetraodontiforme s 60.06
Tetraodontidae 60.06
gen. indet. 6 6 0.06
Actinopterygii
gen. indet. 843 17 276 (mis c.)
total = 8801 total = 8801 total = 99.88% total = 99.14%
