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Lucas, S. G., DiMichele, W. A. and Allen, B. D., eds., 2021, Kinney Brick Quarry Lagerstätte. New Mexico Museum of Natural History and Science Bulletin 84.
CTENACANTHIFORM SHARKS FROM THE LATE PENNSYLVANIAN (MISSOURIAN)
TINAJAS MEMBER OF THE ATRASADO FORMATION, CENTRAL NEW MEXICO
JOHN-PAUL M. HODNETT, 1, 2, 3* EILEEN D. GROGAN, 2 RICHARD LUND, 2 SPENCER G. LUCAS3, TOM SUAZO, 4
DAVID K. ELLIOTT 5 and JESSE PRUITT 6
1Maryland-National Capital Parks and Planning Commission, Natural and Historical Resources Division, Archaeology Program, 8204 McClure
Road, Upper Marlboro, MD 20772, jp.hodnett@pgparks.com; 2Department of Biology, St. Joseph’s University, 5600 City Ave, Philadelphia,
PA 19131, egrogan@sju.edu, rdicklund3@gmail.com; 3New Mexico Museum of Natural History and Science, 1801 Mountain Rd NW,
Albuquerque, NM 87104, spencer.lucas@state.nm.us; 424 Chamisa Loop, Edgewood NM, 87015; 5Geologic Program, SESE, Northern Arizona
University, Flagsta, AZ 8600, david.elliott@nau.edu; 6Idaho Virtualization Lab, 921 S 8th Ave, Stop 8096, Pocatello, ID 83209,
pruijess@isu.edu
Abstract—Two species of ctenacanthiform sharks are presently recognized at the Late Pennsylvanian
(Missiourian) Kinney Brick Quarry Lagerstätte in the Manzanita Mountains east of Albuquerque New
Mexico. A few isolated teeth of Glikmanius occidentalis have been collected from the quarry over a
number of years and represent a large though rare ctenacanth in the Kinney Brick Quarry vertebrate
assemblage. Dracopristis homanorum gen et sp. nov is a new Pennsylvanian ctenacanth taxon and
represents the most complete ctenacanth found in North America. The morphology of Dracopristis
homanorum suggests it specialized in benthic environmental conditions as a slow moving ambush
predator in the shallow estuary/lagoon of Kinney Brick Quarry locality. Morphological data from
Dracopristis homanorum gen et sp. nov. and a review of the more complete ctenacanth taxa provided
new information for cladistics analysis suggesting that Dracopristis homanorum gen et sp. nov and
other ctenacanths form a monophyletic group with a close sister relationship to Euselachii and were
not members of the Cladodontomorphi.
INTRODUCTION
What is a Ctenacanth?
Are ctenacanths a natural group of Paleozoic sharks? The
idea of a ctenacanth group (e.g., Dean, 1909; Glikman, 1964)
and its relationship to others within the Class Chondrichthyes
is still debated in part due to the restricted nature of the
endoskeletal remains recovered to date. The rst description of
a “ctenacanth” fossil was that of the Mississippian Ctenacanthus
major by Agassiz (1837), based on a poorly preserved isolated
spine described as triangular in cross-section and having
longitudinal rows of small denticles. Subsequently, many other
Paleozoic (Upper Devonian to Permian) dorsal n spines that had
near identical to vague similarities to Agassiz’s holotype were
placed within this genus (Maisey, 1981, 1982, 1984). Traquair
(1884) described the rst complete, though poorly preserved
specimen with articulated ctenacanth-like spines from the lower
Carboniferous Glencarthom-Eskdale fossil beds of Scotland,
which he designated “Ctenacanthus” costellatus. The condition
of the holotype (BMNH P 5900) limited Traquair (1884) to note
that “Ct.” costellatus was a moderately elongate shark, with
a blunt snout, having a heterocercal tail, skin covered with a
shagreen of placoid denticles, two dorsal ns that each bore a
tall spine with rows of longitudinal denticles, and cladodont
teeth. With additional material at hand, Moy-Thomas (1936)
expanded the diagnosis of “Ct.” costellatus to include a tribasal
pectoral n articulation, unfused pelvic plates, and the presence
of an anal n. Although “Ct.” costellatus became the model of
Ctenacanthus (Moy-Thomas, 1936), Woodward (1889), Maisey
(1981, 1982) and Ginter et al. (2010) questioned the placement
of this taxon within Ctenacanthus, suggesting placement within
another genus due to the ornamentation of the dorsal spine
being signicantly dierent from the type specimen and from
the morphology of the teeth. “Ct.” costellatus was treated as
a ctenacanth but as a taxon separate from Ctenacanthus sensu
stricto (Ginter et al., 2010; Hodnett et al., 2012; Ivanov and
Lebedev, 2014). Recently, Ginter and Skompski (2019) erected
a new genus, Glencartius, for the Glencartholm specimens.
All other edoskeletal remains currently attributed to the genus
Ctenacanthus derive from the Upper Devonian (Fammenian)
Cleveland Shale of Ohio, U.S.A. The rst denitive description
was made by Dean (1909) of an articulated anterior portion
of a single individual (AMNH 189) with a crushed cranium,
articulated pectoral skeleton, and the impression of an anterior
dorsal. He referred this Cleveland Shale material to Ctenacanthus
clarki (Newberry, 1889) based on features of the dorsal n spine.
Maisey (1981) later validated the Ctenacanthus designation but
determined it was more appropriately synomymized with Ct.
compressus (Newberry, 1878). Since this initial description,
additional articulated specimens of Ctenacanthus have been
collected, though only briey described (Williams, 2001).
Ginter (2010) later would refer many of the Cleveland Shale
specimens to Ct. concinnus (Newberry, 1875).
Beyond Ctenacanthus
Dean (1909, Part I) established the Ctenacanthidae as one of
four “cladoselachian” families, with this family distinguished by
two dorsal ns with spines and by certain features of the pectoral
n design. Glikman (1964a), citing tooth, n and spine features,
would later extract Ctenacanthidae (comprised of Ctenacanthus
and Goodrichthys) from the cladoselachians, placing them
in an Order Ctenacantida and Superorder Ctenacanthi, as
elasmobranchs with supposed “osteodont” teeth. Zangerl (1981)
then placed the Ctenacanthidae (Ctenacanthus, Goodrichthys,
and, tentatively, Cratoselache) within a Superfamily
Ctenacanthoidea in the Euselachii Hay, 1902. Ginter et al.
(2010) formalized Glikman’s (1964b) Ctenacantida as the
Ctenacanthiformes. The latter constituted one of four orders
within the Superorder Cladodontomorphi and was removed
from a more narrowly dened cohort Euselachii.
Endoskeletal material currently attributed to the
Ctenacanthiformes includes Goodrichthys eskdalensis Moy-
Thomas, 1936, Cladodoides wildungensis Maisey, 2005,
Heslerodus divergens (formerly Phoebodus heslerorum
Williams, 1985; Ginter, 2002; Maisey, 2012), “Tamiobatis
vetustus” (Williams, 1998), Cladodus elegans (Ginter and
Maisey, 2007), and a partial associated skeleton of a new unnamed
Upper Mississippian Bear Gulch taxon (Hodnett et al., 2016).
392
Sphenacanthus and Bandringa of Zangerl’s “Ctenacanthoidea”
(1981) are no longer considered to be ctenacanths (Maisey,
1982; Ginter et al., 2010; Sallan and Coates, 2014).
Here, we describe the ctenacanthiform sharks from the Late
Pennsylvanian (Missourian) Tinajas Member of the Atrasado
Formation at the Kinney Brick Quarry in central New Mexico
USA, which include Glikmanius occidentalis and a new taxon
based on a complete specimen. The new taxon reveals a
Tamiobatis-like neurocranium, Ctenacanthus-like dorsal spines,
and Heslerodus-like dentition. This new taxon and specimen is
the keystone to a new analysis to better understand “what is a
ctenacanth.” Furthermore, the Kinney Brick Quarry ctenacanths
add data to the discussion on the diversity of Ctenacanthiformes
during the late Paleozoic.
GEOLOGIC SETTING
The Kinney Brick Quarry (KBQ) is an active, privately
owned commercial quarry for clay that is used in the production
of masonry bricks (Fig. 1B). The Kinney Brick Quarry is in the
Manzanita Mountains east of Albuquerque New Mexico and is
well known as a Konservat Lagerstätte that preserves the soft
tissues of plants and animals, including a fairly diverse sh
assemblage (Zidek, 1992a; Lucas et al, 2011; Hodnett and Lucas,
2015). Fossil sh were rst reported from the KBQ by Zidek
(1975) based on collections made at the KBQ in the 1960’s by
David Dunkle and Sergius Mamay. At present, approximately
27 sh taxa have been collected from the KBQ, which include
an acanthodian, 8 chondrichthyans, 14 actinopterygians, and 3
sarcopterygians (Hodnett and Lucas, 2015).
The Tinajas Member of the Atrasado Formation at the KBQ
is 56 m thick, with the majority of the best preserved fossil-
producing beds coming from a 3-m-thick section, divided into
seven units, near the quarry oor (Fig. 1C-D). The depositional
setting of this section represents a regressive embayment or
estuary fed by a river delta (Feldman et al., 1992; Lorenz et al.,
1992). The bottom of this 3 m thick section is a blocky black
micrite (unit 1) with only a few isolated sh remains reported
(Williams and Lucas, 2013). Above the black micrite is a black-
banded and slightly ssile calcareous shale (unit 2) from which
a few articulated sh have been collected (Williams and Lucas,
2013). Unit 3 is a ssile, banded calcareous shale ranging from
black with orange bands near the bottom that grades to a more
orange-dominated shale at the top where most of the articulated
sh have been collected (Williams and Lucas, 2013). Between
units 3 and 4 is a distinct, thin, laminated gray-yellow shale that
has produced a number of articulated, well-preserved sh. Units
4-7 also contain articulated and isolated sh remains, though
they are not as common as in unit 3, and these upper units consist
of gray, soft, calcareous shale with very well preserved plant
fossils (DiMichelle et al., 2013; Williams and Lucas, 2013). The
Glikmanius occidentalis teeth presented here were collected
from units 3 and 4, while the new taxon (described below) was
collected from the thin, laminated, gray-yellow shale between
units 3 and 4 (Fig. 1D). Lucas et al. (2011) determined the age
of the Kinney Brick Quarry assemblage to be of Missourian
(Kasimovian) age based on its stratigraphic position and the
biostratigraphy of fusulinids and conodonts.
METHODS
Imaging
Computed tomography of the head jacket of NMMNH
P-68537 was undertaken at Rust Presbyterian Medical Center
in Rio Rancho, New Mexico. The computed tomography was
conducted using a Siemens 64 slice Somatom Denition AS
at 0.5 mm spatial resolution. Three dimensional segmentation
models were rendered with ITK-SNAP (Yushkevich et al.,
2006). Surface rendering of NMMNH P-68537 was captured at a
maximum point-to-point resolution of 0.01 mm into PolyWorks
Align. The resulting point cloud was aligned in PolyWorks
Align module, surfaced with Merge module, and exported as
an obj le from the Edit module. The raw obj le was edited
in Geomagic Wrap 2015 and exported in four sections to be
imported into ZBrush 4R7 P3.
The nal model is 56.151 million points, 112.242 million
polygons. The render was done in Luxion Keyshot using three
point lighting and physically based rendering. Scanning electron
microscopy was conducted using a JSM-6480LV scanning
electron microscope at the Electron Microanalysis Core Facility
at Northern Arizona University. Photographs were taken with
a Nikon CoolPix S3300 or APPLE IPhone 5S at 300 dpi and
edited with Adobe Photoshop CC 2015. Additional gures
were rendered with Adobe Illustrator CC 2015 from photo or
computed tomographic overlays.
Cladistic Analysis
Analysis was performed with a matrix modied from
Grogan and Lund (2008). It consists of 144 characters (0-
143) and uses 49 to 56 taxa that include six outgroups, a
placoderm (Coccosteus decipiens), two sarcopterygians (the
coelacanth Hadronector donbairdi and onychodont, Onychodus
jandemarrai), an actinopterygian (Kalops monophyrs), and
the acanthodian Ptomacanthus anglicus. Cladistic analysis
was performed using TNT version 1.1 (Golobo et al., 2008).
The rst analysis of 49 taxa only includes Ctenacanthus and
Dracopristis, and the second analysis of 56 taxa includes
seven additional taxa (Cladodus, Goodrichthyes, Cladodoides,
Heslerodus, CMNH 9280, and CM 46006), which have been
proposed to be within the Ctenacanthiformes.
Abbreviations
Institutional Abbreviations—AMNH, American Museum
of Natural History, New York; BGS, British Geological Survey,
Keyworth, Nottingham; BMNH, British Museum of Natural
History, London; CM, Carnegie Museum of Natural History,
Pittsburgh; CMNH, Cleveland Museum of Natural History,
Cleveland; FMNH PF, Field Museum of Natural History,
Chicago. NMMNH P, New Mexico Museum of Natural
History and Science, Albuquerque; NMS, National Museums
of Scotland, Edinburgh; USNM, National Museum of Natural
History, Washington D.C.
Anatomical Abbreviations— ADP, Anterodorsal process
of the palatoquadrate; ADFS, anterior dorsal n and spine; AF,
anal n plate; BB, basipterygium; BD, basidorsal elements;
BMD, buccal membrane denticles; CB, ceratobranchials;
CF. caudal n; CH, ceratohyal; CT, ceratotrichia; dOC,
dorsal otic crest; DR, distal radials; EB, epibranchials; EnLF,
endolymphatic fossa; EtP, ethmoid process; FT, functional
teeth; GA, gill arches; GR. gill rays; HA, hemal arches; HH,
hypohyal; HY, hyomandibula; LDC, lateral dorsal crest; LPCF,
left pectoral n; LPP, left pelvic plate; MC, Meckel’s cartilage;
MS, mesopterygium; MT, metapterygium; NA, neural arches;
NC?, nasal capsule?; NC, neurocranium; OCC, occipital
FIGURE 1. (facing page) Paleogeographic location, stratigraphic and geological timescale position, and photo of Kinney Brick
Quarry (KBQ). A, Paleogeographic map of the Four Corners states (Arizona, Utah, New Mexico, and Colorado) during the
Missourian Late Pennsylvanian and the approximate position of KBQ (image modied from Hodnett and Lucas, 2017); B, Photo
of KBQ, May 21st, 2013, the day the holotype of Dracopristis homanorum was discovered; C, Stratigraphic diagram of the
Pennsylvanian section of central New Mexico, star indicates position of Tinajas Member of the Atrasado Formation; D, Stratigraphy
of KBQ and the approximate position of recovery of Glikmanius occidentalis teeth (tooth silhouette) and the NMMNH P-68537,
holotype of Dracopristis homanorum.
393
394
cotylus; OOF, occipital otic ssure; PB, pharyngobranchials;
PFT, post-functional teeth; PO, postorbital process; PP,
pelvic girdle; PQ, palatoquadrate; PR, proximal radials; PrFn,
precerebral fontanelle; PT, propterygium; RAP, retroarticular
process; RPCF, right pectoral n; RPLF, right pelvic n;
SC, scapulorcoracoid; SN, supraneural elements; UAT , upper
anterior teeth; VMD, ventral mandibular ridge; 2C, secondary
cartilage.
SYSTEMATIC PALEONTOLOGY
Class CHONDRICHTHYES Huxley, 1880
Subclass ELASMOBRANCHII Bonaparte, 1838
Order CTENACANTHIFORMES Glikman, 1964
Revised Diagnosis—Elasmobranch chondrichthyans
having neurocrania with anteroposteriorly deep and
mediolaterally wide precerebral fontanelle, dorsal otic ridge
originating anterior to the posterior margin of the postorbital
process, and laterally projecting otic process; palatoquadrates
with a square-shaped anterodorsal process on the otic process and
a well-developed dorsal ridge originating from the anterodorsal
otic process to the quadratic process; Meckel’s cartilage with
a ventrolateral ridge originating from the articular cotylus and
retroarticular process and extending nearly two thirds the length
of the jaw; and basolabial depression present on dentition,
basolabial and orolingual projections of dentition wider than the
median cusp, and on a well-developed lingually extended root
base.
GLIKMANIUS OCCIDENTALIS Leidy, 1859
Figure 2
Referred Specimens—CM 47847, isolated tooth;
NMMNH P-32923, tooth in matrix; NMMNH P-42304, isolated
tooth; NMMNH P-67714, tooth in matrix; USNM 187135, tooth
in matrix.
Description—Five isolated large teeth with tooth bases
ranging between 15 and 20 mm long mesiodistally (Fig. 2). The
median cusp is tall, narrow and slightly inclined lingually. The
lateral cusps are narrow, approximately half the height of the
median cusp, and are angled away from the intermediate cusp
mesiodistally. The intermediate cusp is approximately a quarter
of the height of the median cusp and is positioned forward of
the median and lateral cusps. All cusps are ornamented with
coarse cristae on the labial and lingual surfaces. The basolabial
depression is well developed and relatively deep. The tooth base
is trapezoidal with rounded edges and the labial mesiodistal
margins recurving inward. The orolingual ridge and basolabial
projections form two separate elliptical buttons. The orolingual
buttons are positioned on the lingual margin of the base. The
basolabial projections are positioned in line with the intermediate
cusps.
Remarks—Glikmanius has an extensive fossil record and
geographic distribution, with its earliest appearance during the
latest Mississippian (Serpukhovian) from isolated teeth identied
as Glikmanius sp. from North America and Russia (Ginter et
al., 2005). Three formally named species, G. occidentalis, G.
myachovensis, and G. culmenis, are recognized. G. occidentalis
is the largest of the three species, which is characterized by its
robust proportions, the oral lingual buttons positioned towards
the lingual margin of the tooth base, and the intermediate
cusps positioned anterior to the median and lateral cusps. G.
occidentalis is known through the Pennsylvanian globally, with
the youngest records from the middle Permian of Japan and
North America (Ginter et al., 2005, 2010; Hodnett et al., 2012).
Glikmanius myachovensis is a small and gracile form
characterized by proportionally slender cusps, the presence of
secondary intermediate cusps, the intermediate cusp in line with
the median and lateral cusps, the orolingual buttons positioned
away from the lingual margin of the tooth base, and the lingual
margin of the base having a downward incline. Previously
thought to be restricted to the Late Pennsylvanian (Ginter et al.,
2005), G. myachovensis is now known to have extended into the
middle Permian of Oman and North America (Hodnett et al.,
2012; Koot et al., 2013). G. myachovensis is the most common
ctenacanth from the Khu Formation of Oman (Koot et al.,
2013) and the second most common ctenacanth in the Kaibab
Formation of Arizona (Hodnett et al., 2012). Koot et al. (2013)
recently described a third taxon, G. culmenis, from the middle
Permian Khu Formation of Oman. G. culmenis is a small tooth
taxon distinguished by its reduced intermediate and lateral
cusp size, weakly developed orolingual buttons, and a shallow
basolabial depression.
At present, only isolated teeth represent Glikmanius
occidentalis in the Atrasado Formation, which presently is the
largest chondrichthyan at Kinney Quarry. These teeth were
previously referred as Cladodus sp. and Symmorium reniforme,
respectively (Zidek, 1975 and 1992; Williams and Lucas, 2013)
until reclassied and reviewed by Ginter et al. (2005) and
Hodnett and Lucas (2015).
DRACOPRISTIS gen. nov.
urn:lsid:zoobank.org:act:E25CF27E-C1E0-4922-B9AF-
F366EC4FA473
Diagnosis—As for species by monotypy
Etymology—From Latin “draco,” for dragon and Latin
“pristis” for shark; in reference to the coarse facial dermal
denticles, retained labial teeth, and large dorsal spines that give
this shark a dragon-like appearance.
DRACOPRISTIS HOFFMANORUM, sp. nov.
urn:lsid:zoobank.org:act:31E6E7DB-4CB4-4AF7-AD87-
56DA69767B22
Diagnosis—A medium-size ctenacanthiform shark with
an estimated body length of 206 cm. Body form craniocaudally
elongated and dorsoventrally narrow. Dentition is cladodont
with all cusps triangular in shape with v-shaped cristae, median
cusp relatively tall, lateral cusps are half the height of the median
cusp, a single intermediate cusps positioned just forward of the
median cusp, moderately developed basolabial depression, and
orolingual and basolabial projections are two separate elliptical
buttons. Neurocranium mediolaterally broad, postorbital process
anteroposteriorly broad, posterior margin of the dorsal otic ridge
is chisel shaped, a laterally projecting process present on lateral
otic ridge, and no median crest on occipital. Palatoquadrates
with a moderately developed anterodorsal process on otic
process, otic process dorsoventrally deep, and palatine ramus
short. Meckel’s cartilage with pointed, moderately developed
retroarticular process, and relatively dorsoventrally deep
and anteroposteriorly short dental ramus. Hyomandibula
dorsoventrally expanded anteriorly. Five branchial arches
present, the largest anterior and the remainder decreasing in
size posteriorly. Pharyngobranchials thin, blade-like laminae
that taper posteriorly with anterior y-shaped articulations. Each
dorsal n spine supported with large basal plates and n radials.
Dorsal spines ornamented with lateral, longitudinal costae
bearing elliptical to rounded denticles and a single smooth
anterior costa with small transverse ridges. First dorsal spine is
57 cm, 27% of the total body length and recurving posteriorly
over body. First and second dorsal n ceratotrichia connected to
dorsal spines. Anal n present, internally supported by a single
fused plate. Caudal n internally heterocercal, of the plesodic
style. Hypochordal lobe principally supported by proximal and
distal radials, the latter, associated with proximal radials 2-8,
taper distally to a point, grade in size from the rst to the third
distal, which is largest in size and recurved posterocaudally.
Subsequent distal radials 4-6 decline in size thereafter. Proximal
caudal radials articulate with haemal arches and spines.
395
FIGURE 2. Teeth of Glikmanius occidentalis from KBQ. A-E, CM 4784, A, labial, B, lingual, C, mesial, D, oral, E, aboral; F-H,
NMMNH P-42304, F, labial, G, oral, H, aboral; I, NMMNH P-67714 in oral view; J, NMMNH P-32923 in labial view; K, USNM
187135 in labial view. Scale bars equal 1 cm.
Epichordal lobe at a near right angle. Scapulocoracoids form
an anteriorly directed narrow process. Scapular blade margin
expanded posteriorly from dorsal apex to caudally rounded
margin before narrowing and expanding into a concave ridge.
More ventrally, this narrows to a posteriorly directed glenoid
process. Pectoral n with tribasal articulation and aplesodic
endoskeletal n. A secondary trapezoidal cartilage present in
pectoral n, articulating on ventral margin of mesopterygium
and anterior margin of metapterygium. Pelvic girdle triangular
and bearing series of proximal n radials; metapterygium or
metapterygial axis not evident.
Etymology—Species name to honor Ralph and Jeanette
Homan, the owners of the KBQ, for their support of the
research conducted at the KBQ.
Holotype—NMMNH P-68537, nearly complete articulated
adult female endoskeleton with in situ dermal denticles, and soft
tissue impressions.
Locality and Horizon—Tinajas Member, Atrasado
Formation, Upper Pennsylvanian (Missourian); Kinney Brick
Quarry, Bernalillo County, New Mexico.
Body—The body of this chondrichthyan is preserved
with its right side exposed and the cranium and gill arches
dorsoventrally compressed (Fig. 3). It has an approximate body
length of 206 cm measured from the anterior end of the ethmoid
region of the cranium to the distal end of the dorsal caudal lobe
of the tail. All the endoskeletal elements are articulated or nearly
articulated in life position. The forms of the body, pectoral,
pelvic, anal, caudal and both dorsal ns are preserved from
the placement of the dermal denticles or impressions of the n
ceratotrichia.
Neurocranium—The neurocranium is preserved obliquely
dorsoventrally with the dorsal and part of the left lateral surfaces
of the neurocranium exposed (Fig. 4). The neurocranium is 245
mm long from the anterior border of the preorbital process to the
posterior margin of the occipital condyle; and the greatest width
of the neurocranium is 170 mm across the postorbital processes.
The opening for the precerebal fontanelle is deeply incised
between the preorbital process in a mediolaterally wide V-shape.
A mediolaterally broad internasal plate is present. There are
eight openings for the supercial ophthalmic complex seen on
the right side of the supraorbital shelf. These nerve openings
originate just posterior to the opening of the notch for the
supercial ophthalmic ramus and terminate near the transverse
midline of the postorbital process. The mediolateral width
between the supraorbital shelves is broad. No articular facet for
the palatoquadrate can be seen on the surface of the specimen,
but the CT scans show connection between the two elements.
The otic region of the neurocranium is anteroposteriorly elongate
in proportion to the ethmo-orbital region. The dorsal otic ridge
originates anterior to the posterior margin of the postorbital
process and extends over to just anterior of the otic-occipital
ssure with a chisel-like posterior margin. The endolymphatic
fossa is long and narrow. A pointed process projects laterally
from the lateral otic ridge. This process corresponds to a small
facet on the lateral otic ridge in CMNH 9280, which forms an
articulation for the palatoquadrate (Williams, 1998). A lateral
396
FIGURE 3. NMMNH P-68537, the holotype of Dracopristis homanorum. A, Photograph of the head, body, and tail blocks
reassembled; B, Surface scan rendering of the head, body, and tail blocks reassembled; C, Line drawing overlay of the surface scans
showing the skeletal features and body outline as preserved in the specimen. Scale bars equal 1 meter.
projecting otic process is present. The articular facet for the
palatoquadrate is square shaped, and an elliptical opening is
present near the medial origin of the otic process. The left otic
process is preserved in articulation with the left palatoquadrate.
An otico-occipital ssure is present. A median occipital crest
is absent. The occipital condyles are mediolaterally wide and
dorsoventrally shallow.
Due to the dorsoventral compression of the cranium, most
of the internal features from CT scans are not clear or easily
discernable. The canal for the supercial ophthalmic complex
is seen in the CT scans, and it is fairly wide mediolaterally,
suggesting it contained a large nerve. The opening for the
jugular canal in the postorbital process is mediolaterally wide
and extends through the postorbital process. The mandibular
ramus of the trigeminal nerve canal extends longitudinally
through the postorbital process, exiting laterally from the post
orbital process. The canals for the vagus and glossopharyngeal
nerves are clearly seen in the CT scans and were positioned
posterior to the otic process and anterior to the occipital condyle.
Dentition and Squamation—NMMNH P-68537 is
preserved with in situ placement of the dentition, buccal
membrane denticles, and dermal denticles (Fig. 5). There is
evidence of tooth retention in densely conned rows around the
outside of the mandibular arches, serially continuous with the
families of developing and functional teeth. The outer retained
teeth are typically smaller than the functional tooth families. The
397
FIGURE 4. The head block of NMMNH P-68537, Dracopristis homanorum. A-B, Dorsal view, A, Photograph of cranial elements
as exposed on the surface, B, Line drawing created from surface photography and computed tomography modeling; C-D, Ventral
view, C, Volumetric model made from computed tomography scans, D, Line drawing. Scale bars equal 10 cm.
best exposed dentition comes from the right Meckel’s cartilage,
which shows 12 tooth families lingually. The dentition of the
palatoquadrates cannot be seen from the surface of the specimen,
however, computed tomography indicates that 12 tooth families
are present. Two rows of upper anterior teeth are present that are
supported by the ethmoid region
Teeth are of a homodont arrangement with the family of
largest teeth (approximately 16 mm wide mesiodistally) anteriorly
positioned. The sizes of the teeth decrease posteriorly with the
smallest tooth approximately 7.5 mm wide mesiodistally. The
crown consists of a tall, triangular and somewhat mesiodistally
wide median cusp. The lateral cusps are approximately half
the height of the median cusp, slightly splay mesiodistally, and
are triangular in shape. The triangular intermediate cusps are
approximately three fourths the height of the lateral cusps and
positioned just labial to the median cusp. The lingual margins
of the cusps are strongly convex, and the labial margins are
only slightly attened. Coarse, well dened v-shaped cristae
ornament the labial surfaces of the crowns, which form multiple,
additional, sharp carina-like edges. Additional labial cristae
extend from the basolabial margin of the tooth base to just above
the origin of the crown, some of which show bifurcation. Lingual
cristae originate just labial of the orolingual projections and
extend to the crown apex, some forming v-like patterns similar
to the labial cristae. The basolabial depression is shallowly
developed and u-shaped. The tooth base is reniforme in shape,
with a attened labial margin and convex lingual margin. The
lingual torus is labiolingually deep and mesiodistally wide. The
basolabial and orolingual projections consist of two elliptical,
attened pads. The orolingual projections are widely spaced
and positioned towards the mesiodistal margins of the base,
just forward of the lingual rim. The basolabial projections are
positioned just underneath and between the intermediate and
lateral cusps.
A partial juvenile tooth was collected among the dermal
denticles extracted at the rostrum (Fig. 5D-H). This tooth
fragment shows a well-developed basolabial and orolingual
projection and well preserved lateral and intermediate cusps.
The cusps of this tooth dier from the functional tooth families
of the mandibular arches in being more conical in shape but
398
FIGURE 5. Dentition of Dracopristis homanorum. A-C, Exposed teeth from the right Meckel’s cartilage, A, labial viewed tooth
from the third tooth family, B, Labial viewed tooth from the fourth tooth family (note following replacement tooth), oral view tooth
from the second tooth family; D-H Juvenile retained tooth collected from dermal denticle samples from the nasal region, D, labial,
E, lingual, F, mesial?, G, aboral, H, oral; I-N teeth of Pennsylvanian Sharks (not to scale), I-J, Dracopristis homanorum, I, labial,
J, oral, K-L, Heslerodus, K, labial, L, oral, M-N, Glikmanius, M, labial, N, oral. Scale bars for A-C equal 1 cm; scale bars for D-H
equal 500 µm.
retain the coarse, well-dened, v-shaped cristae. The tooth base
overall is also thicker dorsoventrally in this specimen.
Numerous buccal membrane denticles are present in the
region between the oral cavity and the gill arches just anterior
of the scapularcorocoid. The buccal membrane denticles range
between 2.5 mm to 5 mm in diameter and can be seen visually
along the lingual margin of the Meckel’s cartilage just below
the functional tooth families and the inner surfaces of the gill
arches. Computed tomography scans show buccal membrane
denticles along the ethmoid region of the neurocranium as well.
Multiple samples of dermal denticles were collected from
the anterior nasal region of the cranium, anterior to the anterior
dorsal n, the shoulder girdle, the dorsal region between the
anterior and posterior dorsal ns, and the ventral region just
posterior of the pelvic n (Fig. 6). Denticles extracted from
around the rostrum of the cranium consist primarily of small
(0.5 mm to 1 mm in diameter), densely constructed, pentagonal
or hexagonal shaped nodules with rugose stellate ornamentation.
This rugose stellate ornamentation has a central point from
which the ridges radiate to the outer margin of the denticle.
These ridges in turn have additional ne transverse striations.
Small vascular canals perforate the outer margins just below the
crown of the denticle. Additional nodule-like denticles from the
cranium show multiple small peaks with striations and cristae.
Posterior to the cranium, the primary body dermal denticles
are thin and leaf-like in shape with multiple longitudinal ridges
running the length of the denticle crown and have jagged
posterior margins. Articulated denticle samples demonstrate
that these crowns t tightly together but do not overlap. The
crowns of these denticles are posteriorly directed. The bases of
these denticles are thin and ovate in shape with multiple nutrient
foraminae positioned between the denticle crown and the outer
margin of the denticle base. Some of the aboral surfaces of the
crown and base shown thin ridges as well. The dorsoventral
heights and anteroposterior lengths of these dermal denticles are
variable based on the position on the body. Denticles collected
near the anterior dorsal n tend to be dorsoventrally compressed
and anteroposteriorly elongate, whereas denticles collected just
posterior of the pelvic ns are more dorsoventrally elongate and
anteroposteriorly short.
Mandibular and Hyoid arches—The left elements of
the mandibular and hyoid arches are dorsoventrally preserved
in articulation with the neurocranium (Fig. 4). The right
palatoquadrate, Meckel’s cartilage, and ceratohyal are exposed
medially with the right hyomandibula exposed laterally, lying
on the right ceratohyal. These elements are not articulated to
the neurocranium and have moved just anterior to the rostrum
of the shark. However, the right mandibular and hyoid arches
are articulated with the left mandibular and hyoid arches by the
distal ends of the hypohyals.
The palatoquadrate is 26 cm long with an expanded
posterior otic process that is 14 cm wide, measured from the
otic articular process to the quadrate condyle; and 10.2 cm
deep, measured from the dorsal margin of the otic process to the
ventral margin. The anterior ventral margin of the palatoquadrate
is slightly convex, which then transitions to a slightly concave
margin at the beginning of the otic process. The otic process is
dorsoventrally deep and less expanded craniocaudally compared
399
FIGURE 6. Dermal denticles of Dracopristis homanorum and the region of the body they were collected from on NMMNH
P-68537. A, Samples of dermal denticles from the nasal region; B, Samples of dermal denticles collected from the anterior dorsal
n region; C, Samples of dermal denticles from the scapularcoracoid region; D, Sample of ank dermal denticles from the pelvic
n region. Scale bars equal 1 mm.
to Ctenacanthus. A short, dorsally directed rectangular process
is present and extends craniocaudally about an eighth of the
length of the otic process. There is an anteriorly directed, square-
shaped ange on the dorso-anterior border of the otic process that
articulates to the postorbital process of the neurocranium. There
is no evidence of an otic articular fossa. The posterodorsal crest
is thickened on the lateral side of the otic process and originates
from the connection of the palatine ramus and extends to the
articular process of the quadradic region of the palatoquadrate.
The posterodorsal crest steadily increases its thickness from the
dorsal most margin of the otic process to the articular process. A
small fossa is present medially at the dorso-anterior border of the
otic process, formed from a dorsoventrally oriented crest. Along
the ventral quadrate condyle margin, a medial notch is present
for the reception of the mandibular knob of the double jaw joint
for Meckel’s cartilage. The articular process is craniocaudally
short with a rounded ventral margin that ends in a posteriorly
directed point. The palatine ramus is dorsoventrally short and
mediolaterally wide, which is laterally convex and slightly
concave medially. The palatine ramus extends just median of
the otic process. The orbital process on the anterior end of the
palatine ramus has a broad triangular shape. A thin medial dorsal
orbital ridge is present and extends to the otic process. Tooth
sulci are present on the palatoquadrate.
The Meckel’s cartilage is 27.5 cm long, measured from
the anterior symphysis to the caudal edge of the articular fossa.
The greatest depth of Meckel’s cartilage is 6 cm, measured
from the dorsoventral margins behind the last tooth family. The
tooth-bearing portion of Meckel’s cartilage is 14.5 cm long. No
individual tooth furrows are present, and CT imaging suggests
the tooth families are set in a continuous dental sulcus. The
dorsal margin of the Meckel’s cartilage is relatively straight until
just posterior to the tooth series where it is inclined dorsally to
the articular fossa. The anterior margin of the jaw symphysis is
rounded ventrally. The ventral margin of the Meckel’s cartilage is
convex just posterior to the jaw symphysis. A ventral mandibular
ridge is present and originates just below the articular fossa,
runs along the lateral ventral margin of the jaw and terminates
just prior to the jaw symphysis. The posterior most section of
the ventral mandibular ridge is thickened and bears a narrow,
pointed, posterior-directed retroarticular process. A prominent
mandibular knob is seen medially, just anterior to the attachment
of the ceratohyal and the articular fossa.
The hyomandibula is 16.8 cm long, measured from its long
axis; 5.1 cm dorsoventrally deep at the anterior end; and 2.6 cm
dorsoventrally deep at its posterior end. The overall morphology
of the hyomandibula shows it was convex dorsally and concave
medially. The anterior end is dorsoventrally expanded with a
thin dorsal ridge, and a slight anterior projection is present. The
left hyomandibula is exposed medially, showing a dorso-anterior
median facet in the same position of this anterior projection and
corresponds to being placed just behind the post orbital process.
A lateral grove originates caudally and extends anteriorly.
Both the left and right ceratohyals are preserved. The right
ceratohyal is exposed medially, showing a ventral shallow groove
three fourths of its length that ends just before the posterior
articulation to the right hyomandibula. The left ceratohyal
can only be seen with computed tomography and is preserved
dorsoventrally. The ceratohyal is two-thirds the length of the
Meckel’s cartilage. The anterior end is rounded mediolaterally
and has an anterior articulation with a short, rod-like hypohyal.
Branchial Arches—The branchial elements of NMMNH
P-68537 are nearly complete on the right side. The left side
is disarticulated and pushed inward to the buccal cavity (Fig.
4). There are ve gill arches, with the anterior being the
largest and the rest gradually decreasing in size posteriorly.
The pharyngobranchials are blade-like cartilages with
bifurcated anterior ends measuring between 35 mm to 31
mm craniocaudally, with the longest found posteriorly. The
epibranchials are simple rods, with the dorsal articulation
consisting of rounded, bifurcated knob-like joints. The ventral
articulations of the epibranchials are slightly rounded ventrally.
400
The longest epibranchial (EP1) is approximately 99 mm long,
and the shortest (EP5) is approximately 39 mm long. The
computed tomography shows the ceratobranchials are longer
than the epibranchials, with the articulation to the epibranchial
consisting of a singular notch and the anterior margin rounded
at the end. Numerous gill rays are preserved along the anterior
ends of the epibranchials and ceratobrachials, which consist
of thin narrow rods; between 30 mm to 25 mm in length, the
most numerous are found around the rst branchial arch and the
ceratohyal/epibranchial articulation. Only a few disarticulated
hypobranchials can easily be discerned from the computed
tomography scans, which indicate that they are rectangular
in shape and about half the length of the anteriorly directed
ceratobranchials.
Axial skeleton and Caudal Fin—The axial skeleton in
NMMNH P-68537 is nearly complete. Computed tomography
scans show at least six cervical elements preserved in the head
jacket, and they are articulated to the occipital cotylus. Only the
simple outlines of the cervical series can be discerned and viewed
dorsoventrally, but they show that the cervical elements were
wide lateromedially and short anteroposteriorly. Approximately
86+ neural arches can be seen, with the best preserved example
seen in the thoracic region, found between the anterior and
posterior dorsal ns. The thoracic axial skeleton consists of 65
fused, rod-like cartilages that form the neural arches and are in
close association with one another. The most anterior neural
arches, just behind the anterior dorsal spine, are approximately
51 mm long and distinctly have a downward facing neural
arch with a posteriorly directed neural spine. As you progress
further along the thoracic series, the neural arches become more
elongated, with the neural arch itself projecting anteriorly. The
most posterior neural arches are approximately 80 mm in length,
with the neural spine greatly inclined posteriorly and the neural
arch angled anteriorly. The peduncular region is approximately
a little over half the length of the thoracic region and can only
be faintly seen as it consists of thinly constructed, rod-like
cartilages. The neural arch cartilages of the peduncular region
are more greatly inclined posteriorly and become gradually
smaller posteriorly. The proximal ends of six haemal arches are
present at the posteriormost segments of the peduncle region;
the distal ends of these elements presumably were lost during
eld extraction. Due to the incomplete nature of these elements,
it is dicult to ascertain whether or not these cartilages were
part of the anteriormost section of the hypochordal lobe of the
caudal tail.
The caudal n of Dracopristis homanorum is completely
articulated and undistorted (Fig. 7). Unfortunately, the joint
between the tail block and the body blocks when extracted
from the KBQ was heavily weathered, and that section was
lost. It is possible that the ventral anterior most section of the
caudal n was lost or may be part of the proximal haemal arch
cartilages from the peduncular region described above. The
caudal n is heterocercal with the hypochordal lobe supported
by an endoskeleton of haemal arches and n radials. The total
height of the caudal n, measured from the ventral margin of the
hypochordal lobe to the apex of the epichordal lobe, is 40 cm.
The length of the hypochordal lobe is 33.5 cm, and the length of
the epichordal lobe is 34 mm. The hypochordal lobe is positioned
at a near right angle to the epichordal lobe of the caudal n.
The hypochordal lobe in the tail block of NMMNH P-68537 has
preserved the distal ends of the rst two anterior haemal arches
which are dorsalventrally tall and anteroposteriorly thin. The
last three haemal arches that support the hypochordal lobe are
anteroposteriorly broader than the anterior haemal arches. The
anterior proximal n radials are reduced in height, with the rst
two anterior proximal n radials supporting a small triangular
distal n radial, while the third proximal n radial shares a distal
n radial with the fourth proximal n radial. The fourth distal n
radial is enlarged and greatly elongated anteroposteriorly. The
fth, sixth and seventh distal radials are shortened elements that
seem to support the proximal end of the seventh distal radial.
The ninth haemal arch has a single distal radial. The impression
of the ceratotrichia of the hypochordal lobe lends support to the
conclusion that this section of the caudal n was angled more
posteriorly than ventrally from the body, giving a sharp cresent
shape to the hyopchordal n margin. The epichordal lobe is
supported ventrally by the dorsally curved section of the hemal
arches, which steadily decrease in size posteriad. The dorsal
margin of the epichordal lobe of the caudal n is supported
by long rectangular basidorsal elements that support long thin
supraneural elements. The impression of the ceratotrichia of the
epichordal lobe suggests it was anteroposteriorly broader than
the hypochordal lobe and bluntly rounded at its apex.
Unpaired Fins and Spines—Dracopristis homanorum
bears two prominent dorsal n spines, both exposed on their
right lateral sides and articulated to basal plates bearing n
radials (Fig. 8). Both dorsal spines bear lateral longitudinal
costae ornamented with rows of minute (1.5 to 1.8 mm wide)
transverse denticles that are elliptical anteriorly and become
rounded posteriorly. These denticles bear small, thin stellate
ridges. The anterior most costa is a smooth band with some
small transverse ridges along its outer margins. Wear facets are
present on the anterior costae near the tip of the anterior spine.
Two single rows of slightly larger, posteriorly directed hook-
like denticles are present on the upper third of the posterolateral
margin of each spine. The anterior dorsal spine is approximately
27% of the total body length of D. homanorum, with a greatest
length of 57 cm, is 5.3 cm wide, and is distally recurved.
The rst dorsal spine is laterally compressed but bears a
posterolateral ridge that begins at about the upper half of the
spine body and grades back near the upper fourth of the spine.
A posterior median ridge is present that originates just above
the groove for the basal plate and ends near the upper fourth of
the spine apex. The rst basal plate is triangular in shape, with
an anteroposterior length of 17 cm and a dorsoventral height of
11 cm. There are approximately ve long, recurved n radials
articulating with the posterior margin of the basal plate. The
rst upper three n radials articulate directly to the basal plate,
and the lower two n radials are attached to additional cuboidal
cartilages on the basal plate. The impression of the dorsal n
ceratotrichia shows the dorsal n was continuously attached to
the n spine.
The second dorsal n spine is more erect than the anterior
dorsal spine, and in preserved lateral view it is 40 cm long and
4 cm wide. The second dorsal spine is less laterally compressed
than the anterior dorsal spine and bears a thin lateral ridge that
originates at the beginning of the costae rows and terminates
about a third up the spine. This lateral ridge is rounded, with
the longitudinal costae following along the posterior side of
the ridge, suggesting this is not an artifact of postmortem
compression. The posterior margin of this spine is relatively at,
bearing no median ridge. The basal plate of the posterior dorsal
n is steeply triangular, with an anteroposterior length of 11.5
cm and a dorsoventral height of 15.5 cm. The basal plate has
eight thin triangular n radials; the rst three articulate directly
to the basal plate, with the remaining ve articulating with four
rectangular intermediate radials that are attached to the basal
plate. The traces of the ceratotrichia of the posterior dorsal n
suggest that the n was tall, but anteroposteriorly narrow, and
the n ap was conuent with the spine to its apex.
The anal n is present, supported by a cartilaginous plate.
Dermal denticles and impression of the ceratotrichia suggest the
anal n was a short, rounded, lobate n.
Pectoral girdle—The pectoral girdle of NMMNH
P-68537 is split between the head and body blocks and
exposes the scapulocoracoids, the right pectoral n, and part
401
FIGURE 7. The caudal n of Dracopristis homanorum and
comparison to other ctenacanth and symmoriid sharks. A-C,
NMMNH P-68537, A, photograph, B, surface scan, C, line
drawing overlay of surface scan showing skeletal features and
body outline of caudal n; D-G Line drawings of caudal ns
showing the relationship of the hemal arches (green), proximal
n radials (white), and distal n radials (orange) (drawings not
to scale), D, Dracopristis homanorum, E, “Ctenacanthus”
costellatus (modied from Moy-Thomas, 1936), F,
Goodrichthyes eskdalensis (modied from Moy-Thomas, 1936),
G, Akmonistion (Stethacanthus) zangerli (modied from Coates
and Sequeira, 2001). Scale bars equal 10 cm.
of the left pectoral n (Fig. 9A-B). The scapulocoracoids are
fused together at the coracoids, which have an anteriorly
directed, narrow triangular process. This coracoid process is
in close association with the gill arches. The complete right
scapulocoracoid is exposed laterally and is 38.5 cm tall, 10
cm wide dorsally, and has a mediolateral thickness of 6 cm.
The left scapulocoracoid is exposed medially and is missing
the upper third of the scapular process. Dorsally, the scapular
process is expanded into a long, pointed, anterodorsal margin
and a short pointed posterodorsal process. The dorsal apex
between the anterodorsal and posterodorsal process is slightly
concave. A convex and dorsoventrally broad process is present
on the posterior margin of the long axis of the scapular process,
and is positioned between the posterodorsal process and the
articular region. A deep lateral, though craniocaudally narrow,
depression is present that originates towards the anterior end of
the coracoid and terminates just below the dorsal apex of the
scapular process. A second shallower lateral grove is present just
above the margin of the convex posterior process. A small knob
is present on the anterior margin of the coracoid, positioned just
below and opposite to the glenoid process. The glenoid process
is square-shaped, approximately 3 cm wide dorsoventrally and
3.5 cm deep craniocaudally. A shallow, U-shaped depression is
present on the lateral surface of the glenoid, and, on the medial
side, a shallow depression is present on the glenoid that extends
to the coracoid. A thickened ridge is present on the anterior
medial margin of the scapulocoracoid.
The articulated right pectoral n is nearly complete,
though part of the metapterygium, the posterior axial cartilage,
and the lower apex of the ceratotrichia were damaged during
eld extraction. The left pectoral n is partially disarticulated
but closely associated together. The pectoral n had a tribasal
articulation from the propterygium, mesopterygium, and
metapterygium. The propterygium is narrow and elongate, at
7 cm in height and 1.5 cm wide at the proximal articulation.
The meospterygium is rectangular in shape at 3 cm height, and
1.5 cm wide. The metapterygium is trapezoidal in shape and
is 4 cm in height and approximately 5 cm in width. A single,
slightly recurving, axial cartilage is present though damaged.
It is approximately 12 cm long and dorsoventrally narrow.
A secondary trapezoidal cartilage is present that articulates
ventrally with the mesopterygium and the anterior margin of the
metapterygium. This secondary cartilage is 3 cm in height and
3 cm at its widest.
There are 21 proximal and distal n radials forming
an arch-like arrangement of the endoskeletal support. The
proximal radials articulate with the propterygium, the secondary
cartilage, the metapterygium, and the posterior axial cartilage.
The proximal n radials are rectangular thin cartilages that
begin small anteriorly, increase in length medially, and then
become increasingly smaller posteriorly. The distal n radials
are triangular thin cartilages, shorter in length anterior to the
proximal radials. The median series of distal n radials is as long
as or longer than the proximal radials, which in turn decrease in
length posteriorly. The endoskeletal, ceratotrichia, and dermal
denticle outline of the pectoral n suggest that the pectoral
n was proportionately large (estimated mediolateral width
of 36 cm and anteroposterior length of 25 cm), triangular and
aplesiodic. Dermal denticles and ceratotrichia impressions show
the anterior margin of the n was shallowly concave with the
posterior margin straight with a sharply pointed posterior lobe.
Pelvic girdle—The right and left pelvic girdles are exposed,
measuring 9.5 cm mediolaterally and 7 cm anteroposteriorly.
They are triangular in shape with rounded lower anterior
margins. The narrow, square-shaped medial ends of the girdles
are in close approximation to one another but not fused. The
right pelvic n is in near perfect articulation with, though slightly
detached from, the pelvic plate. The pelvic n endoskeleton is
402
FIGURE 8. The dorsal ns and dorsal spines of Dracopristis homanorum. A-D, The anterior dorsal n, A, Photograph of anterior
dorsal n expose on the right side, B, Line drawing overlay of surface scan, C, Close up of the apical tip of anterior dorsal n spine
showing the posterior denticles and denticulated costae rows, D, Close up of the smooth anterior costae; E-F, The posterior dorsal
n, E, Photograph of the posterior dorsal n exposed on the right side, F, Line drawing overlay of surface scan. Scale bars of A-B
and E-F equal 10 cm; Scale bars of C-D equal 1 cm.
supported by a series of 14 proximal and distal n radials. No
basal cartilages are preserved but are suggested by the space
between the right pelvic girdle and its corresponding radials.
The proximal n radials consist of thin rectangular cartilages
that are short anteriorly and posteriorly, with the centrally
positioned cartilages longer. The distal n radials are long, thin
triangular cartilages, typically much longer than the proximal
radials. The n radials extend to the margins of the pelvic n,
which has an overall dimension of 21 cm wide mediolaterally
and 18 cm long anteroposteriorly. The anterior margin of the
pelvic n was angled posteriorly and straight, then recurves
broadly posteriorly. No clasper cartilages are present, suggesting
that NMMNH P-68537 was a female.
Comparison
Neurocranium—The neurocranium of Dracropristis
homanorum shares many features morphologically with
Tamiobatis vestus (NMNH 1717 vide Romer, 1964), “Tamiobatis
sp.” (AMNH 2140, vide Schaeer, 1981; CMNH 9280 vide
Williams, 1998), Ctenacanthus concinnus (CMNH 6219 and
CMNH 7852), Heslerodus divergens (FMNH PF 8170, vide
Williams, 1985; Stahl, 1988), Cladodus elegans (BGS 56574,
Ginter and Maisey, 2007) and xenacanths (Schaeer, 1981) in
having a reduced rostrum, wide precerebral fontanelle, wide
orbital shelf, wide postorbital process, elongated otic region,
presence of a dorsal otic ridge, and the presence of a lateral
otic process (except in Cladodoides). The precerebal fontanelle
in Dracopristis, and, where preserved in other ctenacanths,
has a more v-shaped and more deeply incised precerebral
frontanelle compared to symmorriids, cladoselachians, and
euselachians. Xenacanths and Doliodus problematicus have
a similar feature of a mediolaterally wide opening for the
403
precerebral frontanelle, but it is less anterorposteriorly deep
and typically U-shaped (Schaeer, 1981; Maisey et al., 2009).
In symmoriiform chondrichthyans the precerebral fontanelle is
mediolaterally narrow and anteroposteriorly elongated (Maisey,
2007). In comparison with the holotypes of Tamiobatis vetustus
(USNM 1717; Romer, 1964) and Cladodoides wildungensis
(Forschungsintitut un Naturmuseum Senckenberg, Frankfurt,
P2468; Maisey, 2001, 2005), the precerebral fontanelle of D.
homanorum is a less mediolateral wide V-shape opening. The
mediolateral width of the precerebral fontanelle is similar in
dimensions to Ct. concinnus (Ginter and Maisey, 2007, g. 9A).
Dracopristis shows a complete internasal plate, a feature missing
or fragmentary in most ctenacanth neurocranial specimens. The
preorbital processes in D. homanorum are similar in structure
to that seen in T. vetustus and “Tamiobatis sp.,” being two
anteriorly directed structures, but more mediolaterally broad
with a deep V-shaped notch for the supercial ophthalmic ramus,
which is shallow in the two latter forms. Ct. concinnus has
proportionately very large U-shaped notches for the supercial
ophthalmic ramus (Ginter and Maisey, 2007, g 9A).
The preorbital processes in xenacanths are T-shaped,
with the notch for the supercial ophthalmic ramus curving
anterolaterally (Schaeer, 1981). There are no preorbital
processes in symmoriiform chondrichthyans (Maisey, 2007).
The orbital shelf of Dracopristis is broad mediolaterally, similar
in proportion to that seen in Ctenacanthus and Heslerodus. The
orbital shelf is narrower in Tamiobatis vetustus, “Tamiobatis
sp.,” and Cl. elegans. The postorbital process in D. homanorum
is anteroposteriorly broad, similar to that seen in “Tamiobatis
sp.” and Ct. concinnus. In C. wildungensis, T. vetustus, and Cl.
elegans, the postorbital process is anteroposteriorly narrow. A
broad anteroposterior postorbital process is also a feature seen
in xenacanths, diering in that the post orbital process does not
extend out as far laterally as in the above taxa (Schaeer, 1981).
The dorsal otic ridge in D. homanorum originates anterior to
the posterior margin of the postorbital process and extends over
to just anterior of the otic-occipital ssure, with a chisel-like
posterior margin, a trait similar to Ct. concinnus, which only
diers in having a thin, pointed posterior margin. In “Tamiobatis
sp.” the dorsal otic ridge also originates just anterior to the
posterior margin of the postorbital process, but just before the
anterior margins of the lateral otic process it has an elliptical
posterior margin. In T. vetustus the dorsal otic ridge originates
just anterior to the posterior postorbital process, and it ends
just before the anterior margin of the lateral otic process with
an elliptical posterior margin. In C. wildungensis the dorsal otic
ridge is a small structure. It is dicult to discern if it originates
anterior to the posterior margin of the postorbital process or
posterior to the postorbital process and extends just anterior to
the otic-occipital ssure with a thin pointed margin.
It has been proposed that Cladodoides represents either a
basal ctenacanthiform (Ginter, et al., 2010) or a taxon basal to the
cladodontomorph sharks (Ivanov, 2018). The dorsal otic ridge
also occurs in xenacanths, which originates just anterior to the
posterior margin of the postorbital process and terminates just
anterior to the otic process, with the posterior margin having an
elliptical shape (Schaeer, 1981). In Dracopristis, Ctenacanthus,
Tamiobatis vetustus, “Tamiobatis sp.,” and Heslerodus, the
lateral otic process, with its articulating facet, projects laterally.
In Dracopristis, Heslerodus, and Ctenacanthus the articular
facets are square shaped, while Tamiobatis vetustus and
“Tamiobatis sp.” dier in having an elliptically shaped articular
facet. A lateral otic process is hypothesized to have been present
in Cl. elegans but it is not present in Do. problematicus or C.
wildungensis (Maisey, 2007; Maisey et al, 2009). In xenacanths,
the otic process is present but projects posteriorly (Schaefer,
1981). An otico-occipital ssure is present in D. homanorum,
and is also present in Do. problematicus, C. wildungensis, Ct.
concinnus, T. vestus, “Tamiobatis sp.,” Cl. elegans, xenacanths,
and symmorrids (Romer, 1964; Schaeer, 1981; Maisey, 2001,
2005, 2007; Maisey et al., 2009). There is no medial crest present
on the occipital arch in D. homanorum, C. wildungensis, and
Ct. concinnus, but it is present in T. vetustus, “Tambiobatis sp.,”
xenacanths, and possibly Cl. elegans (Schaefer, 1981; Maisey,
2007; Ginter and Maisey, 2007).
Teeth and Squamation—The dentition of Dracopristis
homanorum is considered to be ctenacanthiform based on
having a wide and short, lingually extending tooth base, which
is reniform in shape, an orolingual and basolabial structure
that is wider than the median crown, presence of a basolabial
depression, and the enameloid of the crown connected between
the cusps (Ginter et al., 2010). Ctenacanths such as Cladodus,
Goodrichthys, and Ctenacanthus have a single ridge that forms
the basolabial and orolingual projection, and ctenacanths such
as “Tamiobatis,” Saivodus, and Neosaivodus have divided,
basolabial tab-like projections, and a single orolingual ridge
(Fig. 5I-N; Dun and Ginter, 2006; Ginter, 2010; Ginter et
al., 2010; Hodnett et al., 2012). The dentition of Dracopristis
shares a number of features of the tooth base with the ctenacanth
taxa Glikmanius, Heslerodus, Kaibabvenator, Glencartius
and Nanoskalmae (Ginter et al., 2010; Hodnett et al., 2012;
Ginter and Skompski, 2019). These taxa have distinct, divided
orolingual and basolabial projections, however, the projections
vary in size, shape, and positioning in terms of their placement
along the midline of the tooth, and how the orolingual projections
are placed between the median and the lingual rim of the tooth
base. In Dracopristis the orolingual and basolabial projections
are widely spaced from the midline of the tooth, positioned
proximately on the mesiodistal margins of the tooth base,
and the orolingual projections are proportionately large ovate
pads. This is similar to what is seen in Glikmanius, but there
is variance in the position of the orolingual projections. The
orolingual projections in G. occidentatlis are positioned closer
to the lingual rim of the tooth base; in G. myachkovensis they are
closer to the cusps (Ginter et al., 2010; Hodnett et al., 2012). The
midline position of the basolabial and orolingual projections
in Kaibabvenator and Glencartius are proportionately less
wide than in Dracopristis and Glikmanius, and the basolabial
and orolingual projections in Kaibabvenator are more
circular than ovate, as seen in Dracopristis, Glikmanius, and
Glencartius (Hodnett et al., 2012; Ginter and Skompski, 2019).
The orolingual and basolabial projections in Heslerodus and
Nanoskalme are circular in shape and tend to be positioned
closer to the midline than the taxa discussed above (Hodnett et
al., 2012). The basolabial depression is shallow, similar to that
seen in Kaibabvenator, Nanoskalmae, and Glencartius, whereas
in Glikmanius and Heslerodus the basolabial depression is well
dened.
The cusps of Dracopristis are distinct from those of all
other ctenacanths in their proportionately shorter height and
broad triangular shape (Fig. 5I-J). Even the juvenile tooth
fragment shows relatively short cusp height and diers from the
adult dentition in having rounded cusps. All other ctenacanths
have proportionately tall cusps that vary in mesiodistal widths,
depending on species (Dun and Ginter, 2006; Ginter et al.,
2010; Hodnett et al., 2012). The cristae pattern of the cusps in
Dracopristis is similar to Glencartius in having coarse, well-
dened cristae on the labial and lingual sides of the cusps, but
Glencartius lacks the v-shaped cristae seen in Dracopristis.
Teeth of Heslerodus also have v-shaped cristae, but they are few
in number and only present on the labial side of the cusps (Fig.
5K-L). Glikmanius has multiple, ne longitudinal cristae on the
labial and lingual sides of the cusps, Nanoskalmae only has two
to three cristae on the labial and lingual sides of the cusps, and
the cusps of Kaibabvenator lack cristae (Hodnett et al., 2012).
Retention of post-functional tooth rows on the labial surface
404
of the jaws is demonstrated in both Dracopristis (presented
here) and Ctenacanthus concinnus (Williams, 2001), though
the signicance of this feature is still not well understood.
Williams (2001) noted that tooth retention and slow rotation in
“cladodont” sharks may be a primitive feature, and that the teeth
themselves were rotated into outer tooth row pockets under the
dermis. No mineral absorption was observed in the Ctenacanthus
specimens (Williams, 2001), and none can be seen in NMMNH
P-68537, suggesting that these post-functional teeth are not used
as mineral storage.
The dermal denticles of Dracopristis are of the “typical”
ctenacanth morphology as described by Reif (1978), Williams
(1998), and Ginter and Skompski (2019). Williams (1998)
identied at least four denticle types from CMNH 9280: Type I
and Type II are rectangular, thin-walled, attened and recurved
denticles with closely spaced triangular ridges, with Type II
having the ridges slightly thicker and raised; Type III denticles
have numerus bulbous cusps and are much thicker than Type
I and Type II denticles; Type IV denticles are round, with
stellate ridges radiating from the central region. Examination of
NMMNH P-68537 has shown that Dracopristis homanorum
denticles are nearly identical to those of CMNH 9280,
“Tamiobatis sp.” The Type I and Type II denticle morphotypes
in Dracopristis were collected from regions behind the cranium
and become broader dorsoventrally near the tail and should be
considered as body denticles. Type III and Type IV denticles
were collected only from the cranium. Viewed aborally, these
denticles share in common numerous foramina along the outer
edge of the denticle base. As discussed by Reif (1977) and
Williams (1998), the aboral bases to the thin walled denticles
(body denticles) are ovate in shape and concave. Facial denticles
have circular-shaped, aboral concave bases. The denticles of
Dracopristis also have numerous aboral ridges on the aboral
surfaces of the denticles and growth rings on the aboral concave
base (Reif, 1977).
Mandibular and hyoid arches and suspensorium—
In comparison to other proposed ctenacanths, the jaws
of Dracopristis are proportionately deep, robust, and
anteroposteriorly shorter than seen in Ctenacanthus and
Heslerodus, and, in turn, these three taxa have more robust jaws
than Cl. elegans, “Tamiobatis sp.” (CMNH 9280, Williams,
1998), and CM 46006 (Hodnett et al., 2016), which have
proportionately longer and narrower jaws. The palatoquadrate
of D. homanorum and other proposed ctenacanths such as
Ctenacanthus, Heslerodus, and CM 46006, share a unique
feature in a square-shaped anteriorly directed ange on the
anterodorsal margin of the otic process (Fig. 10). Referred to
here as the anterodorsal process, this projection is mediolaterally
compressed with a small shallow notch present on the medial
side and is either attened or slightly curved laterally. The
presence of an anterodorsal process in Cladodus elegans (BGS
56574A, Ginter and Maisey, 2007) is dicult to discern, as
the palatoquadrate is exposed medially. The condition of the
palatoquadrates of CMNH 9280 (Williams, 1998) also obscures
whether or not an anterodorsal process was present. Orientation
and articulation of the anterodorsal process is demonstrated
in two articulated crania of Ctenacanthus (CMNH 6219 and
CMNH 7852), which show the anterior otic ange placed
posteriorly and slightly overlapping the postorbital process. In
sharks with an amphistylic suspensorium, the articulation of the
anterior margin of the otic process of the palatoquadrate is on
the posterior margin of the postorbital process (Maisey, 1980,
2008; Schaeer, 1981; Wilga, 2005). However, in forms such as
Orthacanthus there is no indication of an anterodorsal process
but rather a broad, boss-like articulation that covers most of
the posterior surface of the postorbital process (Maisey, 2008).
Symmoriids have the addition of a lateral fossa on the anterior
point of the otic process (Lund, 1974, 1984, 1985, 1986;
FIGURE 9. The paired ns of Dracopristis homanorum. A-B,
The right pectoral n, A, surface scan, B, line drawing overlay
showing skeletal features and extent of ceratotrichia; C-D,
Comparison of the pectoral n of Ctenacanthus concinnus and
Dracopristis homanorum (not drawn to scale), C, Dracopristis
homanorum, D, Ctenacanthus concinnus; E-F, The right
pelvic n of Dracopristis homanorum, E, surface scan, F,
line drawing overlay showing skeletal features and extent of
ceratotrichia. Scale bars equal 10 cm.
405
Zangerl and Case, 1976; Coates and Sequeira, 2001), a feature
absent in Dracopristis and other proposed ctenacanths. The
purpose of the anterodorsal process may be to act as a secondary
support and articulation to tightly brace the palatoquadrates to
the neurocranium, together with the primary articulations with
the postorbital, ethmoid and otic processes (Maisey, 2008). The
anterodorsal process may be an autapomorphic trait present in
ctenacanths. Cladodoides wildungensis has been proposed as
a primitive ctenacanthiform (Ginter et al., 2010) or as a taxon
with a close relationship with ctenacanths, xenacanths, or
symmorriids (Maisey, 2005). However, the palatoquadrates of
Cladodoides wildungensis lack an anterodorsal process (Gross,
1937, 1938). Dracopristis lacks the rectangular dorsal facet
seen in CM 46006 and CMNH 9280 (Williams, 1998; Hodnett
et al., 2016).
Dracopristis homanorum also shares with other proposed
ctenacanths a well-developed lateral dorsal crest that extends
from just behind the anterior otic ange and follows the dorsal
margin of the otic process to the quadrate process of the
palatoquadrate, a ventral mandibular ridge that originates just
below the articular cotylus of Meckel’s cartilage and extends to
over half of the ramus, the presence of a retroarticular process,
and a well-developed ethmoid process. The lateral dorsal
crest in Dracopristis is similar to that of Heslerodus, which
is expanded dorsoventrally. In Ctenacanthus (CM 46006 and
CM 9280), as described by Williams (1998), the lateral dorsal
crest is proportionately thinner. In most xenacanths the lateral
dorsal crest is robust but does not extend down to the quadrate
process (Hotton, 1952; Heidtke et al., 2004). In symmorriids the
lateral dorsal crest appears to be underdeveloped, the exception
possibly being Oresticanthus fergusi in which the lateral dorsal
crest seems moderately developed (Lund, 1974, 1984, 1985,
1986; Zangerl and Case, 1976; Coates and Sequeira, 2001).
The ventral mandibular ridge of the Meckel’s cartilage in
Dracopristis is robustly constructed, like that seen in Heslerodus,
whereas in Ctenacanthus and CM 46006 the ventral mandibular
ridge is thinly constructed (Figure 10). Unfortunately, the
Meckel’s cartilage is too poorly preserved in CMNH 9280 for
comparison purposes. Xenacanths have a ventral mandibular
ridge that extends primarily from the mid portion of the lateral
surface of the jaw and does not extend to the articular cotylus
(Hotton, 1952; Heidtke et al., 2004). In symmoriids, the ventral
mandibular ridge is restricted to a v-shaped lateral indentation
positioned just prior to the mid portion of the jaw (Lund, 1974,
1984, 1985, 1986; Zangerl and Case, 1976; Coates and Sequeira,
2001). The retroarticular process on the Meckel’s cartilage in
Dracopristis is dorsoventrally deep, similar in proportion to
Heslerodus, though both taxa are less robust than is seen in
Ctenacanthus and CM 46006, which resemble the condition
seen in some xenacanths (Hotton, 1952). A retroarticular process
is absent in symmorriids and Cladodoides (Gross, 1937, 1938;
Coates and Sequeira, 2001).
The features of the palatoquadrate and Meckel’s cartilage
of Dracopristis homanorum and other ctenacanths suggest
these taxa had a amphistylic suspensorium that rmly braced
the palatoquadrate to the neurocranium. This arrangement
allows for a robust adductor mandibulae as demonstrated by
the well-developed lateral dorsal crest of the upper jaw and the
ventral mandibular ridge of the lower jaw extending more than
half the length of the ramus. This is similar to the amphistylic
arrangement and musculature seen in xenacanths, which also
bear well developed, though not as extensive, lateral dorsal
crests and ventral mandibular ridges (Hotton, 1952).
Postcranial skeleton—The proportional dimensions of the
dorsal n spines to the body length of Dracopristis homanorum
are impressive. The rst dorsal spine is 27% of the body
length in NMMNH P-68537, whereas the two more complete
ctenacanth endoskeletons, of Glencartius (BMNH P. 5900,
data converted from Traquair, 1884) have a rst dorsal spine-
to-body ratio of 17%, and Goodrichthyes eskdalensis (NMS
1950.38.46, data from Moy-Thomas, 1936) has an anterior
dorsal spine-to-body ratio of only 9%. Compared to other
similarly large spine elasmobranchs from the Carboniferous, the
proportions of the anterior dorsal spine-to-body-length ratio in
the euselachian Tristychius arcuatus is approximately 18% (data
from reconstruction by Dick, 1978) and approximately 21 % in
the basal hybodontiform Onychoselache traquairi (data from
reconstruction by Coates and Gess, 2007). This suggests that
presently Dracopristis may have had one of the highest spine-
to-body ratios seen in any Carboniferous elasmobranch.
The ornamentation morphology of the dorsal spines in
Dracopristis is Ctenacanthus-like in which the lateral sides are
ornamented with multiple longitudinal costae that have small,
closely spaced circular and elliptical denticle-like tubercles.
Dracopristis diers from Ctenacanthus sensu stricto (Maisey,
1981) in that the anterior costa is primarily smooth. This smooth
anterior costa has also been described in “Ctenacanthus”
amblyxiphias (Cope, 1891) and “Ctenacanthus” lamborni
(Wells, 1944), both of which are known from Pennsylvanian
localities. Maisey (1984) considered both taxa to be placed
in a genus separate from Ctenacanthus. Recently, Ginter
et al. (2010) noted the occurrence of “Ct.” amblyxiphias
spines associated with pectoral skeletal elements and teeth of
Glikmanius occidentalis from the lower Permian of Nebraska.
It should be noted that Wells (1944) established “Ct.” lamborni
based on dimensional dierences from “Ct.” amblyxiphias, even
though both share near identical ornamentation. From what is
observed in Dracopristis, the proportional dierences between
“Ct.” amblyxiphias and “Ct.” lamborni could be due to the fact
that one spine could be the larger anterior dorsal spine (“Ct.”
lamborni) and the other the more gracile and straighter posterior
dorsal spine (“Ct.” amblyxiphias). The record of Glikmanius
teeth in association with “Ct.” amblyxiphias spines (Ginter et
al., 2010) strongly suggests that Ctenacanthus-like spines with
smooth anterior costae belong to more than one ctenacanth
species. This is because Glikmanius and Dracopristis dier
signicantly in tooth morphology, and these spine morphologies
are shared at a family level rather than a specic level.
Like Glencartius and Goodrichthyes eskdalensis, the
dorsal spines of Dracopristis are supported by a triangular
basal cartilage. Dracopristis diers from Glencartius and
Goodrichthyes in having a series of singular n radials on the
anterior basal cartilage supporting the dorsal n. A similar trait
is seen in CM 46006, which also has small singular n radials
(Hodnett et al., 2016). It is possible that the anterior basal
cartilage of Glencartius and Goodrichthys may have also bore n
radials, but the condition of these specimens obscures evidence
of their presence. The posterior dorsal n radials in Dracopristis
are similar to Goodrichthys in which the anterior portion of the
dorsal n has single n radials attaching to the basal cartilage,
and the posterior n radials are attached to secondary cuboidal
cartilages that are attached to the basal cartilage (Moy-Thomas,
1936). Dracopristis diers, however, in having a narrower
dorsal n than Goodrichthys. In Glencartius, the n radials
attach directly to the basal plate with no intermediate cuboidal
cartilages present (Moy-Thomas, 1936).
The pectoral skeleton of Dracopristis is similar to that
seen in Ctenacanthus in having the posterior margin of the
scapula forming a distinct concave margin that then grades
into a rounded posterior ange just above the glenoid process.
A similar condition is seen in the holotype of Glencartius but
diers in that the dorsal posterior concavity is sharply notched,
and the posterior ange is nearly triangular in shape and more
dorsoposteriorly directed. Reconstruction of the pectoral n
suggests it had a tribasal articulation with a long basal bar
that supported the majority of the radials. This arrangement
406
FIGURE 10. Mandibular arches of ctenacanths and the articulation of anterodorsal process. A-B, Dorsal view of CMNH 6219,
Ctenacanthus concinnus from the Cleveland Shale. A, Photo of specimen. B, line diagram of CMNH 6219, note the overlapping
articulation of anterodorsal process. C-F. Palatoquadrates and Meckel’s cartilage in right lateral view of various ctenacanth taxa
showing the major shared features of the jaws. C, CM 46006, Bear Gulch taxon. D, Heslerodus divergens, composite of FMNH PF
8170 and 8212, redrawn from Williams (1985). E, NMMNH P-68537. F, Ctenacanthus concinnus CMNH 9450. Scale equals 1 cm.
407
is also seen in Ctenacanthus specimens from the Cleveland
Shale (AMNH 189, CMNH 6219, and CMNH 7852) and CM
46006. Moy-Thomas (1936) reconstructed the pectoral n
of Glencartius with a tribasal articulation, but with a series
of block-like basal cartilage, though this may be erroneous
due to the condition of the specimen. Dracopristis diers
from Ctenacanthus, Glencartius, and CM 46006 in having an
elongated propterygium, a secondary square-shaped cartilage
between the metapterygium and the proximal radials, and
pectoral n ceratotrichia that are aplesodic. Ctenacanthus,
Glencartius, and CM 46006 have pectoral ns that are plesodic
(Dean, 1909; Moy-Thomas, 1936; Hodnett et al., 2016). The
basal xenacanth Diplodoselache woodi also has a tribasal
articulation for the pectoral n (Dick, 1981), while more derived
xenacanths have a single basal articulation (Schneider and Zajic,
1994; Heidtke et al., 2004).
The pelvic girdle of Dracopristis homanorum is unfused,
triangular-shaped, and directly support a series of radials. This
trait of the pelvic girdle is also seen in Glencartius, CM 46006,
and xenacanths, which also have unfused triangular-shaped
pelvic girdles that support a series of radials (Moy-Thomas,
1936; Dick, 1981; Schneider and Zajic, 1994; Heidtke et al.,
2004). In CM 46006, posterior to the pelvic girdle the other
pelvic n radials articulate to a series of square-shaped basal
cartilages. Presently we cannot see this series of square-shaped
basals posterior to the pelvic plate attaching to the posterior
n radials in NMMNH P-68537. This may be due to these
elements being poorly calcied in this particular individual or
still obscured by matrix. Information on the posterior end of the
pelvic n is limited in other ctenacanth taxa. This arrangement of
having a series of square-shaped basal cartilages that support n
radials is a trait shared with xenacanths (Dick, 1981; Schneider
and Zajic, 1994; Heidtke et al., 2004). In symmoriids, the pelvic
n radials are primarily supported on the pelvic girdle and the
metapterygial axis (Lund, 1985, 1986; Coates and Sequeira,
2001). The overall shape of the pelvic n of Dracopristis is
similar to CM 46006 in which the pelvic n has a near teardrop-
like shape, with Dracopristis comparatively being more robust
anteriorly and shorter craniocaudally, while CM 46006 is
narrower and more elongated craniocaudally.
For comparison of the caudal n of Dracopristis, only
Glencartius, Goodrichthys eskdalensis and CM 46006 are
ctenacanths with articulated caudal ns. All four taxa have
heterocercal caudal ns, with the epichordal lobe composed
of basidorsal elements that support supraneural elements.
The basidorsal and supraneural elements of D. homanorum
are rectangular in shape and are dorsoventrally taller than the
other three taxa. The hypochordal lobe of the caudal n of D.
homanorum is perhaps the most unique when compared to the
other three ctenacanth sharks. D. homanorum has nine radials
supporting the endoskeleton of the hypochordal lobe, while “Ct.”
costellatus and CM 46006 have 10 radials, and Goodrichthys
has 11. D. homanorum also lacks intermediate basal cartilages
between the haemal arches and the proximal n radials, while
Glencartius has the rst six anterior radials with intermediate
basal cartilages (Moy-Thomas, 1936). Goodrichthys has nine
intermediate basal cartilages attaching the proximal n radials,
starting just after the second n radial. In CM 46006, there at
least ve intermediate basal cartilages seen on the specimen, and
possibly others attaching to the n radials.
The most striking feature of the hypochordal lobe of
Dracopristis is the distal radials. Most of the distal radials in
Dracopristis are reduced in size, the exception being the fourth
distal radial, which is attached to the third and fourth proximal n
radial. The fourth distal radial is enlarged and elongated, forming
the primary support of the distal section of the hypochordal lobe.
In Glencartius, Goodrichthys, and CM 46006, the distal radials
are nearly equal in height or slightly longer than the proximal
radials. Goodrichthys is also the only ctenacanth with bifurcated
distal radials. Diplodoselache also has a heterocercal tail that
has a hypochordal lobe supported by radial elements, though in
a reduced number (Dick, 1981). Symmoriids like Akmonistion
and Cobelodus have a greater number of n radials (15-20)
supporting the hypochordal lobe of the heterocercal tail and
much more elongated distal radials (Zangerl and Case, 1977;
Coates and Sequeira, 2001).
Relationships—The morphology of the dentition of
Glikmanius and the new taxon Dracopristis have been suggested
to have a close association with other cladodont-bearing sharks
such as the symmoriids and cladoselachians in the superorder
Cladodontomorphi (Ginter et al., 2010). Schaeer and Williams
(1977) suggested that ctenacanths were most closely related
to euselachian sharks based on the presence of deeply rooted
dorsal spines, a cross section of the dorsal spine resembling
neoselachians, and a tribasal articulation of the pectoral n.
Lastly, neurocranial and mandibular arch information suggested
that ctenacanths may have had closer ties to xenacanths with
a close association of a chondrichthyan branch that included
xenacanths, ctenacanths, and symmorriids that was stem to a
crown chondrichthyan group that included holocephalans and
euselachians (Schaer, 1981; Maisey, 2005; Janvier and Pradel,
2016).
To test the relationship of Dracopristis homanorum
within Chondrichthyes and the validity of Ctenacanthiformes
as a natural group within Chondrichthyes, 49 to 56 taxa were
used for a cladistic analysis based on a matrix adapted from
Grogan and Lund (2008) (Fig. 12). Excluding Dracopristis,
other proposed “ctenacanth” taxa used include Ctenacanthus,
Cladodus, Cladodoides, Goodrichthys, Heslerodus, Glencartius,
“Tamiobatis” (data from CMNH 9820), a unnamed possible
ctenacanth from Bear Gulch (CM 46006, Hodnett et al., 2016)
and Bandringa. All characters were treated as unordered and
unweighted. The matrix initially ran 49 taxa, which of the
proposed “ctenacanths” consisted only of Ctenacanthus from
the Upper Devonian Cleveland Shale (data from AMNH 189,
CMNH 6219, 7852, 9440, and 9450), Sphenacanthus (data
from Dick, 1998 and Zangerl, 1981) and Bandringa (data from
Sallan and Coates, 2014). Settings for the analysis used New
Technology Search using Sectional Search, Ratchet, Drift,
and Tree fusing active. The rst cladistic analysis yielded ve
trees with tree lengths of 768. All ve trees showed a node
with Ctenacanthus and Dracopristis as sister taxa. Bandringa,
previously referred to as a ctenacanth (Zangerl, 1969, 1981),
was recovered well within Euselachii within a node that contains
Surcaudalus + Tristychius + Sphenacanthus (Fig. 12A). This
node supports a relationship previously proposed by Sallan
and Coates (2014). This node of Ctenacanthus + Dracropristis
shared a sister relationship with 11 taxa that formed Euselachii.
This larger clade, in turn, shows a sister relationship to three
taxa (Diplodoselache + Orthacanthus + Triodus) that form
Xenacanthimorpha. Variation from within the ve trees was
seen within Euselachii, with Hybodontiformes (Gansuselache +
Onychoselache + Hamiltonichthys) being the most stable node.
A second analysis was run with the same settings as
noted above, this time with the addition of the other proposed
ctenacanths (Ginter et al., 2010) (Fig. 12B). This analysis
retained a single tree with a tree length of 785. This tree shows
nine taxa--Cladodoides, Goodrichthys, Cladodus, Ctenacanthus,
CM 46006 (the Bear Gulch taxon, Hodnett et al., 2016), CMNH
9820 (“Tamiobatis,” Williams, 1998), Dracopristis, Heslerodus,
and Glencartius--sharing a monophyletic node with a sister
relationship to the Euselachii, supporting Ctenacanthiformes as a
natural group. Within this Ctenacanthiformes node, Dracropristis
holds a sister relationship with a node consisting of Glencartius
+ Heslerodus. This node of Dracopristis + Glencartius +
Heslerodus holds a sister relationship with the node of CM 46006
408
FIGURE 11. Cladistic analysis of Chondrichthyes. A, Strict consensus of ve trees of 49 taxa with a tree length of 768 showing
Dracopristis homanorum and Ctenacanthus as sister taxa within Ctenacanthiformes (bold node); B, Strict consensus of two trees
of 56 taxa with a tree length of 785 showing Dracopristis homanorum and nine other taxa forming Ctenacanthiformes (bold node).
+ CMNH 9820. Ctenacanthus holds a basal sister relationship
to this node group. Below this node, Cladodus + Goodrichthys
form a basal sister node. Cladodoides holds the most basal node
for the Ctenacanthiformes. This second analysis also supports
a sister relationship of Ctenacanthiformes and Euselachii,
while, in turn, this larger clade has a sister relationship with
Xenacanthimorpha. From both analyses the synapomorphies for
Ctenacanthiformes can be dened as elasmobranch sharks with
elongated postorbital region, dorsal otic ridges that originate
anterior to the posterior margin of the postorbital process,
laterally projecting otic processes, anterodorsal process present
on the otic process of the palatoquadrate, and with basolabial
and orolingual projections wider than the median cusp in teeth
that have enameloid connecting between cusps.
In both analyses, the symmoriid/stethacanthoid group
of chondrichthyans (Cobelodus + Stethacanthus + Falcatus
+ Damocles) together with Cladoselache, Squatinactis,
Thrinacoselache, and Doliodus were recovered as basal sister
members of the Xenacanthimorpha + Ctenacanthiformes
+ Euselachii node forming the Elasmobrachii, with the
Symmoriiformes the most basal node of the elasmobranch
chondrichthyans. The results of both analyses have several
implications. First, the relationship scheme of Cladodontomorphi
as dened by Ginter et al. (2010) would be paraphyletic
without the inclusion of Euselachii, Xenacanthimorpha, and
the Phoebodontiformes (i.e., Thrinacoselache). Second, this
analysis supports the sister relationship of Ctenacanthiformes
with Euselachii, with this node supported by the rst and second
dorsal ns with spines that are deeply xed on a basal cartilage
with supporting n radials, and a tribasal articulation of the
pectoral n to the scapulocoracoid, as originally suggested by
Schaer and Williams (1977). Third, contra Janvier and Pradel
(2016), both cladistic analyses suggest that ctenacanths, and
perhaps xenacanths, are closer to the crown euselachians than
basal stem chondrichthyans such as the symmoriids, Doliodus,
Squatinactis, Cladoselache, and Thrinacoselache, or a basal
elasmobranch node. Coates et al. (2017, 2018) showed a similar
placement of Xenacanthimorpha and “ctenacanths” in a stem
relationship to crown elasmobranchs/euselachians. Our analysis
also suggests that Symmorriiformes is retained as the most basal
stem elasmobranchs, contra Coates et al. (2017, 2018).
DISCUSSION
Diversity of Pennsylvanian Ctenacanthiforms
Dracopristis homanorum is a new ctenacanth taxon from
the Pennsylvanian, one which provides a wealth of information
due to the extent of endoskeletal preservation. Previously,
Pennsylvanian ctenacanths were only represented by Heslerodus
and Glikmanius. Beyond teeth and spines, Heslerodus is known
from cranial and postcranial material (Williams, 1985; Ginter,
2005; Ginter et al., 2005 and 2010). Heslerodus divergens is a
small ctenacanth taxon best known from the black shale units of
Indiana and Nebraska that include disarticulated skeletons and
the anterior portion of a partially complete individual (Williams,
1985; Stahl, 1988). Teeth of H. divergens are well represented
in the Pennsylvanian (Williams, 1985; Ginter et al., 2010) with
records extending into the Permain (Hodnett et al, 2012; Ivanov
et al., 2015).
Glikmanius, extending from the latest Mississippian to the
early Permian, is principally represented by teeth, and is known
from three species (Ginter et al., 2005, 2010; Hodnett et al.,
2012; Koot et al., 2013). Maisey et al. (2017) recently described
409
the fragmentary remnants of two very large ctenacanthiform
neurocrania from the latest Pennsylvanian (Virgilian) Finis
Shale Member of the Graham Formation in Jack County Texas.
Noting that large G. occidentalis have been recovered from this
deposit, Maisey, et al. (2017) posited these could belong to the
same taxon or another closely related one and documented that
at least one Pennsylvanian ctenacanthiform achieved a length of
7 meters. The articulated material of Dracopristis homanorum
corroborates and extends this record of a large sized ctenacanth,
as does the Permian Kaibabvenator swiftae, which had teeth
equal or greater in size to the Finis Shale Glikmanius teeth
(Hodnett et al., 2012).
The morphological features of the skeleton and soft tissue
preservation of Dracopristis homanorum (Fig. 11) oer some
clues in terms of its ecological placement at KBQ. The large
aplesodic pectoral ns have been attributed to extant sharks
that tend to be slow-cruising pelagic and benthic sharks that use
this pectoral n type for accelerating or maneuvering (Wilga
and Lauder, 2004). Other ctenacanths such as Ctenacanthus
concinnus, Glencartius, and CM 46006 have smaller plesodic
pectoral ns, which implies adaptations for fast swimming
pelagic sharks (Wilga and Lauder, 2004). Compagno (1990)
proposed various ecomorphological trophic categories for
extant and extinct chondrichthyans. Under Compagno’s (1990)
criteria, Ctenacanthus concinnus, Glencartius, and CM 46006
had smaller dorsal ns and smaller plesodic pectoral ns,
suggesting these taxa may have had a generalized eurytrophic
littoral ecomorphotype. Dracopristis may have been a more
specialized benthic or shallow pelagic shark. Dracopristis could
mark the rst appearance of a benthic specialized ctenacanth
within Ctenacanthiformes, but a more detailed ecomorphological
prole is needed for the ctenacanthiforms to evaluate this
possibility.
The KBQ locality represents an estuarine /lagoon deposition
with brackish shallow waters. Evidence of larger sharks at
KBQ, like Glikmanius occidentalis, is presently restricted to
teeth, and it’s been suggested that Glikmanius may have been
more of a marine visitor the KBQ lagoon rather than a resident
(Williams and Lucas, 2013). Dracopristis may have been a
coastal estuary specialist, similar in regard to some euryhaline
elasmobranchs such as the bull shark (Carcharhinus leucas) or
the common sawsh (Pristis pristis). There are few fossil sites
outside of KBQ that represent a similar euryhaline environment.
Euryhaline deposits are seen at the Pennsylvanian Hamilton
Quarry in Kansas and the Mazon Creek localities of Illinois,
though neither locality currently has evidence of large bodied
chondrichthyans (Mapes and Mapes, 1988; Shabica and Hay,
1997).
CONCLUSIONS
What is a “Ctenacanth?” Answered
Our analysis of Dracopristis homanorum and its
comparison with other chondrichthyan taxa suggest that
Dracopristis, Ctenacanthus, Cladodus, Heslerodus,
Goodrichthyes, Glencartius, and a “Tamiobatis” clade
(CMNH 9280 and CM 46006) form a monophyletic group
within Chondrichthyes that would be dened as the order
Ctenacanthiformes (Glikman, 1964). The synapomorphies for
Ctenacanthiformes include dosal otic ridge originating anterior
to the posterior margin of the post orbital process, laterally
projecting otic process, anterodorsal process on the otic process
of the palatoquadrate, a well-developed dorsal crest that extends
from the anterdorsal margin of the otic process to the quadrate,
a well-developed ventral ridge on the lateral margin of the
Meckel’s cartilage that extends two thirds the length of the
jaw, and teeth with a basolabial depression and basolabial and
orolingual projections wider than the median cusp. These dental
traits would also include tooth-based taxa such as Glikmanius,
Kaibabvenator, Saivodus, Neosaivodus, and Nanoskalmae to
be members of the Ctenacanthiformes as well (sensu Ginter et
al, 2010; Hodnett et al., 2012). The inclusion of Cladodoides
within the Ctenacanthiformes, even though it lacks otic
processes and the anterodorsal process of the otic process of the
palatoquadrate, stems from dental similarities, the possibility of
a dorsal otic ridge originating anterior of the posterior margin of
the post orbital process, and having an elongated ventral lateral
crest on the Meckel’s cartilage extending two thirds the length
of the jaw. Our cladistic analysis suggests this monophyletic
group shares a sister relationship with Euselachii, and in turn
Euselachii + Ctenacanthiformes shares a sister relationship with
Xenacanthimorpha. This relationship arrangement suggests
that Cladodontomorphi as proposed by Ginter et al., (2010)
FIGURE 12. Reconstruction of Dracopristis homanorum. Scale bar equals 1 meter.
410
is paraphyletic without the inclusion of Xenacanthimorpha or
Euselachii, and ctenacanths are not stem chondrichthyans as
proposed by Janvier and Pradel (2016).
The interrelationships of Ctenacanthiformes is still a work
in progress. Ginter et al. (2010) previously placed Ctenacanthus,
Cladodoides, Tamiobatis, Cladodus, and Glikmanius in
Ctenacanthidae (Dean, 1909) largely based on spine similarities.
Heslerodus, Glencartius, Goodrichthys, and Saivodus were
placed by Ginter et al. (2010) as Ctenacanthiformes incertae
sedis. Maisey (2010) established Heslerodidae for Heslerodus
and the n spine taxa Avonacanthus and Bythiacanthus based
on similarities of n spine morphologies. The Hodnett et al.
(2012) cladistic analysis of ctenacanth teeth suggested that
taxa such as Ctenacanthus and Cladodoides formed their
own basal clades within Ctenacanthiformes, Cladodus +
Goodrichthys formed a clade, and Glikmanius + Heslerodus
+ Kaibabvenator + Nanoskalmae formed one clade that has a
sister relationship with a clade containing “Tamiobatis” (CMNH
9280) + Saivodus + Neosaivodus. Our current cladistic analysis
of Ctenacanthiformes (Fig. 12B) showed a similar relationship
scheme as presented in Hodnett et al (2012). Dracopristis was
recovered in a clade containing Heslerodus + Glencartius,
which has a sister relationship with the clade CMNH 9280
(“Tamiobatis”) and CM 46006 (Bear Gulch taxon). The primary
dierence between our current analysis and Hodnett et al (2012)
was that Ctenacanthus is placed more closely related to the
previous two clades, whereas Cladodus + Goodrichthys is a
more basal clade. Cladodoides still maintains a stem position
within Ctenacanthiformes in both our analysis and Hodnett et
al. (2012).
From both sets of data there is a suggestion that there
are at least four to ve families or superfamily levels within
Ctenacanthiformes that include Cladodoides as an unnamed stem
family, Ctenacanthus as a representative of Ctenacanthidae and
Cladodus + Goodrichthys, as either another unnamed family/
superfamily, or both placed within Ctenacanthidae. Heslerodus
and other members of the Heslerodidae are probably placed
into an unnamed superfamily that also contains Dracopristis,
Glikmanius, Glencartius, Kaibabvenator, and Nanoskalmae;
for which the familial levels still need to be dened. This group
may have a sister relationship to a family or superfamily that
contains “Tamiobatis” (CMNH 9820), Saivodus, Neosaivodus,
and CM 46006 (the Bear Gulch taxon). Key to formally dening
these groups is the reanalysis of the specimens pertaining to
Glencartius and Goodrichthys eskdalensis, both of which under
new computed tomography or surface scanning techniques
could yield a wealth of more detailed anatomical data.
The Kinney Brick Quarry Ctenacanths
The ctenacanth sharks at KBQ represent the largest
vertebrates in the KBQ assemblage. The teeth of Glikmanius
occidentalis suggest this taxon is the larger of the two ctenacanth
species, estimated at about 3-4 meters in length based on tooth
dimensions. Due to the rarity of the teeth of G. occidentalis
this taxon probably did not occur regularly within the estuary/
lagoon of KBQ (Williams and Lucas, 2013). Dracopristis
homanorum is a new genus and species of ctenacanth adapted
to the shallow estuary/lagoon system of KBQ, probably as
a slow moving ambush predator, using its large spines as a
deterrent to larger predators such as Glikmanius and possibly
eugenodont chondrichthyans like Campyloprion, also known
from the Tinajas Member of the Atrasado Formation (Itano
and Lucas, 2016, 2018). Ctenacanths are a rarer component
to the chondrichthyan assemblage at KBQ. A Cobelodus-like
symmoriid taxon is a smaller (approximately less than a meter
in length), more common chondrichthyan at KBQ (Hodnett and
Lucas, 2015). Other chondrichthyans at KBQ include a small
hybodont, a xenacanth, a petalodont, and a holocephalan (Hodnett
and Lucas, 2015). Overall, chondrichthyans are rare compared
to the much more common Acanthodes and actinopterygians
at KBQ, all prime prey for the KBQ ctenacanths (Hodnett and
Lucas, 2015).
ACKNOWLEDGMENTS
We greatly thank Ralph and Jeanette Homan for allowing
NMMNHS to continue eld work at the KBQ over the years and
their dedication to preserving the fossils found at the KBQ for
future generations to come. We are indebted to Rust Presbyterian
Medical Center for generously allowing us to use their time and
CT Scanning facility for this project. We also thank A. Cantrell
and L. Rinehart, who helped extract the Dracopristis holotype
from KBQ. Two annonymus reviewers provided helpful
comments and edits for this paper. Thanks also to A. McGee, L.
Hall, and M. Ryan of CMNH, who hosted JPH during his visit
to work on Cleveland Shale sharks. We would like to thank J.
Maisey, M. Friedman, H.-P. Schultze, S. Williams, A. Ivanov,
W. Itano, J. Fischer, and J. Schneider for their conversations and
input that helped enrich this project.
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413
APPENDIX 1. Description of characters and states used for
phylogenetic analysis
[0] Mineralized enoskeletal tissue, (0) perichondral bone, (1)
prismatic calcied cartilage, (2) supercially continuous, (3)
spheritic tesserae.
[1] Male frontal clasper, (0) absent, (1) median, (2) median
extremely elongate, (3) single pair, (4) multiple pairs.
[2] Extended neurocranial rostrum, (0) absent, (1) open
skeletogenous rod supports, (2) continuous ventral trough/keel,
(3) entirely enclosed.
[3] Anterior braincase opening, (0) absent, (1) large/precerebral
fontanelle, (2) closed/small opening.
[4] Rostrum: basal plane, (0) greater than 180 degrees, (1) 180
degrees.
[5] Ethmoid % of neurocranium, (0) <25%, (1) 25-40%, (2) 40-
50%, (3) >50%.
[6] Orbital % of neurocranium, (0) 25-46%, (1) <35%, (2) >46%.
[7] Postorbital % of neurocranium, (0) 25-40%, (1) 15-25%, (2)
>40%, (3) <15%.
[8] Anterior ventral braincase (cross-section), (0) narrow
v-shape, (1) platybasic, narrow, (2) platybasic, wide.
[9] Posterior ventral braincase (cross-section), (0) narrow
v-shape, (1) narrow shelf, (2) wide shelf.
[10] Nasal capsule condition, (0) no skeletonized/mineralized
tissue, (1) in-line with otic capsules, (2) shift medial to meet in
midline, (3) shift to distal (lateral) position.
[11] Supraorbital cartilage, (0) absent, (1) present, (2) present
and distally expanded.
[12] Orbital condition, (0) not medially proximate, (1) medially
conuent or nearly so.
[13] Postorbital process, (0) small protuberance dorsally, (1)
ventral directed postorbital process, (2) postorbital wall, (3)
lateral projection dorsally, (4) caudally oblique lateral projection,
(5) none.
[14] Otic region length, (0) approximately same length of otic
capsule, (1) greater than otic capsule length.
[15] Endolymphatic fossa, (0) absent, (1) elongate, (2) ovate, (3)
small pored opening.
[16] Dorsal otic ridge, (0) absent, (1) originates anterior to the
rear postorbital margin, (2) originates at or beyond postorbital
process.
[17] Otic process, (0) absent, (1) laterally directed, (2) obliquely
caudal directed.
[18] Occipital contribution to postorbital cranium, (0) < 10%,
(1) 20-50%, (2) 75-100 %
[19] Extravisceral cephalic cartilages, (0) pre-mandibular
feeding elements, (1) prominent labials, (2) few/reduced labials,
(3) large posterior, (4) none.
[20] Anterior extravisveral cartilage function, (0) oral hood, (1)
primary biting, (2) outer board mouth rim, (3) prehensile lip
support, (4) lips supplemental to jaws, (5) bones form external
jaw arcade, (6) absent
[21] Principle skeletal oral margin, (0) premandibular/labial
complex, (1) premaxilla, maxilla, and dentary, (2) supragnathals
and infragnathals, (3) palatoquadrate and Meckel’s cartilages,
(4) palatoquadrate and Meckel’s cartilage ossications.
[22] Palatoquadrate anteriad, (0) seprate, (1) parallel
(parasymphysial extension), (2) median symphasis, (3) ends at
basal articulation.
[23] Palatoquadrate-otic (pterygoid) process shape, (0) slight/
underdeveloped, (1) dorsally recurved, (2) posteriorly extended,
(3) dorsally expanded.
[24] Palatoquadrate: ethmoid association, (0) none, (1)
ligamentous bound ethmoid ligament, (2) jointed with ethmoid
recess.
[25] Basal Palatoquadrate articulation, (0) none, (1)
basitrabecular, (2) basitrabecular & postorbital process, (3)
basipterygoid, (4) orbital process & ligament, (5) fused.
[26] Palatoquadrate-basitrabecular articulation, (0) present, (1)
fused, (2) absent.
[27] Palatoquadrate-postorbital articulation, (0) absent, (1)
under postorbital process, (2) on posterior side of postorbital
process, (3) posterior to postorbital process.
[28] Basitrabecular process attitude, (0) in line with post orbit
edge/postorbital, (1) ared ventrolateral to postorbital, (2) ared
antero-ventrolaterally, (3) absent.
[29] Basitrabecular-palatoquadrate articulation, (0) postorbital,
(1) orbital, (2) antorbital, (3) absent.
[30] Anteriormost aspect of pterygoidal otic articulation, (0)
absent, (1) lateral cranial fossa, (2) anteriorly directed transverse
process, (3) transverse process transitions into palatoquadrate
dorsolateral ridge.
[31] Rectangular pterygoidal articular facet, (0) absent, (1)
present.
[32] Chondrocranial construction (adult), (0) > 2moieties, (1) 2
moieties, (2) continuous vault.
[33] Occipital joint/ssure, (0) ssure continuous with ventral
otic ssure, (1) ssure continuous with ventral occipital ssure,
(2) dorsally open, (3) none/fused.
[34] Occipital moiety, (0) dorsal occipital + separate ventral
elements, (1) dorsal occipital and ventral basioccipital, (2)
separate dorsal, fused ventral elements, (3) single (D+V) separate
unit, (4) occipital fused to otic moiety, (5) separate parachordal.
[35] ethmo-sphenoid joint/ssure, (0) open ssure, (1) mobile
joint, (2) none.
[36] Suspensorium, (0) autodiastyly, (1) hyostyly, (2) amphistyly,
(3) holostyly, (4) met-hyostyly.
[37] Suspensorial hyomandibular, (0) none/absent, (1) direct
articulation with postorbital process, (2) direct articulation
poteroventral otic, (3) direct articulation poterolateral otic, (4)
direct articulation poterodorsal otic, (5) direct articulation to
near occipital, (6) other.
[38] Hyomandibular condition, (0) none/absent, (1) stout
rectangular block approximately vertical, (2) blade-like element
angled posteriorly, (3) blade-like element nearly vertical, (4)
blade-like element angled anteriorly, (5) other.
[39] Meckel’s symphysis, (0) none/absent, (1) mobile symphysis,
(2) symphysial fused to Meckel’s cartilages, (3) ligamentous
mandibular association, (4) midline fusion of Meckel’s.
[40] Level of Meckel’s-quadrate articulation, (0) postorbital, (1)
orbital, (2) preorbital.
[41] Mandibular mineralization, (0) bone, (1) prismatic calcied
cartilage, (2) solid brocartilage, (3) other mineralization.
[42] Upper parasymphysial/cartilage(s), (0) multiple, (1) small,
(2) anteriorly expanded, (3) absent.
[43] Lower symphysial elements(s), (0) multiple, (1) present
between mandibles, (2) extended anteriad, (3) absent.
414
[44] Gill Openings, (0) single soft opercular valve, (1) separate
gill openings, (2) bony opercular valve.
[45] Epal hyoid, (0) opercular support, (1) mandibular arch
support.
[46] Buccopharyngeal/palatal denticles, (0) simple to compound
odontodes, (1) absent.
[47] Ventral hyoid and branchials, (0) normal, (1) anteriorly
elongate.
[48] Branchial basket, (0) subotic to postcranial, (1) subcranial,
(2) principally postcranial.
[49] Tooth row/jaw length, (0) absent/na, (1) >50%, (2) <40%.
[50] Anterior extragnathic dentition, (0) absent/na, (1) ethmoid/
between palatoquadrates, (2) rostral, (3) bony premaxilla.
[51] Tooth/jaw association, (0) absent/na, (1) individual tooth
wells per family, both jaws, (2) all tooth families in single sulcus
along jaws, (3) individual tooth wells per family, upper jaw only,
(4) teeth follow jaw margin.
[52] In line cusp relationship, (0) absent/na, (1) unicuspid, (2)
parallel, (3) highly divergent from base, (4) divergent twisted.
[53] Relative cusp sizes, (0) absent/na, (1) unicuspid, (2) all
cusps equal, (3) laterals largest/central small or absent, (4)
central largest/others lower.
[54] Cusp alignment relative to jaw axis, (0) absent/na, (1)
parallel, (2) lingual concave, (3) twisted contorted alignment,
(4) other.
[55] Cusp condition, (0) absent/na, (1) unicuspid, (2) multiple in-
line, (3) descending from central, (4) cusps reduced/suppressed,
(5) ridge descending from central.
[56] Cusp cross section, (0) absent/na, (1) rounded, (2) reduced/
suppressed, (3) compressed blade-like.
[57] Cusp numbers, (0) absent/na, (1) unicuspid, (2) bicuspid,
(3) tricuspid, (4) >3, (5) variable.
[58] Crown/rooth height, (0) absent/na, (1) equal/subequal, (2)
very high crowned, (3) brachydont, (4) variable.
[59] Enamel cusp separation, (0) absent/na, (1) distinctly separate
on base, (2) cusps conuent, (3) cusps reduced/suppressed.
[60] Functional jaw tooth families, (0) absent/na, (1) 1-2 per
family, (2) pavement occlusion, (3) teeth & tooth plates, (4)
tooth plates only.
[61] Tooth shapes on jaw, (0) absent/na, (1) homodont, (2)
monognathic heterodonty, (3) dignathic heterodonty, (4) teeth
and tooth plates, (5) plates alone.
[62] Lower symphysial family, (0) absent/na, (1) generalized,
(2) prominent, (3) whorl, (4) fused plate, (5) paired whorl, (6)
multiple families
[63] Upper parasymphysial family, (0) absent/na, (1) generalized,
(2) prominent, (3) whorl, (4) fused plate.
[64] Crown base, (0) absent/na, (1) generalized, (2) lingual heel,
(3) lingual, labial ridges, (4) basin and ridges.
[65] Crown lingual/labial buttresses, (0) absent/na, (1)
crenellated, (2) buttressed.
[66] Tooth root vascular pattern, (0) absent/na, (1) few
nutrient foramina aborally and lingually, (2) multiple nutrient
foramina labiolingually and aborally, (3) few nutriend foramina
labiolingually, (4) apical
[67] Tooth root length, (0) absent/na, (1) short below crown, (2)
long below crown, (3) extended lingual, (4) fused in family.
[68] Root direction, (0) absent/na, (1) straight below and wide
as crown, (2) straight below and narrow than crown, (3) aboral/
lingual s-shape, (4) lingual shelf, (5) proximo-distally arched,
(6) separated by neck, contorted.
[69] Basolabial/orolingual root projection widths, (0) absent/na,
(1) ridges narrower than primary cusp(s), (2) ridges wider than
primary cusp(s).
[70] Basolabial root projection structure, (0) absent/na, (1)
basolabial ridge/peg single, (2) basolabial ridge/peg divided.
[71] Orolingual rooth projection structure, (0) absent/na, (1)
orolingual ridge single, (2) orolingual ridge divided.
[72] Basolabial depression, (0) absent/na, (1) shallow, (2)
moderate, (3) deep.
[73] Intermediate cusps structure, (0) absent/na. (1) shorter than
lateral cusps, (2) taller than lateral cusps.
[74] Intermediate cusp number, (0) absent/na, (1) 1 to 2, (2)
greater than 2.
[75] Lateral cusps, (0) absent/na, (1) taller than median, (2)
shorter than median.
[76] Accessory labial cusps, (0) absent/na, (1) present, (2)
variable.
[77] Enameloid layers, (0) absent/na, (1) radial crystallite, (2)
complex.
[78] Orthodentine, (0) absent/na, (1) present.
[79] Osteodentine, (0) absent/na, (1) present.
[80] Paired, upper dental positions, (0) absent/na, (1) > 3(teeth),
(2) 2 anterior, 1 posterior, (3) 1 anterior, 1 posterior, (4) 1
posterior.
[81] Paired, anterior lowers, (0) absent/na, (1) >3 (teeth), (2) 2
anterior, (3) 1 anterior, (4) absent.
[82] Middle, lower condition, (0) absent/na, (1) tooth, (2) whorl,
(3) plate.
[83] Posterior dental histology, (0) absent/na, (1) coronal tooth
tissues, (2) tritoral dentine, (3) pleromin tritors, (4) other.
[84] Anterior and middle dental surfaces, (0) absent/na, (1)
coronal tooth tissues, (2) limited tritors, (3) complete coverage
of tritors.
[85] Anterior dental histology, (0) absent/na, (1) coronal tooth
tissues, (2) tritoral dentine, (3) pleromin tritors, (4) bone, no
tritor.
[86] scale type, (0) placoid, (1) zonal growth, (2) fused placoid,
(3) thin radially denticulate scales, (4) “Petrodus”-like thick
base scales, (5) absent, (6) ganoid.
[87] Head scale coverage, (0) generalized, (1) both generalized
and specialized, (2) specialized areas only, (3) absent, (4) cranial
bones.
[88] Heads scale modications, (0) generalized, (1) enlarged
scales/spines, (2) plates, (3) cranial bones, (4) absent.
[89] Head dermal bones, (0) absent, (1) present
[90] Head lateral lines scales, (0) small, simple, oriented, (1)
thin rings, (2) bony plates, (3) canal(s) enclosed in plates, (4)
absent
[91] Ethmo-rostral scales, (0) generalized, (1) spikes, (2)
enlarged denticles, (3) few plates, (absent)
[92] Supraorbital scales, (0) generalized, (1) enlarged scales/
spines, (2) plates, (3) absent, (4) cranial bones.
[93] Otic Scales, (0) generalized, (1) enlarged scales/ spines, (2)
415
plates, (3) absent, (4) cranial bones.
[94] Occipital scales, (0) generalized, (1) enlarged scales/spines,
(2) compound plates & spines, (3) absent, (4) cranial bones.
[95] Mandibular squamation, (0) generalized, (1) posterior
specialization, (2) longitudinal specialization (plates), (3)
absent, (4) cranial bones
[96] Posterior mandibular scales, (0) generalized, (1) small
sharp spine, (2) broad spine, (3) buttressed plate, (4) absent
[97] Basitrabecular rim scales, (0) generalized, (1) few large
denticles. (2) plate, (3) plate and spine, (4) absent.
[98] Body scales, (0) generalized, (1) generalized and specialized
areas, (2) only specialized areas, (3) absent.
[99] Enlarged paired dorsal body scales, (0) generalized, (1) 1st
dorsal to caudal n, (2) between ns only, (3) past 2nd dorsal,
(4) absent.
[100] Dorsal n squamation, (0) complete covering, (1) crest of
n only, (2) upon radials, (3) absent.
[101] Squamation/Sex, (0) monomorphic, (1) sexually dimorphic
[102] lateral line scales of body, (0) small, simple, oriented, (1)
rings, (2) canal through scale, (3) none
[103] scapular process, (0) skeletal link to neurocranium, (1)
adjacent to neurocranium, (2) distand from neurocranium.
[104] Scapulocoracoid posterior margin, (0) simple/straight, (1)
rectangular processes&/or notches.
[105] dorsal scapula, (0) scapular margin simple, (1) with
anteriorly directed suprascapula, (2) with posteriorly directed
suprascapula.
[106] Pectoral n position, (0) ventrolateral, (1) mid-ank, (2)
nape of neck.
[107] Pectoral girdle, (0) principally endoskeletal, (1) principally
exoskeletal.
[108] Coracoid-procoracoid length, (0) normal, (1) extended
anteriorly, (2) truncated anteriorly.
[109] Procoracoid, (0) paired, anteriorly directed, (1) paired,
posteriorly directed, (2) paired, medially directed, (3) fused,
median, (4) absent.
[110] Proximal n elements: girdle, (0) on scapular ridge and
glenoid surface, (1) on glenoid surface alone, (2) on glenoid
& metapterygium, (3) on scapular ridge glenoid surface &
metapterygium, (4) other.
[111] Pectoral n, (0) uniserial, (1) partially biserial, (2) entirely
biserial.
[112] Pectoral n base, (0) multibasal eurybasal, (1) unibasal
stenobasal, (2) tribasal, (3) spine.
[113] Pectoral post-metapterygial axis, (0) none/absent, (1) 1-4
elements, (2) 4-8 small elements, (3) >9 elements, (4) axsis but
no metapterygium.
[114] Pectoral n element series, (0) proximal series, (1)
proximal and distal series, (2) proximal, intermediate, & distal
series, (3) spine only
[115] Pectoral leading edge denticles, (0) na, (1) many, small,
(2) few rows, large, (3) single large row.
[116] Pelvic girdle mineralization, (0) bone, (1) supercial
calcied cartilage, (2) solid 3-dimensional, (3) absent.
[117] Pelvic dorsal process, (0) absent, (1) short, (2) tall
[118] Pelvic basipterygium, (0) minor or absent, (1) elongate,
(2) triangular to rounded, (3) spine alone
[119] Fertilization, (0) without claspers in males, (1) pelvic
claspers in males
[120] Pelvic radials, (0) majority on girdle, (1) ~50% on
basipterygium, (2) majority on basipterygium, (3) spine alone.
[121] Pelvic girdles, (0) separate across midline, (1)
puboischiadic bar in males, (2) puboischiadic bar in both sexes.
[122] Prepelvic tenaculum. (0) absent, (1) jointed, anterior edge
of n, (2) jointed at anterior edge of girdle, (3) non-jointed
anterior edge of girdle.
[123] Prepelvic tenaculum squamation, (0) absent/na, (1)
multiple denticles, (2) enlarged denticles hooks &/or spines.
[124] Anal n and/or anal plate, (0) absent, (1) present.
[125] Dorsal n number, (0) two ns, (1) one n.
[126] Dorsal spines, (0) anterior dorsal n only, (1) spines on
both dorsal ns, (2) no spines.
[127] Dorsal spine lateral surface ornamentation, (0) none/
absent, (1) denticulated rows, (2) smooth longitudinal costae,
(3) smooth enamel only.
[128] Denticles on anterior &/or posterior dorsal spine margin,
(0) paired rows posteriorly directed, (1) none, (2) posteriorly
directed in single or alternating rows, (3) paired rows laterally
directed, (4) no spines, (5) anterior rows.
[129] Anterior Dorsal n, (0) large, (1) small ap, (2) absent,
(3) rod.
[130] Anterior dorsal n and/or spine support, (0) basal plate/
radials. (1) synarcuum, (2) on head, (3) on shoulder girdle, (4)
absent.
[131] Anterior dorsal spine, (0) deeply xed, (1) long mobile,
(2) supercial insertion, (3) absent.
[132] Anterior dorsal spine presence, (0) found in both sexes, (1)
absent in both sexes, (2) sexually dimorphic.
[133] Anterior dorsal n/spine development, (0) at birth, (1) at
puberty, (2) absent
[134] Anterior dorsal spine shape, (0) posteriorly directed,
narrow, (1) triangular, (2) forward curved, (3) absent.
[135] Anterior dorsal spine enameloid/dentine, (0) present, (1)
absent, (2) no spine.
[136] Posterior Dorsal Fin, (0) short, (1) elongate, (2) absent
[137] Posterior dorsal n base, (0) all radials, (1) basal plate &
radials, (2) basal plate, (3) other, (4) absent.
[138] Posterior dorsal spine, (0) absent, (1) supercial insertion,
(2) deeply xed.
[139] Caudal n, (0) heterocercal, (1) extended heterocercal, (2)
abbreviated heterocercal, (3) homocercal, (4) diphycercal.
[140] Caudal endoskeleton, (0) serial hypochordal, (1) epichordal
component, (2) epichordal fusions/expansions, (3) epichordal &
hypochordal fusions/expansions, (4) homocercal.
[141] notochordal calcication, (0) uncalcied, (1) chordacentra,
(2) complete centra
[142] vertebral arcual mineralization, (0) uncalcied, (1)
regionalized, (2) entire column.
[143] ribs, (0) absent, (1) present.
416
APPENDIX 2. Character-taxon matrix used for phylogenetic analysis.
outgroup 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0
Onychodus 0 0 0 0 0 0 0 0 0 0 0 0 0
5 0 0 0 0 2 0 5 1 3 0 0 3 2 0
5 3 0 0 0 0 1 1 4 0 0 0 0 0 0
3 2 0 0 0 0 1 3 4 1 1 1 1 1 1
0 0 0 1 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 1 1 0 0 0 0 0 0 0 7 4
3 1 4 4 4 4 4 4 4 4 0 4 3 0 0
0 0 0 0 1 0 4 4 0 0 4 3 0 0 0
0 0 0 0 0 0 1 1 2 0 4 0 4 3 1
2 3 2 1 0 0 4 0 1 2 0
Kalops 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 2 0 5 1 3 0 0 0 2 0
5 3 0 0 0 0 5 0 4 0 0 0 0 0 0
3 2 0 0 0 0 1 3 4 1 1 1 1 1 1
0 0 0 1 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 1 1 0 0 0 0 0 0 0 7 4
3 1 4 4 4 4 4 4 4 4 0 4 3 0 0
0 0 0 0 1 0 4 4 0 0 0 3 0 0 0
0 0 0 0 0 0 1 1 2 0 4 0 4 3 1
2 3 2 0 0 0 0 0 1 2 0
Hadronector 0 0 0 0 0 0 0 0 0 0 0 0 0
5 0 0 0 0 2 0 5 1 3 0 0 3 2 0
5 3 0 0 0 0 1 1 4 0 0 0 0 0 0
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0 0 0 1 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 1 1 0 0 0 0 0 0 0 7 4
3 1 4 4 4 4 4 4 4 4 0 4 3 0 0
0 0 0 0 1 0 4 4 0 0 4 3 0 0 0
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0 0 0 0 0 0 0 5 2 3 0 0 0 2 0
5 3 0 0 0 1 0 0 4 0 0 0 0 0 0
3 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 6 4
3 1 3 4 4 4 4 4 4 4 3 4 3 0 0
0 0 0 0 0 0 4 4 0 0 0 0 0 1 0
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0 0 1 1 0 0 0 0 0 0 0 0 0 0 0
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0 0 0 4 3 3 3 3 4 4 0 0 3 0 0
1 0 0 0 1 0 4 4 0 3 0 4 0 0 0
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0 0 1 0 3 1 0 0 0 0 0
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3 1 1 0 ? 2 1 1 1 2 3 1 2 1 2
417
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0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
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3 1 1 0 1 2 2 2 1 4 3 3 3 1 3
2 1 1 2 0 0 0 0 1 3 6 0 0 0 0
0 0 1 0 2 1 1 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2 0 3 0 0 0 2 0 0 0 3 2 0 1 0
0 1 2 0 0 0 0 1 2 0 4 1 4 3 1
2 3 2 0 0 0 1 1 0 0 0
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0 2 1 0 0 0 0 0 0 0 0
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0 ? 0 0 1 4 6 3 2 1 2 2 2 2 0
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1 1 0 1 2 1 0 1 2 4 1 2 1 4 2
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0 0 0 0 0 0 0 0 0 4 4 1 1 0 2
0 0 0 0 1 0 0 0 0 2 0 0 1 0 0
1 0 0 0 0 0 1 0 0 1 2 3 2 2 0
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0 0 1 0 1 2 2 2 2 4 3 3 0 1 3
3 1 1 0 1 2 1 0 1 2 4 1 2 1 4
2 1 1 2 0 0 0 0 1 3 4 1 1 1 0
1 1 2 0 2 1 1 0 0 0 0 0 0 0 2
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2 0 0 0 0 1 0 0 0 0 2 0 0 1 0
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0 2 1 0 0 0 0 0 0 0 0
418
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0 0 1 0 1 2 2 2 2 4 3 3 0 1 3
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2 1 1 2 0 0 0 0 1 3 4 1 1 1 0
1 1 2 0 2 1 1 0 0 0 0 0 0 0 2
0 0 0 0 0 0 0 0 0 0 4 4 3 0 0
2 0 0 0 0 1 1 0 0 0 3 0 0 1 0
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2 3 2 1 0 0 0 0 0 0 0
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3 1 ? ? ? ? 4 6 3 ? 2 2 4 2 2
0 0 3 0 1 2 2 2 2 1 2 3 0 1 3
3 1 1 0 ? 2 2 ? 3 3 3 1 2 3 3
2 1 1 2 0 0 0 0 1 3 4 1 1 1 0
0 0 1 0 2 1 1 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2 0 2 0 0 1 0 2 0 3 1 2 0 1 0
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0 0 3 0 1 2 2 2 2 1 2 3 0 1 3
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2 1 1 2 0 0 0 0 1 3 4 1 1 1 0
0 0 1 0 2 1 1 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2 0 2 0 0 1 0 2 1 1 3 2 0 1 0
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0 0 1 2 0 0 1 2 1 2 0
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0 0 3 0 1 2 2 2 2 1 2 3 0 1 3
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2 1 1 2 0 0 0 0 1 3 4 1 1 1 0
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0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
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2 1 2 2 0 2 1 1 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0 0 0 0 0 0 0
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1 0 0 0 0 0 0 0 0 0 0 0 0 0 0
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2 2 1 2 0 0 0 0 1 3 4 2 2 2 3
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420
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3 1 1 0 0 2 1 0 2 1 1 1 4 1 1
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0 1 2 0 0 0 1 0 1 2 1 0 0 0 0
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3 1 1 0 0 2 1 0 2 1 1 1 1 2 1
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1 0 ? 0 0 ? 4 6 3 2 0 1 4 2 1
0 0 0 0 1 ? ? 2 1 3 1 3 0 1 3
3 1 1 0 ? 2 1 0 1 1 1 1 1 2 3
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0 0 2 0 2 1 1 0 0 0 0 0 0 0 0
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0 0 ? 0 1 ? ? 2 2 1 ? 3 0 1 3
3 1 1 0 ? 2 ? ? ? 1 1 1 1 3 1
1 2 1 2 0 0 0 0 2 3 4 0 0 0 0
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0 1 2 0 0 0 1 0 1 3 1 0 0 0 0
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421
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1 0 0 0 0 0 0 0 0 0 0 0 0 1 0
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3 1 1 0 1 1 4 6 3 2 1 2 4 2 2
0 0 2 0 1 ? ? 2 2 1 2 3 0 1 3
3 1 1 0 1 2 1 0 2 1 1 1 1 3 1
1 3 1 2 0 0 0 0 2 3 3 0 0 0 0
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0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2 0 0 0 0 1 4 2 0 ? ? 1 1 1 0
1 1 2 0 0 0 1 0 1 1 1 0 0 0 0
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1 0 3 0 0 1 2 6 3 2 0 1 4 2 1
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2 0 1 0 0 1 4 6 3 1 0 2 1 0 0
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2 3 1 2 3 3 3 1 3 2 3 0 0 0 0
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2 0 3 0 0 1 4 6 3 1 0 2 1 0 0
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2 0 0 1 0 0 1 0 ? 2 4 1 4 2 5
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422
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5 0 ? 0 0 1 2 6 3 1 3 0 5 1 0
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3 0 4 5 0 0 0 0 4 4 0 0 0 0 0
0 0 0 0 2 0 1 3 4 0 1 3 3 5 3
4 0 1 4 3 3 3 3 4 4 4 2 3 1 1
1 0 0 0 0 2 4 1 2 1 0 1 0 2 2
2 1 2 0 3 1 1 0 0 3 1 0 1 1 0
0 0 0 1 0 0 0 0 2 2 0
Echinochimeria 2 0 0 0 1 1 1 1 1 2 3 0 1
5 0 0 0 0 1 2 2 3 1 3 0 5 1 0
5 2 0 0 2 3 4 2 3 0 0 4 1 2 3
424
3 0 0 1 0 0 1 0 4 0 0 0 0 0 0
3 0 4 5 0 0 0 0 4 4 0 0 0 0 0
0 0 0 0 2 0 1 4 4 0 1 3 3 3 2
1 0 1 0 1 1 1 3 4 4 1 3 1 1 1
1 0 0 1 0 1 4 1 0 1 0 1 0 2 2
2 1 2 0 1 2 1 0 0 1 5 0 1 1 0
0 0 0 1 0 0 0 0 1 1 0
Metopacanthus 2 2 3 0 1 1 1 1 1 2 3 0 1
5 0 0 0 0 1 2 3 3 1 3 0 5 1 0
5 2 0 0 2 3 4 2 3 0 0 4 1 2 3
3 0 0 1 0 0 1 0 4 0 0 0 0 0 0
3 0 4 5 4 0 0 0 4 4 0 0 0 0 0
0 0 0 0 2 0 1 2 4 0 2 2 1 3 1
2 0 1 2 3 3 3 2 2 4 ? ? ? 0 1
1 0 0 0 0 0 4 1 1 1 0 1 0 ? 1
? ? ? ? 0 0 ? ? 0 1 0 0 1 1 0
0 0 0 ? ? 0 ? ? 2 2 0
Rhinochimera 2 1 1 0 1 1 1 1 1 2 3 0 1
5 0 0 0 0 1 1 3 3 1 3 0 5 1 0
5 2 0 0 2 3 4 2 3 0 0 4 1 2 3
3 0 0 1 0 0 1 0 4 0 0 0 0 0 0
3 0 4 5 0 0 0 0 4 4 0 0 0 0 0
0 0 0 0 2 0 1 3 4 0 1 3 3 5 3
4 0 1 4 3 3 3 3 4 4 4 4 3 0 1
1 0 0 0 0 0 4 1 1 1 0 1 0 2 2
2 1 2 0 3 1 0 0 0 3 1 0 1 1 0
0 0 0 1 0 0 1 0 2 2 0
Hydrolagus 2 1 1 0 1 1 1 1 1 2 3 0 1
5 0 0 0 0 1 1 3 3 1 3 0 5 1 0
5 2 0 0 2 3 4 2 3 0 0 4 1 2 3
3 0 0 1 0 0 1 0 4 0 0 0 0 0 0
3 0 4 5 0 0 0 0 4 4 0 0 0 0 0
0 0 0 0 2 0 1 3 4 0 1 3 3 5 3
4 0 1 4 3 3 3 3 4 4 4 4 3 0 1
1 0 0 0 0 0 4 1 1 1 0 1 0 2 2
2 1 2 0 3 1 0 0 0 3 1 0 1 1 0
0 0 0 1 0 0 1 0 2 2 0
