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A New Species of Teleoceras (Mammalia, Rhinocerotidae) from the Late Hemphillian of Tennessee

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A new species of rhinoceros, Teleoceras aepysoma n. sp., is described from the late Hemphillian-aged Gray Fossil Site of eastern Tennessee. Fossils from a minimum of six individuals, including two nearly complete, articulated skeletons, have been found at the Gray Fossil Site. Availability of such complete specimens enables a thorough morphological description of the new species. Furthermore, the diagnostic characters of T. aepysoma necessitate an emended diagnosis for the tribe Teleoceratini and genus Teleoceras. Cranial features, such as lack of rugose bone for a horn on the dorsal surface of the unfused nasals and pronounced supraorbital tubercles positioned on the frontals dorsal to the orbits, support the establishment of a new species. Additionally, linear measurements and proportions show that T. aepysoma has relatively longer forelimb elements and, thus, a more elevated body than previously described species of Teleoceras.
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BULLETIN
A NEW SPECIES OF TELEOCERAS (MAMMALIA,
RHINOCEROTIDAE) FROM THE LATE HEMPHILLIAN
OF TENNESSEE
Rachel A. Short, Steven C. Wallace, and Laura G. Emmert
Vol. 56, No. 5, pp. 183–260 April 27, 2019
ISSN 2373-9991
UNIVERSITY OF FLORIDA GAINESVILLE
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A NEW SPECIES OF TELEOCERAS (MAMMALIA, RHINOCEROTIDAE)
FROM THE LATE HEMPHILLIAN OF TENNESSEE
Rachel A. Short1,2, Steven C. Wallace2,3, and Laura G. Emmert2
1Department of Ecosystem Science and Management, Texas A&M University, College Station, Texas 77843, USA <rachel.a.short@tamu.edu>
2Don Sundquist Center of Excellence in Paleontology, East Tennessee State University Museum of Natural History, Gray, Tennessee 37615, USA <wallaces@
mail.etsu.edu>, <zlsg5@goldmail.etsu.edu>
3Department of Geosciences, East Tennessee State University, Johnson City, Tennessee 37614, USA
Short, R. A., S. C. Wallace, and L. G. Emmert. 2019. A new species of Teleoceras (Mammalia, Rhinocerotidae) from the late Hemphillian of Tennessee.
Bulletin of the Florida Museum of Natural History 56(5):183–260.
ABSTRACT
A new species of rhinoceros, Teleoceras aepysoma n. sp., is described from the late Hemphillian-aged Gray
Fossil Site of eastern Tennessee. Fossils from a minimum of six individuals, including two nearly complete,
articulated skeletons, have been found at the Gray Fossil Site. Availability of such complete specimens
enables a thorough morphological description of the new species. Furthermore, the diagnostic characters
of T. aepysoma necessitate an emended diagnosis for the tribe Teleoceratini and genus Teleoceras. Cranial
features, such as lack of rugose bone for a horn on the dorsal surface of the unfused nasals and pronounced
supraorbital tubercles positioned on the frontals dorsal to the orbits, support the establishment of a new
species. Additionally, linear measurements and proportions show that T. aepysoma has relatively longer
forelimb elements and, thus, a more elevated body than previously described species of Teleoceras.
Key words: Teleoceras, new species, Hemphillian, morphology, Gray Fossil Site, Tennessee.
TABLE OF CONTENTS
Introduction ........................................................................................................... 184
Materials and Methods ..........................................................................................186
Results ................................................................................................................... 186
Systematic Paleontology ....................................................................................... 188
Morphological Description ................................................................................... 198
Cranium ...........................................................................................................198
Dentition ..........................................................................................................202
Vertebrae and Other Axial Elements ................................................................209
Forelimb ........................................................................................................... 215
Hind Limb ........................................................................................................ 236
Phalanges and Sesamoids ................................................................................249
Discussion ............................................................................................................. 252
Acknowledgements ............................................................................................... 255
Literature Cited ..................................................................................................... 255
Appendix 1. Measurements Used for Scatterplots ................................................259
184 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
INTRODUCTION
Teleoceras is a wide-spread Miocene rhinoceros that
has been reported in North American faunas from
the late Hemingfordian to the latest Hemphillian
North American Land Mammal Ages (NALMA)
(Prothero, 1998, 2005; Tedford et al., 2004). In
2000, late Miocene fossils were found during road
construction near Gray, Tennessee (Fig. 1A–B;
Wallace and Wang, 2004), and the Gray Fossil Site
(GFS) was established at the location. In 2004,
two nearly complete, articulated rhinoceros skel-
etons (Figs. 1C, 2) were discovered and provision-
ally referred to Teleoceras cf. T. hicksi (Wallace,
2006). To date, the GFS has produced a minimum
of six individuals of Teleoceras based on the pres-
ence of four adult left astragali, a subadult femur,
and a juvenile, possibly fetal, tibia and bula pair
(Wallace, 2006); however, this number is likely to
increase as excavations continue.
At the GFS, fossil material is found primar-
ily in an organic-rich clay deposit that lled a large
sinkhole system in the Knox Group Limestone
(Wallace and Wang, 2004). The locality was not
a single sinkhole but instead a series of collapsed
sinkholes that formed a large basin and, subse-
quently, a pond, which likely served as a watering
hole for local fauna (Whitelaw et al., 2008; Zobaa
et al., 2011). The pond lled with nely laminated
lacustrine sediments and isolated gravel lenses over
4,500–11,000 years to an estimated depth of 30–40
m (Shunk et al., 2006, 2009). These ne lamina-
tions have contributed to the preservation of many
completely or partially articulated fossils.
To date, the GFS is one of three Hemphillian
fossil localities east of the Mississippi River and
outside of Florida along with the Pipe Creek Sink-
hole of Indiana and the Mauvilla local fauna of
Alabama (Farlow et al., 2001; Prothero, 2005; Hul-
bert and Whitmore, 2006). Taxa from the GFS are
a mix of North American and Eurasian lineages,
and there are genera from warm habitats, includ-
ing Alligator, Tapirus, and Heloderma, as well as
Figure 1. Geography of the Gray Fossil Site. A, Tennessee; B, Gray, Tennessee indicated with the white
star; C, positions of ETMNH 601 and ETMNH 609 at time of excavation with 1 m2 grid.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 185
genera related to modern taxa from cool habitats,
such as Arctomeles, Pristinailurus, and Gulo (Wal-
lace and Wang, 2004; Mead et al., 2012; Samuels
et al., 2018). The GFS has been biochronologically
constrained to 4.5–4.9 Ma based on fauna includ-
ing Teleoceras, Plionarctos, Gulo sudorus, Tapirus
polkensis, and three species of tayassuids (Wallace
and Wang, 2004; Hulbert et al., 2009; Doughty et
al., 2018; Samuels et al., 2018).
During the late Miocene, the North American
climate was warmer and drier than today. Expan-
sion of grasslands was producing more open habi-
tats across much of the continent’s center (Ström-
berg and McInerney, 2011). Yet, in a palynological
assessment, Ochoa et al. (2012, 2016) found that
90% of the ora at the GFS was Quercus, Carya,
and Pinus. Despite being deposited during a time of
climatic and environmental change, it is believed
that the landscape surrounding the GFS remained
a forest, possibly as a refugium, throughout its
depositional history, and that resident Teleoceras
adopted a browsing ecology (Wallace and Wang,
2004; DeSantis and Wallace, 2008).
Appearance of Teleoceras in the North Amer-
ican fossil record has been used, along with other
taxa, to indicate the beginning of the late Heming-
fordian NALMA (He2, ~17.5 Ma), and its disap-
pearance, with other taxa, indicates the termination
of the Hemphillian NALMA (Hh4, ~4.8 Ma; Ted-
ford et al., 2004). Most recently, Prothero (2005)
recognized nine species of Teleoceras: T. ameri-
canum (Yatkola and Tanner, 1979), T. medicornu-
tum Osborn, 1904, T. meridianum (Leidy, 1865),
T. brachyrhinum Prothero, 2005, T. major Hatcher,
Figure 2. Mounted cast of ETMNH 609 on public display at the East Tennessee State University Museum
of Natural History, Gray, Tennessee.
186 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
1894, T. proterum (Leidy, 1885), T. fossiger (Cope,
1878), T. hicksi Cook, 1927, and T. guymonense
Prothero, 2005.
Previous work on Teleoceras has focused on
skulls and dentition, which has caused much con-
fusion and uncertainty (Prothero, 2005); relatively
little work has been done on postcranial elements
(Mead, 2000; Prothero, 2005). With two nearly
complete skeletons available, we present the results
of a morphometric comparison of Teleoceras from
the GFS and the other nine species, recognize
the GFS specimens as a new species, and offer a
detailed, thorough bone-by-bone description of the
Teleoceras from the GFS.
MATERIALS AND METHODS
Morphological descriptions of the GFS population
were written with the aid of Barone (1999), Flower
(1876), McFadyean (1908), Osborn (1898a), and
Prothero (2005). Dental morphology is modied
from Garutt (1994) and Prothero (2005), and lin-
ear measurements come from Prothero (2005).
Five cranial measurements (i.e., distance from P2
to occiput, distance from lambdoid crest to nasals,
width at zygoma, width of occiput, and height of
occiput) and six dental measurements (i.e., lengths
of P2–M3, P2–4, M1–3, p3–m3, p3–4, and m1–3)
captured skull morphology (Fig. 3). Four postcra-
nial linear measurements (i.e., length, proximal
width, distal width, and midshaft width) were taken
on humeri, radii, ulnae, femora, tibiae, third meta-
carpals, and third metatarsals (Fig. 4). Three linear
measurements (i.e., length, midshaft width, and
width of the sustentaculum) were taken on calca-
nea (Fig. 4). Measurements were obtained with an
osteometric board and recorded to the nearest 0.1
of a millimeter or calipers and recorded to the near-
est 0.01 of a millimeter. Mean values from the GFS
were plotted with existing data (Prothero, 2005;
Appendix 1) in scatter plot matrices using R Soft-
ware (R Core Team, 2016).
AbbreviAtions
ETMNH, East Tennessee State University
Museum of Natural History; GFS, Gray Fossil
Site, Gray, Tennessee; NALMA, North American
Land Mammal Age.
RESULTS
Skulls from the GFS are larger than those of other
species of Teleoceras with a greater length from P2
to the occiput and greater widths across the zygoma
and occiput (Fig. 5; Table 1). Yet, the GFS skulls
maintain the characteristically brachycephalic
skull of the genus relative to Aphelops and Perac-
eras. Dental measurements are consistent across
the genus except for upper tooth row lengths of T.
fossiger and T. proterum, which are considerably
longer than those of other species (Fig. 5).
Postcranial measurements of the GFS speci-
mens are provided in Table 2. Humeri from the
GFS have a greater length, midshaft width, and
distal width than other species (Fig. 6). The GFS
humeri consistently plot outside of the cluster cre-
ated by other species of Teleoceras. Radii from the
GFS have a greater length than other species (Fig.
6). However, radial distal and midshaft widths from
the GFS plot within the cluster of the other Teleo-
ceras species. Ulnae from the GFS have a greater
length and midshaft width than other species and
plot considerably beyond the cluster of Teleoceras
species (Fig. 7).
Interestingly, the proportional differences
observed in the forelimb elements are not evident
in the hind limb or podial elements. Femora from
the GFS have a slightly greater length than femora
of other species (Fig. 8), but the midshaft width
and distal width plot within the cluster of Teleoc-
eras species. Tibiae from the GFS are within the
cluster of Teleoceras species for length, midshaft
width, and distal width (Fig. 8). Podial elements
are also within the cluster of Teleoceras species,
which is to be expected from a genus characterized
by derived, yet conservative, podial morphology
(Prothero, 2005; Fig. 9). Third metapodials from
the GFS have a slightly greater proximal width,
and calcanea from the GFS have a slightly greater
length and are one of the widest at the sustentacu-
lum. Teleoceras calcanea form a nearly linear trend
with the GFS at the largest end and, interestingly,
this corresponds closely to taxonomy through time.
Skulls and limb elements of the GFS Teleoc-
eras are proportionally different from the currently
recognized nine species. In addition to unique
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 187
Figure 3. Skull and dental linear measurements. 1, height of occiput; 2, lambdoid crest to nasals; 3, width
at zygoma; 4, width of occiput; 5, P2 to occiput; 6, P2−M3; 7, P2−P4; 8, M1−M3. Lower dentition was
measured similarly: p2−m3, p2−p4, and m1−m3. Measurements are from Prothero (2005).
188 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
Figure 4. Postcranial linear measurements. A, humerus; B, ulna; C, femur; D, radius; E, third metacarpal;
F, tibia; G, calcaneum. For AF: 1, maximum length; 2, maximum proximal width; 3, maximum distal
width; 4, midshaft width. For G: 1, maximum length; 2, midshaft width; 3, width of the sustentaculum.
Measurements are modied from Prothero (2005).
morphological characters, these features warrant
emended diagnoses of Teleoceratini and Teleoc-
eras as well as the designation of a new species
(Table 3).
SYSTEMATIC PALEONTOLOGY
Class MAMMALIA Linnaeus, 1758
Order PERISSODACTYLA Owen, 1848
Family RHINOCEROTIDAE Owen, 1845
Tribe TELEOCERATINI Hay, 1902
Emended diagnosis.—Retained characters
from Prothero (2005:94): “robust, attened carpals,
tarsals, and metapodials…a very brachycephalic
skull with a aring lambdoid crest and broad zygo-
matic arches…nasals that are U-shaped in cross-
section, with or without a small terminal horn… a
strong, lobal antecrochet on the upper molars, and
an elongate calcaneal tuber.” Rejected characters
from Prothero (2005) are provided in the remarks
below.
Remarks.—Presence of most characters of
Teleoceratini supports placing the GFS specimens
in this tribe rather than the subfamily Aceratheriinae
(Table 3). Aceratherines, including Peraceras and
Aphelops, were the only other North American rhi-
noceroses during the late Neogene. Aceratherines
are characterized by reduced premaxillae, reduced
medial anges of lower tusks, narrow skulls, and
long legs. The GFS fossils exhibit several distinct
features (see diagnosis below) that not only warrant
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 189
Table 1. Teleoceras aepysoma cranial measurements (mm). See Figure 3 for measurement schematic.
Mean ETMNH 601 ETMNH 609
Skull
height of occiput 196.54 201.63 191.45
lambdoid crest to nasals 455.49 493.39 417.59
width at zygoma 357.18 377.15 337.21
width of occiput 235.61 246.29 224.94
P2 to occiput 519.76 530.74 508.78
Dentition
P2–M3 265.99 264.45 267.54
P2–P4 116.29 114.06 118.53
M1–M3 158.85 162.42 155.29
p3–m3 246.84 249.44 244.24
p3–p4 82.33 82.21 82.46
m1–m3 165.74 167.60 163.89
erection of the new species, but also call in to ques-
tion some of the characters used to dene the tribe.
The new species described below justies remov-
ing the following characters from the tribe diagno-
sis of Prothero (2005:94): “short, stumpy limbs…
[and] a nasal incision retracted to anterior P3 (not
as far as in aceratheriines).” The latter character is
not evident on examined skulls of Teleoceras and
is believed to be poorly dened.
Genus TELEOCERAS Hatcher, 1894
Emended diagnosis.—Retained characters
from Prothero (2005:94): “medium- to large-sized
teleoceratin rhinos with hypsodont teeth, strong
antecrochets, greatly reduced premolars with dP1/
p1 lost and occasional loss of P2/p2, thick cement
on teeth, narrow nasals with strongly downturned
lateral edges, enlarged premaxilla and I1, broad
zygomatic arches, aring lambdoid crests (skull
semicircular in posterior view)…lower tusk (i2)
shaped like a teardrop in cross-section, and…bar-
rel-shaped trunk.” Rejected characters from Pro-
thero (2005) are provided in the remarks below.
Included species.—T. americanum (Yatkola
and Tanner, 1979); T. medicornutum Osborn, 1904;
T. brachyrhinum Prothero, 2005; T. meridianum
(Leidy, 1865); T. fossiger (Cope, 1878); T. proterum
(Leidy, 1885); T. hicksi Cook, 1927; T. guymonense
Prothero, 2005; T. aepysoma n. sp.
Remarks.—Teleoceras is the only North
American genus of Teleoceratini, and presence
of most characters supports referring the GFS
specimens to this genus (Table 3). The GFS fos-
sils exhibit several distinct features (see diagnosis
below) that not only warrant erection of the new
species, but also call in to question some of the
characters used to dene the genus. Specically,
the new species justies removing the following
characters from the generic diagnosis of Prothero
(2005:94): “a small terminal nasal horn and fused
nasals…teleoceratin body proportions…and short,
robust limbs.”
TELEOCERAS AEPYSOMA n. sp.
Teleoceras sp. Parmalee et al. (2002); Wallace and Wang
(2004); Shunk (2006)
Teleoceras cf. T. hicksi Shunk et al. (2006); DeSantis and
Wallace (2008); Hulbert et al. (2009)
Teleoceras sp. nov Wallace et al. (2014)
Diagnosis.—Teleoceras aepysoma has
190 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
Table 2. Teleoceras aepysoma postcranial measurements (mm). See Figure 4 for measurement schematic.
For the metacarpal, the mean is calculated from the means of individuals to prevent duplicating values for
ETMNH 601 and ETMNH 609. Unavailable measurements are indicated with dashes, and unavailable
elements are indicated with a gray background.
Mean
ETMNH 601
Right
ETMNH 601
Left
ETMNH 609
Right
ETMNH 609
Left
ETMNH 8271
Right
Humerus
Length 392.5 -- -- 392.0 393.0
Proximal Width 157.6 161.0 -- 150.0 158.5
Distal Width 154.1 161.5 161.5 146.8 146.8
Midshaft Width 76.08 77.27 75.58 74.02 77.44
Ulna
Length 388.8 403.5 401.0 372.0 378.5
Proximal Width 53.21 57.78 58.45 45.88 50.74
Distal Width 66.72 68.59 67.54 66.97 63.78
Midshaft Width 59.20 60.50 59.80 58.57 57.91
Radius
Length 310.6 328.3 321.8 296.5 295.8
Proximal Width 100.4 101.8 103.0 99.0 98.0
Distal Width 97.9 103.0 103.5 93.3 91.8
Midshaft Width 48.84 51.89 52.22 45.36 45.89
MC3
Length 125.6 140.3 139.0 118.0 118.5 119.0
Proximal Width 69.8 77.0 75.0 67.0 66.0 67.0
Distal Width 64.8 73.5 73.0 60.3 59.5 61.3
Midshaft Width 52.11 58.03 58.55 48.65 48.79 49.32
Femur
Length 491.6 505.8 513.3 472.3 475.0
Proximal Width 190.4 200.0 196.8 183.3 181.5
Distal Width 134.4 140.5 139.8 129.0 128.5
Midshaft Width 69.99 75.21 73.13 66.15 65.50
Tibia
Length 271.5 -- 290.8 253.0 251.5
Proximal Width 112.2 122.0 117.5 103.3 105.8
Distal Width 90.1 94.3 94.8 87.0 84.3
Midshaft Width 51.44 -- 53.35 51.41 47.67
Calcaneum
Length 140.2 149.5 151.0 130.0 130.3
Midshaft Width 44.30 48.20 44.56 41.54 42.91
Width at Sustentaculum 77.06 81.67 79.56 75.52 71.50
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 191
Figure 5. Measurements of Teleoceras skulls and dentition. See Figure 3 for measurement schematic.
Teleoceras aepysoma data are compared to data from Prothero (2005; see Appendix 1).
Table 2. Continued.
MT3
Length 105.2 114.5 113.0 96.3 97.0
Proximal Width 54.3 56.0 57.5 52.0 51.5
Distal Width 59.8 64.3 66.5 53.8 54.5
Midshaft Width 45.53 49.73 50.11 40.89 41.41
192 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
Figure 6. Measurements of Teleoceras humeri and radii. See Figure 4 for measurement schematic.
Teleoceras aepysoma data are compared to data from Prothero (2005; see Appendix 1).
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 193
large skulls with a greater length from P2 to the
occiput and greater widths across the zygoma
and the occiput than other species of Teleoceras.
As adults, male T. aepysoma have unfused nasals,
lack evidence of a nasal horn, and have extensive
dorsal tubercles superior to the orbits (supraorbital
tubercles). Forelimb bones (i.e., humerus, radius,
and ulna) of T. aepysoma are longer than in other
species of Teleoceras. Humeri and ulnae also have
greater midshaft widths and distal widths. In the
hind limbs, femora are slightly longer than other
species of Teleoceras. As a result of the longer limb
bones, the body of T. aepysoma is more elevated,
especially at the front end, than is typical of the
genus. Characters are provided in Table 3.
Etymology.—“Aepy,” Greek for high or
tall, and “soma,” Greek for body; referring to
the elevated stance of this species relative to
congenerics.
Types.—Holotype, ETMNH 609, complete
Figure 7. Measurements of Teleoceras ulnae. See
Figure 4 for measurement schematic. Teleoceras
aepysoma data are compared to data from Prothero
(2005; see Appendix 1).
skeleton, missing only one distal phalanx. Paratype,
ETMNH 601, nearly complete skeleton. Type
locality is the Gray Fossil Site, Gray, Washington
County, Tennessee, USA (Fig. 1). A cast of the
holotype is on public display at the ETMNH (Fig.
2). A paratype is assigned because of its better-
preserved skull (Fig. 10).
Zoobank Nomenclatural Act.—D3CCE3BC-
98AA-4D98-8727-86999FC6D248.
Occurrence.—Latest Hemphillian, late Mio-
cene to early Pliocene. Teleoceras aepysoma is cur-
rently only known from the Gray Fossil Site, Gray,
Washington County, Tennessee.
Referred specimens.—Partial skeleton:
ETMNH 19280; Cranial: ETMNH 12175, 17351,
17352, 17353, 21659; Dentition: ETMNH 566,
780, 781, 3763, 5235, 7894, 12487, 13914; Ver-
tebra: ETMNH 559, 573, 3751, 12175, 13510,
17354; Rib: ETMNH 3747, 3752, 3754, 4286,
6037, 6649, 6749, 7291, 7294, 8173, 8182, 8636,
10959, 12242, 14174, 14710, 14894, 17355,
17356; Humerus: ETMNH 5057, 6648; Ulna:
ETMNH 502, 8762; Partial manus: ETMNH 8271;
Trapezium: ETMNH 13236; Magnum: ETMNH
8516; Femur: ETMNH 3721; Tibia with bula:
ETMNH 19025; Astragalus: ETMNH 1901, 6647,
14175; Mesocuneiform: ETMNH 3749; Metapo-
dial: ETMNH 565; Podial: ETMNH 62; Phalanx:
ETMNH 80, 107, 564, 712, 713, 743, 769, 3755,
4381, 5233, 11651, 12175, 12450, 12776, 12777,
13031, 13968, 17357.
Remarks.—All specimens from the GFS are
well-preserved with minimal breakage or other dis-
tortion. Two nearly complete skeletons have been
recovered along with isolated elements from other
individuals. ETMNH 609 is smaller and is only
missing the distal phalanx of the left hind fourth
digit. ETMNH 601 is a larger individual, but is
less complete than ETMNH 609. ETMNH 601 has
the skull, dentition, and most of the appendicular
skeleton, though it is more damaged than that of
ETMNH 609; however, ETMNH 601 is missing
most of the axial skeleton. ETMNH 19280 is a
partial skeleton that includes a fragmented dentary
with fragmented teeth, partial vertebrae and ribs,
right distal tibia and bula, left third metatarsal,
194 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
Figure 8. Measurements of Teleoceras femora and tibiae. See Figure 4 for measurement schematic.
Teleoceras aepysoma data are compared to data from Prothero (2005; see Appendix 1).
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 195
and associated unidentied fragments.
Both ETMNH 609 and ETMNH 601 are con-
sidered males because of their large, tusk-like i2s.
This is in contrast to the smaller i2s found in female
rhinoceroses (Osborn, 1898a, 1898b; Voorhies and
Stover, 1978; Dinerstein, 1991). Both skeletons are
also adults based on the degree of epiphyseal fusion
and tooth wear. The upper tooth row of ETMNH
609 matches age class XI of Hitchins (1978) and
the lower tooth row matches age class X. The larger
ETMNH 601 matches age class XIII of Hitchins
(1978) on the upper teeth and age class XII on the
lower teeth. Using Mihlbachler’s (2003) life span
percentages, ETMNH 609 was at the beginning of
an age class marking 25–35% of its potential life
span and ETMNH 601 was at the beginning of an
age class marking 35–52% of its potential life span.
In extant Diceros, these life span percentages refer
to 8–12 years old and 11–18 years old, respectively
(Hitchins, 1978).
Mass estimates suggest Teleoceras aepy-
soma is quite large. Using equations based on the
circumferences of the humerus and femur (Ander-
son et al., 1985), the mass of ETMNH 609 is esti-
mated to be 1488 kg and 1335 kg, respectively,
and that of ETMNH 601 is estimated to be 2330
kg and 2147 kg. These same equations produced
mass estimates of 702 kg and 568 kg for T. pro-
terum from the Love Bone Bed (MacFadden and
Hulbert, 1990). The substantially greater mass
estimates for T. aepysoma are corroborated by cal-
culations using the calcaneum and constants from
two modern rhino taxa (Ceratotherium simum and
Diceros bicornis) (Christiansen, 2002). Mass was
estimated separately for each constant and then
averaged. Using this method, the estimated masses
of ETMNH 609 and ETMNH 601 are 1544 kg and
2268 kg, respectively.
Figure 9. Measurements of Teleoceras podial
elements. See Figure 4 for measurement schematic.
Teleoceras aepysoma data are compared to data
from Prothero (2005; see Appendix 1).
196 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
Table 3. Morphological characters of Teleoceratini, Teleoceras, and T. aepysoma n. sp. Teleoceratini
synapomorphies and Teleoceras characters are quoted from Prothero (2005:94). Those that are present in
Teleoceras aepysoma are indicated with ‘*,’ those absent are indicated with ‘X,’ and one that is questionably
dened is indicated by ‘?.’
Synapomorphies of Teleoceratini T. aepysoma
1. short, stumpy limbs X
2. robust, attened carpals, tarsals, and metapodials *
3. very brachycephalic skull *
4. aring lambdoid crest *
5. broad zygomatic arches *
6. nasals that are U-shaped in cross-section *
7. nasals with or without a small terminal horn *
8. nasal incision retracted to anterior P3 (not as far as in aceratheriines) ?
9. strong, lobal antecrochet on the upper molars *
10. elongate calcaneal tuber *
Characters of Teleoceras T. aepysoma
1. hypsodont teeth *
2. strong antecrochets *
3. greatly reduced upper and lower premolars *
4. deciduous p1s lost and occasional loss of p2s *
5. thick cement on teeth *
6. narrow nasals with strongly downturned lateral edges *
7. enlarged premaxilla and I1 *
8. broad zygomatic arches *
9. aring lambdoid crests (skull semicircular in posterior view) *
10. small terminal nasal horn X
11. fused nasals X
12. i2 (tusk) shaped like a teardrop in cross-section *
13. teleoceratine body proportions of a barrel-shaped trunk and short,
robust limbs X
New Characters of Teleoceras aepysoma
1. greater length from P2 to the occiput than other species
2. greater widths across the zygoma and the occiput than other species
3. unfused nasals
4. no evidence of a nasal horn
5. extensive dorsal tubercles superior to the orbits
6. humerus, radius, ulna, and femur with greater lengths than other species
7. humerus and ulna with greater midshaft and distal widths than other species
8. more elevated body than considered typical of the genus
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 197
Figure 10. Cranium of ETMNH 601 in three views. The upper tusks are removed in this image. A, right
lateral view; B, dorsal view; C, ventral view. Anterior is to the right in all three. Scale bar = 10 cm.
198 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
MORPHOLOGICAL DESCRIPTION
CrAnium
Nasal.—Anteriorly, the nasals are round in
cross-section and, when visible, articulate along a
coarsely serrated suture (Fig. 11). No evidence of
a horn attachment is present on the smooth dorsal
surface. Ventrally, the surface is concave and has
an anteroposterior ethmoid crest. Nasals become
progressively thicker in cross-section toward the
anterior suture. ETMNH 609 has only slightly
more anteriorly upturned nasals than the straight
nasals of ETMNH 601.
Frontal.—Dorsally, the frontals are at
except for laterally extending supraorbital tubercles
positioned dorsal to the orbits that are unique to
this taxon (Fig. 12).
Parietal.—Laterally, the parietals are
inated around the braincase (Fig. 13). A broad
concavity is present at the articulation between
the squamosal and the parietal and dorsal to the
external auditory meatus. Paired temporal crests
extend posteromedially from the supraorbital
tuberosities of the frontals until they nearly merge
dorsally, before separating at the lambdoid crest;
the temporal crests of ETMNH 601 merge to form
a sagittal table.
Premaxilla.—Premaxillae of ETMNH 601
are complete and are nearly articulated at their
anterior-most point (Fig. 14). Anteroventrally-
oriented tusk alveoli are present and support the
I1s. Premaxillae of ETMNH 601 are medially
attened, laterally ared, dorsally rounded, and
posteroventrally pinched. No nasal or palatine
processes are present and there is no evidence of
an incisive foramen. Both premaxillae of ETMNH
609 have been entirely reconstructed so that the
upper tusks occlude with the lower tusks.
Maxilla.—Except for the incisors, the
maxilla supports the entirety of the upper tooth row
(Fig. 15). Though the facial surfaces are present,
most of the internal maxilla of ETMNH 601 is
missing. Between the premaxillae articulations, the
maxillae are concave to form a rounded incisive
cleft at the anterior end of the palate. On the lateral
surface, there is a concavity anterior to the lacrimal
and ventral to the nasal.
Posterolaterally, the maxilla expands
laterally to articulate with the jugal and form the
anterior zygomatic arch. The maxillary tuberosity
continues posteromedially to the jugal articulation
at the end of the tooth row. A superior maxillary
sinus is within the maxillary tuberosity. A facial
crest is bordered by a groove between the maxillary
tuberosity and the jugal articulation. Both ETMNH
601 and ETMNH 609 have anteriorly deep
maxillary palates that rise to the level of the tooth
alveoli at the posterior end.
Lacrimal.—This small bone forms the
anterior edge of the orbit (Fig. 16). Though the facial
surface is rugose, the orbital surface is smooth.
There is a laterally-directed lacrimal foramen just
beneath a laterally-protruding lacrimal tubercle.
Jugal.—The jugal articulates with the maxilla
superior to the M1 and M2 (Fig. 17). With the
squamosal, the jugal forms the broad and rugose
zygomatic arch. Minimal roughness is present
on the facial surface, but along the ventral edge
of the orbit, the jugal is smooth. There are heavy
rugosities on the medial side of the zygomatic arch.
Squamosal.—Like the jugal, the medial
surface of the squamosal has prominent muscle
scarring (Fig. 18). The posterolateral squamosal
is more rugose along the medial curve from the
zygomatic arch to the parietal articulation and, in
doing so, forms the lateral boundary of the temporal
fossa. A transversely elongate glenoid fossa has an
open angle and is only slightly concave. Anterior
to the glenoid fossa, the articular tubercle is round,
but it appears pinched anteriorly. Post-glenoid
processes are nearly straight and elongate but
are shorter than the paroccipital processes of the
occipital. These two processes fuse ventral to the
external auditory meatus to form the mastoid crest
but are then separated by a ‘V’-shaped notch. Dorsal
to the external auditory meatus, the squamosal and
occipital bones fuse to form the lambdoid crest.
There is no evidence of external auditory bullae.
Occipital.—On the posteroventral surface,
the triangular (in posterior view), convex occipital
condyles are lateral to the foramen magnum (Fig.
19). On the ventral surface, the paired hypoglossal
foramina are anterior to each of the occipital
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 199
condyles and medial to each paroccipital process.
Most of the occipital extends in the same plane as
the occipital condyles and only the dorsal-most
lambdoid crest extends more posteriorly. Edges
of the occipital form the lambdoid crest with the
squamosal and parietals. At the ventral point of
the external auditory meatus, the lambdoid crest
meets the crest of the post-glenoid process and then
continues as the paroccipital process. ETMNH 609
has an asymmetrical lambdoid crest that may be
due to pathology but further examination is needed.
Basicranium.—Because of the large amount
of fusion, it is difcult to discern the individual
bones of the basicranium, so it will be described
Figure 11. Nasals of ETMNH 601. A, dorsal view; B, anterior view; C, right lateral view. In A and B, the
scale bar = 5 cm. In C, the scale bar = 10 cm.
200 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
Figure 12. Frontals of ETMNH 601. A, right lateral view; B, dorsal view. Abbreviations: DOK, dorsal
orbit knobs; OR, orbit; TF, temporal fossa. Scale bar = 10 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 201
Figure 13. Parietals of ETMNH 601. A, right lateral view; B, dorsal view. Abbreviations: CV, concavity;
EAM, external auditory meatus; LCT, lambdoid crest; TCT, temporal crest. Scale bar = 10 cm.
202 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
Figure 14. Premaxillae of ETMNH 601. Views: A,
right lateral; B, anterior. Abbreviations: TAL, tusk
alveolus. Scale bar = 10 cm.
here as a region (Fig. 20). Ventrally, the basicranium
is in poor condition on both crania. There is a
ventral muscle tubercle anterior to what is most
likely the articulation between the occipital and the
basisphenoid. Each lateral side of this region has
an alisphenoid canal that is bridged by bone, likely
the alisphenoid, with prominent surcial ridges.
A dorsal opening to this canal is anterior and the
canal gently curves posteroventrally.
Pterygoid.—Pterygoid processes are directed
posteroventrally and almost to the height of the M3
(Fig. 21).
Palatine.—Almost all of the palatine of
ETMNH 601 has been repaired with mesh making
it nearly impossible to describe any morphology
(Fig. 22).
Vomer.—The unpaired vomer is missing
from both skulls.
Hyoid Apparatus.—The basihyoid is round
but is dorsoventrally compressed and lacks a lingual
process (Fig. 23). The left thyrohyoid of ETMNH
601 is present and it extends posterolaterally from
the basihyoid. A rugose knob forms the articulation
and the thyrohyoid tapers so that it is mediolaterally
compressed. The ceratohyoid is short with rounded
sides, and it would articulate between the basihyoid
and the epihyoid; though, no epihyoids are present.
Finally, the stylohyoid articulates with the epihyoid
and the tympanohyoid cartilage. The stylohyoid is
the largest of the hyoid bones and is mediolaterally
compressed with a medial fossa at the proximal
end. There are no tympanohyoids present. North
American rhinoceros hyoids were previously only
known from Teleoceras major at Ashfall Fossil
Beds State Historical Park (Prothero, 2005).
Mandible.—Overall, the mandible is much
longer than it is tall and the intermaxillary space is
‘V’-shaped (Fig. 24). A shallow, sloping symphysis
with a broad lingual surface is present between the
dentaries and extends posteriorly to the middle of
the p4. Angles of the dentaries are ared laterally
and are rugose, especially on ETMNH 601, which
is likely due to increased muscle attachment
associated with a more advanced age. Each lateral
surface has a broad and shallow masseteric fossa
that is dorsal to the angular rugosities, which are
present on both the medial and lateral side of the
dentary. Though there are no angular processes,
shallow mandibular incisures separate thin,
rounded coronoid processes from transversely long
and convex articular condyles. Posterior to each
articular condyle, there is a second convex surface
that merges with the lateral articular condyle and
slopes medioventrally.
Below the medial edge of the tusks, there are
variable foramina. A short diastema is transversely
pinched behind the tusks and separates the tusks
from the p2, if present, or the p3. A mental foramen
is found inferior to the anterior root of the p4. An
inferior mandibular foramen is on the internal
pterygoid fossa of the ramus at the same level as
the tooth row.
Dentition
Along each upper tooth row, there is a
modied incisor and six lophodont cheek teeth.
Along each lower tooth row, there is a modied
incisor and ve functional, lophodont cheek teeth.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 203
Figure 15. Maxillae of ETMNH 601. Views: A, right lateral; B, ventral. Abbreviations: CV, concavity;
FCT, facial crest; IOF, infraorbital foramen; MPL, maxillary palate; MTB, maxillary tuberosity; NI, nasal
incision; TR, tooth row. Scale bar = 10 cm.
Some lower dentitions include vestigial p2s that are
not functional. Dental nomenclature is provided in
Figure 25.
Upper Incisors.—Upper tusks are modied
I1s that are smaller than the lower tusks (Fig. 26).
These upper tusks are ovate, elongate mediodorsally
to lateroventrally, and function to hone the lower
tusks during occlusion. Similar upper tusks are
present in other species of Teleoceras, while these
are lacking in Aphelops and Peraceras, the other
common late Neogene rhinoceroses of North
America (Prothero, 2005).
204 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
Figure 16. Right lacrimal of ETMNH 601 in lateral view. Abbreviations: FS, facial surface; LF, lacrimal
foramen; LTB, lacrimal tuberosity; OS, orbital surface. Scale bar = 10 cm.
Upper Cheek Teeth.—Occlusal surfaces of
the upper cheek teeth make the ‘π’ shape that is
characteristic of rhinoceroses (Fig. 27). Upper
premolars are rectangular with the longest axis
oriented labiolingually, and, though the M1 is nearly
square, the M2 is longer anteroposteriorly. M3s are
smaller and form a triangular shape because the
crochet is folded within the antecrochet. The P2s
have very small crochets, and P3–M3 have large
crochets and antecrochets. In all of the premolars,
the ectoloph is either shorter than or equal in length
to the protoloph and metaloph. Three lophs of the
M1s are subequal in length whereas the ectolophs
of the M2s are longer than both the protolophs
and the metalophs of the same tooth. On the
M3s, there are no metalophs, and the ectolophs
are approximately the same length or longer than
the protolophs. On P3–M3, the anterior parastyle
overlays the posterior metastyle of the previous
tooth. All upper cheek teeth have slight depressions
lined by cingula on the anterior and lingual sides of
the protocone, and all molars have a slight paracone
fold on their labial surfaces. On some teeth, small
folds of enamel protrude into the fossettes (e.g., P4
of ETMNH 609, Fig. 27B).
Lower Incisors.—Lower tusks are i2s that
have a tear-drop shaped cross-section with the
point directed medially (Fig. 28). Complete tusks
of ETMNH 609 and ETMNH 601 have concave
wear surfaces caused by occlusion with the upper
tusks resulting in a sharp edge and apex.
Lower Cheek Teeth.—Most often, p1 and p2
are absent from Teleoceras dentition. There are no
p1s present in T. aepysoma; however, presence of
the p2 is variable. ETMNH 601 does not have p1
or p2 on either side; however, ETMNH 609 has a
small vestigial p2 (Fig. 29) that was rst noted by
Wallace (2006), and ETMNH 21659 has both the
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 205
Figure 17. Jugals of ETMNH 601. Views: A, right lateral; B, ventral. Abbreviations: OF, orbital oor; OR,
orbit; ZMA, zygomatic arch. Scale bar = 10 cm.
206 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
Figure 18. Squamosals of ETMNH 601. Views: A, right lateral; B, ventral; Abbreviations: ATB, anterior
tubercle; GF, glenoid fossa; PGP, post-glenoid process; POC, paroccipital process; TF, temporal fossa.
Scale bar = 10 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 207
Figure 19. Occipital of ETMNH 601. Views: A, ventral; B, posterior. Abbreviations: EAM, external
auditory meatus; FM, foramen magnum; HGF, hypoglossal foramen; LCT, lambdoid crest; MCT, mastoid
crest; OCD, occipital condyles; POC, paroccipital process. Scale bar = 10 cm.
208 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
Figure 20. Basicranium of ETMNH 601. Views: A, ventral; B, right ventrolateral, beneath zygomatic
arch, with arrows pointing at both ends of the alisphenoid canal. Abbreviations: ASC, alisphenoid canal;
MTB, muscle tubercle. Scale bar = 10 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 209
right and left p2s. Lower premolars have the ‘W’
shape that is characteristic of rhinoceroses and lack
signicant cingula (Fig. 30).
vertebrAe AnD other AxiAl elements
Atlas.—A round dorsal tubercle is present
along the midline of the dorsal arch, which narrows
caudally (Fig. 31). A minimal ventral tubercle mir-
rors the odontoid process of the axis. The ventral
arch is more robust than the dorsal arch. Dorsally,
the neural canal is round and, ventrally, it is ‘U’-
shaped. At the base of the dorsal arch, lateral ver-
tebral foramina are located slightly more cranially.
Transverse foramina are present on the medioven-
tral surface of the transverse processes. At the lat-
eral-most ends of the transverse processes, there is
a great amount of rugose bone present on ETMNH
601 that is not present on ETMNH 609; likely this
is because ETMNH 601 is the older and larger of
the two individuals. On the cranial surface, articular
surfaces for the occipital condyles are craniomedi-
ally depressed to form a pair of concave tear-drop
shaped facets that narrow ventromedially. Caudal
articular surfaces are ovate with the elongate axis
extended mediolaterally from the ventral neural
canal to the transverse vertebral foramina.
Axis.—Axes are taller and wider than they
are long and have large rounded odontoid pro-
cesses for articulation with the atlas (Fig. 32).
Caudally, the centrum is concave as typically seen
in the opisthocoelous vertebrae of perissodactyls.
Dorsally, the neural canal is domed, but, ventrally,
it is attened. Transverse foramina are present;
though they are completely closed on ETMNH
601 and only partially closed on ETMNH 609.
Figure 21. Pterygoids of ETMNH 601 in ventral view. Abbreviation: PGP, pterygoid process. Scale bar
= 10 cm.
210 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
Only minimal transverse processes are present.
Prezygapophyses are expanded mediolaterally
from the odontoid process. Postzygapophysis pro-
cesses extend laterally and caudally to form ovate
facets. Deep cranial notches are present dorsal to
the prezygapophyses and caudal vertebral notches
are rounded between the ventral postzygapophyses
and the dorsal centrum.
Third–Seventh Cervical Vertebrae.—Dor-
sally, the neural canal is domed and, ventrally, it is
attened along the dorsal side of the centrum (Fig.
33). On the ventral surface of the centra, there is no
evidence of any hemal structures. Round prezyg-
apophyses are present on the dorsal surface of
the anterior prominences of the vertebrae. These
articulate with the round postzygapophyses that
are present on the ventral surface of the posterior
prominences. Through the cervical series, the neu-
ral spines transition from short to pronounced, and
the transverse processes vary from a simple, later-
ally-ared extension on the third cervical vertebra
to a larger, lateral process with dorsal and ventral
Figure 22. Palatines of ETMNH 601 in ventral view. Scale bar = 10 cm.
Figure 23. Hyoid apparatus of ETMNH 601 with
ceratohyoid from ETMNH 609. Image in dorsal
view with anterior to the right. Abbreviations: BAS,
basihyoid; CER, ceratohyoid; STY, stylohyoid;
THY, thyrohyoid. Scale bar = 10 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 211
Figure 24. Mandible of ETMNH 601. Views: A, right lateral; B, dorsal. Abbreviations: ACD, articular
condyle; AD, angle of dentary; CNP, coronoid process; DIA, diastema; IMS, intermaxillary space;
MDB, mandibular body; MDI, mandibular incisure; MSF, masseteric fossa; MTF, mental foramen; PGF,
pterygoid fossa; SYM, symphysis. Scale bar = 10 cm.
212 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
Figure 25. Dental morphology and nomenclature. A, Left M2 of ETMNH 601; B, Right m2 of ETMNH
601. Abbreviations: ACT, antecrochet; ALD, anterior lophid; ALV, anterior lingual valley; CT, crochet;
ECD, entoconid; EL, ectoloph; FOS, fossette; HC, hypocone; HCD, hypoconid; ML, metaloph; MS,
metastyle; MTC, metacone; MTCD, metaconid; PCC, protocone constriction; PCF, paracone fold; PLD,
posterior lophid; PL, protoloph; PLV, posterior lingual valley; PRC, paracone; PRCD, paraconid; PS,
parastyle; PTC, protocone; PTCD, protoconid; PTF, post-fossette.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 213
extensions on the sixth cervical vertebra. Charac-
teristic transverse foramina are found just lateral to
the centra at the origin of the transverse processes.
The seventh cervical vertebrae resemble the third
through sixth except there is a longer neural spine,
a lack of transverse foramina lateral to the centrum,
and the transverse processes are missing the ventral
processes.
Thoracic Vertebrae.—ETMNH 609 has 18
thoracic vertebrae that articulate with 18 pairs
of ribs, all of which were articulated when the
specimen was found (Figs. 1C, 34). ETMNH
601 has an incomplete thoracic series with only
10 fragmented and concreted vertebrae present.
Neural spine height arcs throughout the thoracic
series with the third thoracic as the apex until
the height becomes consistent at the thirteenth
thoracic. In addition to height, the neural spines
become more caudally directed through the series.
Thoracic neural canals change from triangular at the
anterior end of the series to round at the posterior
end. Thoracic centra also change from round at
the anterior end to heart-shaped at the posterior
end. Between the neural spine and the transverse
process, the dorsal vertebral arch is more obtuse in
the anterior thoracics and becomes more acute in
the posterior thoracics.
On the rst two thoracic vertebrae, the
prezygapophyses resemble those on the cervical
vertebrae, but, beginning with the third thoracic,
the prezygapophyses are smaller in size and are
at the base of the anterior neural spine. Through
the craniocaudal progression, the dorsal notch
between the prezygapophyses becomes narrower
and extends more caudally as the prezygapophyses
shift medially. Small postzygapophyses are at the
Figure 26. Left I1 tusks with occlusal surface down. A, ETMNH 601; B, ETMNH 609. Scale bar = 5 cm.
214 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
base of the posterior neural spine for articulation
with the prezygapophyses of the subsequent verte-
bra. First and second thoracic vertebrae have prom-
inent transverse processes and articulate with small
ribs. Third through eighteenth thoracic vertebrae
have small transverse processes and articulate with
larger ribs. There are three articular surfaces for
ribs—the articular facet for the anterior rib head,
the articular facet for the posterior rib head, and
the costal fovea. Throughout the thoracic series,
the size and shape of these facets varies and, in
some cases, the anterior articular facet and the cos-
tal fovea merge. The eighteenth thoracic lacks the
posterior articular facet. On the posterior surface
of each vertebra, caudal notches separate the trans-
verse processes from the posterior articular facets.
Lumbar Vertebrae.—There are only three
lumbar vertebrae on ETMNH 609; however, none
are preserved on ETMNH 601 (Fig. 35). This is
in contrast to many North American rhinocerotids
who typically have ve lumbar vertebrae (Prothero,
2005); though, modern rhinos are known to have
variable vertebral counts both across and within
species (Heller, 1914). Lumbar neural spines are
thin, anteroposteriorly wide, and angled posteri-
orly. Lumbar neural canals are triangular, and they
widen through the series. Lumbar vertebrae have
considerably more acoelous centra than the tho-
racic vertebrae. The posterior centrum of the last
lumbar is oval for articulation with the sacrum. The
rst lumbar vertebra has tighter anterodorsal pro-
cesses for articulation with the last thoracic; these
are more wide-set on the last lumbar. Prezygapoph-
yses are small ovals on either side of the medial
notch. Oval postzygapophyses are on the ventral
side of the neural spine and on either side of the
Figure 27. Right upper cheek teeth (P2–M3) in occlusal view with anterior to the right. A, ETMNH 601;
B, ETMNH 609. Scale bar = 10 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 215
dorsal notch. Transverse processes are smallest on
the rst lumbar vertebrae and largest on the second.
On the third lumbar vertebra, the transverse pro-
cesses have at, rugose articular surfaces on their
caudal surfaces for articulation with the wings of
the sacrum.
Sacrum.—Four sacral vertebrae fused to
form the triangular sacrum that is wide cranially
and narrows caudally (Fig. 36). ETMNH 609 has
a complete sacrum but very little of the sacrum of
ETMNH 601 is preserved. Sacral foramina are pres-
ent on either side of the neural spines and between
each adjacent pair of sacral vertebrae. The neural
canal appears to be triangular, but this may be an
effect of preservation because part of the dorsal
surface has collapsed into the caudal portion of the
canal. Ovate centra are transversely elongated and
dorsoventrally shortened. The rst sacral vertebra
Figure 28. Left i2 tusks in occlusal view. A,
ETMNH 609; B, ETMNH 601. Scale bar = 10 cm.
has bulbous prezygapophyses for articulation with
the third lumbar vertebra. Rugose cranial margins
of the sacral wings are attened and turned dor-
sally so that their dorsal surfaces articulate with the
ventral ilia. Caudal notches are smaller than cranial
notches and form minimal postzygapophyses that
articulate with the rst caudal vertebra.
Caudal Vertebrae.—ETMNH 609 has 21
caudal vertebrae and ETMNH 601 has 23 (Fig.
37). Through the caudal series, the vertebrae
change from a typical vertebral morphology to a
more general, non-descript morphology. The rst
four caudals have distinct neural spines, which
become progressively minimized through the cau-
dal series. Transverse processes are present on the
cranial-most caudals and become smaller until they
are simple protuberances just over midway through
the caudal series before being lost completely. A
dorsoventrally compressed, triangular neural canal
curves laterally over the centrum on the anterior
caudals, and approximately midway through the
series, the neural canal is more round and opened
by the posterior progression of the dorsal neural
canal notch. The rst three caudal vertebrae have
small round remnants of pre- and postzygapophy-
ses; however, after the third caudal, the only articu-
lation between caudals occurs at the centra.
Sternebrae.—Sternebrae of ETMNH 609
include the long manubrium with a triangular pro-
tuberance, one short sternebra that is compressed
on the craniocaudal axis and expanded at both
ends, and one round sternebra (Fig. 38).
Ribs.—ETMNH 609 has 18 pairs of ribs
and ETMNH 601 only has incomplete fragments
that do not produce an accurate count. Overall, the
ribs are rather unremarkable in their morphology;
although, ETMNH 601 has two ribs with patholo-
gies (Fig. 39). In addition, each complete skeleton
has pieces of ossied costal cartilage that are char-
acteristically very porous.
Forelimb
Scapula.—Robust scapulae are nearly trian-
gular in shape with a slightly convex cranial bor-
der that is rugose, especially at the proximal angle
where it meets the heavily rugose vertebral bor-
der (Fig. 40). A concave vertebral border extends
216 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
Figure 29. Vestigial left p2 of ETMNH 609. Tooth of interest is indicated by the rectangle. Scale bar = 10
cm.
Figure 30. Left lower cheek teeth (p3–m3) in occlusal view with anterior to the right. A, ETMNH 601; B,
ETMNH 609. Scale bar = 10 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 217
to form a prominent, rugose angle with the rather
straight caudal border. A wide scapular neck sepa-
rates the broad scapular blade from the distal site of
articulation. An ovate and gently concave glenoid
fossa forms the distal end of the scapula and artic-
ulates with the humeral head. The glenoid fossa
has well-dened edges, except the craniolateral
edge, which is modied into a rounded surface as
if folded toward the coracoid process to create an
extra point of articulation with the proximal head
of the humerus.
The scapular spine extends nearly the length
of the element from just distal of the vertebral
point to just proximal of the glenoid fossa. The
spine is prominently elevated and curves over
the infraspinous fossa toward the caudal angle.
Distally, the scapular spine is more elevated, but
it slopes to the level of the fossae as it extends
proximally. A heavily rugose spinal tuber is
triangular but has a rounded apex directed caudally.
Medially, the underside of the spine is marked by
a depression. Laterally, the smaller supraspinous
fossa is depressed near the scapular spine and
raised at the cranial border. In the same view, the
larger infraspinous fossa is nearly at, except for a
slight raise along the caudal border.
Humerus.—The articular head extends
posterodistally, so that it curves onto the posterior
surface of the humerus (Fig. 41). On the proximal
surface, there is a depression posterior to the lesser
and intermediate tuberosities and anterior to the
humeral head for articulation with the craniolateral
portion of the scapula’s glenoid fossa. The greater
tuberosity extends proximomedially and with a
distinct curvature; the greater tuberosity is broken
off of both humeri of ETMNH 601. The convexity
of the lesser tuberosity is a slight knob on the medial
side of the humeral head. Both the greater and lesser
tuberosities are rugose, which indicates strong
muscle attachments. A tightly rounded bicipital
groove separates the greater tuberosity and the
intermediate tubercle. The intermediate tubercle is
Figure 31. Atlas of ETMNH 609. Views: A, dorsal; B, anterior; C, left lateral; D, posterior. Abbreviations:
CAAS, caudal articular surface; CRAS, cranial articular surface; DA, dorsal arch; DTB, dorsal tubercle;
LVF, lateral vertebral foramen; NC, neural canal; TVF, transverse foramen; TVP, transverse process; VA,
ventral arch; VTB, ventral tubercle. Scale bar = 10 cm.
218 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
not as prominent as that seen in Equus and, for that
reason, was not considered to be present in rhinos
by Hermanson and MacFadden (1992). It is being
considered as a feature here because it is distinct
from the greater and lesser tuberosities and, within
rhinos, Teleoceras has a large intermediate tubercle
(Mihlbachler, 2013, pers. comm.).
In medial view, rugose bone extends from the
lesser tuberosity almost to the medial epicondyle.
In lateral view, the deltoid tuberosity is distal to the
greater tuberosity and, though the deltoid tuberos-
ity is small, it is a rugose projection that is directed
posteriorly. A pronounced humeral crest originates
at the deltoid tuberosity and curves distomedially.
Anterodistally, a larger, medial coronoid fossa
and a smaller, lateral radial fossa are proximal to
the trochlea and capitulum, respectively, and are
divided by a very slight ridge. The wide trochlea
extends more proximally than the narrow capitu-
lum, giving the appearance of a rotated articu-
lar surface. Articular surfaces of the trochlea and
capitulum curve around the distal end, narrow, and
merge before terminating at the distal edge of the
olecranon fossa. Epicondyles are robust, and the
Figure 32. Axis of ETMNH 609. Views: A, dorsal; B, left lateral; C, anterior; D, posterior. Abbreviations:
CAN, caudal notch; CEN, centrum; CRN, cranial notch; NC, neural canal; OP, odontoid process; PRZ,
prezygapophyses; POZ, postzygapophyses; TVF, transverse foramen; TVP, transverse process. Scale bar
= 10 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 219
medial epicondyle is relatively slender in contrast
to the expanded lateral epicondyle. The epicon-
dyles form the sides of the olecranon fossa, which
is a deep, rounded depression that is proximally
open to the diaphysis. From the lateral epicondyle,
the epicondylar crest extends proximally to the
midpoint of the posterior diaphysis.
Ulna.—At the proximal end, the olecranon
process is robust with heavy rugosities and numer-
ous foramina (Fig. 42). A prominent anconeal pro-
cess slants laterally at its proximal point, which
is marked with a ‘V’-shaped depression. A broad
trochlear notch slants laterally at its proximal end.
Two articular processes extend from the distal
trochlear notch; the medial of which is wider and
longer than the lateral. A deep, rugose radial notch
is present between the medial and lateral processes
of the trochlear notch. The articular surface of the
trochlear notch has a slight concave curvature for
articulation with the humerus; the radius acts as a
stabilizer for this joint.
Ulnar diaphyses are triangular in cross
section with the apex along the posterior surface.
The ulna has its narrowest point at its proximal
Figure 33. Fourth cervical vertebra of ETMNH 609. Views: A, dorsal; B, anterior; C, right lateral; D,
posterior. Abbreviations: APR, anterior prominence; CEN, centrum; NC, neural canal; NS, neural spine;
POZ, postzygapophyses; PRZ, prezygapophyses; TVF, transverse foramen; TVP, transverse process.
Scale bar = 10 cm.
220 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
Figure 34. Sixteenth thoracic vertebra of ETMNH 609. Views: A, dorsal; B, right lateral; C, anterior; D,
posterior. Abbreviations: AFAR, articular fossa for anterior rib; AFPR, articular fossa for posterior rib;
CAN, caudal notch; CEN, centrum; CF, costal fossa; DA, dorsal arch; NC, neural canal; NS, neural spine;
POZ, postzygapophyses; PRZ, prezygapophyses; TVP, transverse process. Scale bar = 10 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 221
end just distal to the radial notch and broadens
distally. At the distal end, the diaphysis narrows
to form the styloid process, which articulates
with the cuneiform and the radius. In distal view,
the articular surface for the cuneiform is slanted
from anterolateral to posteromedial with a central
concavity that extends parallel to the slant of the
facet. On the proximomedial surface of the styloid
process, a small facet extends along the medial
edge of the ulna providing a point of articulation
with the radius.
Radius.—The neck of the radius narrows
more on the lateral side to form a diaphyseal curve
but is only slightly narrowed on the medial side
(Fig. 43). There is a small anteroposterior ridge
between the two proximal articular surfaces for
the capitulum and trochlea of the humerus. This
ridge is offset laterally creating a larger medial
articular facet for the trochlea. Also proximally,
on the posterior surface, there is a rugose site for
attachment to the ulna. A triangular articular surface
on the proximolateral side is slightly depressed for
articulation with the corresponding facet on the
anterior surface of the ulna. On the proximoanterior
surface of the radius, there is a radial tuberosity that
is rugose but not depressed on the GFS specimens;
this feature can form a pronounced fossa on some
Teleoceras.
Distally, there is a triangular area of rugose
bone on the posterolateral surface that ts into the
Figure 35. Third lumbar vertebra of ETMNH 609. Views: A, dorsal; B, anterior; C, right lateral; D,
posterior. Abbreviations: CEN, centrum; NC, neural canal; NS, neural spine; PRZ, prezygapophyses;
POZ, postzygapophyses; TVP, transverse process. Scale bar = 10 cm.
222 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
corresponding area of the ulna. A small, rounded
articular facet is along the posterolateral edge for
articulation with the ulna. Medially adjacent to
that facet is a narrow articular surface for articula-
tion with the cuneiform. Two additional articular
facets are on the very distal surface and are sepa-
rated by a ridge as they slant from anterolateral to
posteromedial. A smaller lateral articular surface is
depressed on the posterior portion for articulation
with the lunar and the more rounded medial articu-
lar surface is depressed on the anterior portion for
articulation with the scaphoid; together, these form
a continuous depression across the slant of the
articular surfaces. No remnant of a styloid process
is present on the distal radius.
Scaphoid.—The scaphoid is the largest of the
carpal bones (Figs. 44, 45). Proximally, there is a
concave, rounded articular surface for the radius.
The medial corner of this surface folds over its
raised point to form an articular surface extension.
Where the lateral corner is raised, it forms an edge
with an anteroproximal articular surface for the
lunar. Posterior to the radial facet is the rugose pos-
terior process with a second, round articular surface
for the lunar on the lateral side. On the posterior
side of the lateral extension, there is a third, round
articular surface for the lunar. This facet folds over
into the triangular laterodistal articular surface for
the magnum. A raised ridge is formed by this lat-
erodistal and the mediodistal articular surfaces.
The mediodistal articular surface for the trapezoid
is saddled over the distal surface and extends on
both the anterior and posterior surfaces.
Lunar.—Overall, the lunar is anteroposte-
Figure 36. Sacrum of ETMNH 609. Views: A, dorsal; B, anterior; C, right lateral; D, posterior.
Abbreviations: CAN, caudal notch; CEN, centrum; CRN, cranial notch; NC, neural canal; NS, neural
spine; PRZ, prezygapophyses; SF1–3, sacral foramina 1–3; SV1–4, sacral vertebrae 1–4; SW, sacral wing.
Scale bar = 10 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 223
riorly elongate and mediolaterally narrow (Figs.
44, 46). Most of the articular surfaces are on the
anterior two-thirds of the lunar as the posterior
one-third forms a rugose process. On the proxi-
momedial side of the process, there is an articular
surface that is one of the three points of articula-
tion with the scaphoid. Proximally, the lunar has
a large, convex articular surface for articulation
with the radius. Posteriorly, this articular surface
slopes distally onto the lunar process, whereas the
anterior portion slopes along the anterior surface.
Distally, the lunar has two concave articular sur-
faces joined at a slightly elevated ridge. The medial
facet is a small tear-drop situated more posteriorly
for articulation with the magnum. The lateral facet
is posteriorly square and anteriorly ared, and it
articulates with the unciform. On the medial side,
there are two additional articular surfaces for the
scaphoid. The proximal of these is elongate antero-
Figure 37. Third caudal vertebra of ETMNH 609. Views: A, dorsal; B, right lateral; C, anterior; D,
posterior. Abbreviations: CEN, centrum; NC, neural canal; NDN, neural dorsal notch; NS, neural spine;
TVP, transverse process. Pre- and post-zygapophyses are not visible in this gure. Scale bar = 10 cm.
Figure 38. Sternebrae of ETMNH 609. Scale bar
= 10 cm.
Figure 39. Ribs of ETMNH 601 showing pathology.
Scale bar = 10 cm.
224 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
posteriorly, and the distal one is proximally domed
and distally square. On the lateral side, there are
also two articular surfaces for articulation with the
cuneiform. The proximal of these is oval, and the
distal one is thin and oblong.
Cuneiform.—Proximodistal and anteropos-
terior axes of the cuneiform are long, whereas the
mediolateral axis is short (Figs. 44, 47). There is
rugose bone extending anteroposteriorly on the
distal portion of the lateral side. A proximal articu-
lar surface is saddle-like for articulation with the
styloid process of the ulna. Laterally, this articular
surface curves distally, and medially, it terminates
at a ridge with a rectangular articular surface for
the lunar. A square articular surface with a rounded
anterolateral corner is present on the distal end of
the cuneiform for articulation with the unciform.
Medially, this ulnar articular surface folds proxi-
mally and creates a small, domed articular surface
for the lunar. On the posterior side, an oblong artic-
ular surface is present for articulation with the pisi-
form. This articular surface forms a lateral ridge as
it joins the lateral portion of the proximal articular
surface.
Pisiform.—The pisiform appears to be
pinched mediolaterally because it curves medi-
Figure 40. Right scapula of ETMNH 609. Views: A, lateral; B, distal. Abbreviations: CCP, coracoid
process; CDB, caudal border; CLE, craniolateral edge; CRB, cranial border; GF, glenoid fossa; ISF,
infraspinous fossa; SCN, scapular neck; SCS, scapular spine; SSF, supraspinous fossa; ST, spinous tuber;
VBB, vertebral border. Scale bar = 10 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 225
Figure 41. Right humerus of ETMNH 609. Views: A, anterior; B, posterior; C, medial; D, lateral; E, proximal; F, distal. Abbreviations: AH,
articular head; BCG, bicipital groove; CAP, capitulum; CF, coronoid fossa; HCT, humeral crest; DT, deltoid tuberosity; ECC, epicondylar
crest; GR1, groove one; GR2, groove two; GTC, greater tuberosity convexity; GTS, greater tuberosity summit; IMT, intermediate tubercle;
LEC, lateral epicondyle; LTC, lesser tuberosity convexity; LTS, lesser tuberosity summit; MEC, medial epicondyle; NF, nutrient foramen;
OF, olecranon fossa; PD, proximal depression; RF, radial fossa; TRO, trochlea. Scale bar = 10 cm.
226 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
Figure 42. Right ulna of ETMNH 609. Views: A, anterior; B, posterior; C, medial; D, lateral; E, proximal; F, distal. Abbreviations: AP,
anconeal process; ARR, articular rugose bone for radius; ASC, articular surface for cuneiform; ASR1–2, articular surfaces for radius 1–2;
LAP, lateral articular process; MAP, medial articular process; OP, olecranon process; RN, radial notch; SP, styloid process; TN, trochlear
notch. Scale bar = 10 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 227
Figure 43. Right radius of ETMNH 609. Views: A, anterior; B, posterior; C, medial; D, lateral; E, proximal; F, distal. Abbreviations:
ASU1–3, articular surfaces for the ulna 1–3; ASC, articular surface for the capitulum; ASL, articular surface for the lunar; ASS, articular
surface for the scaphoid; AST, articular surface for the trochlea; CP, radial coronoid process; NK, radial neck; RCT, radial crest; RTB, radial
tuberosity. Scale bar = 10 cm.
228 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
ally and ares posteriorly (Figs. 44, 48). An ante-
rior articular surface for the cuneiform is round
proximally and square distally. ETMNH 601 has
an additional small, round anterolateral articular
surface for the ulna that does not occur in ETMNH
609.
Trapezium.—The trapezium is a small,
rugose bone with a ‘V’-shape pointed distally
(Figs. 44, 49). An oval articular surface for the
trapezoid is present on the lateral side. ETMNH
601 has a distally extended articular surface for a
slight articulation with the second metacarpal.
Trapezoid.—A rugose prominence occurs on
the anterior surface (Figs. 44, 50). The proximal
articular surface for the scaphoid is square with a
convexly rounded medial edge and is depressed
mediolaterally. At the posteromedial corner of this
facet, it forms a ridge with a round, medial articular
surface for the trapezium. Distally, the trapezium
articular surface folds laterally into the convex,
ovate distal articular surface for the second meta-
carpal. Laterally, this distal articular surface forms
an edge with the lateral kidney-shaped articular
surface for the magnum.
Magnum.—The magnum is narrower across
the mediolateral axis than the anteroposterior axis
(Figs. 44, 51). Anteroproximally, there is an articu-
lar surface for the scaphoid that is triangular with
Figure 44. Articulated carpal bones of ETMNH 609 in anterior view. Abbreviations: CUN, cuneiform;
LUN, lunar; MAG, magnum; SCA, scaphoid; TRD, trapezoid; TRM, trapezium; UNC, unciform. The
pisiform is not visible in this view. Scale bar = 10 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 229
an anterior straight edge and posterior point that is
laterally raised. This raised portion forms a ridge
with the triangular posteroproximal articular sur-
face, which is saddled over a proximally raised pro-
cess, for articulation with the lunar. On the medial
surface, there is a kidney-shaped articular surface
that articulates with the trapezoid and forms an
edge with the anteroproximal facet. Along its distal
edge, this articular surface contacts a small, rect-
angular articular surface for the second metacar-
pal. One articular surface for the third metacarpal
covers most of the distal surface of the magnum.
Posteriorly, this articular surface extends along a
small distal process that mirrors the proximal pro-
cess. This facet is slightly curved anteriorly and
has a straight medial edge with the second meta-
carpal facet. On the lateral side, there is another
kidney-shaped articular surface for the unciform.
The magna from the GFS lack a posterior process
resembling those discussed by Harrison and Man-
ning (1983).
Unciform.—All of the articular surfaces are
on the anterior portion of the unciform and are dis-
tolaterally curved (Figs. 44, 52). The posterior por-
tion of the unciform consists of a rugose process
that can be variable within a population as demon-
strated by Harrison and Manning (1983), but it is
consistent within the limited sample from the GFS.
Two articular surfaces meet at a ridge on the proxi-
mal side of the anterior portion. The proximolat-
eral articular surface for the cuneiform is slightly
convex anteroposteriorly and comes to a rounded
point on the lateral side. The proximomedial artic-
ular surface is round, longer anteroposteriorly, and
Figure 45. Right scaphoid of ETMNH 609. Views: A, anterior; B, posterior; C, proximal; D, distal; E,
medial; F, lateral. Abbreviations: ASL1–3, articular surfaces for lunar 1–3; ASM, articular surface for
magnum; ASR, articular surface for radius; AST, articular surface for trapezoid; PP, posterior process.
Scale bar = 5 cm.
230 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
articulates with the lunar. A second medial articular
surface is distal to the lunar facet and is ‘C’-shaped
for articulation with the magnum. On the distal sur-
face, articular facets are present for the third, fourth,
and, on ETMNH 601, fth metacarpals. The more
medial third metacarpal and the lateral fourth meta-
carpal share the articular surface without a dividing
ridge; however, there is an indicative line formed
by wear. Overall, the articular surface is triangu-
lar with a small convexity along the medial edge
near where it contacts the medial articular surface
for the magnum. This lateral indentation articulates
with the fth metacarpal or the proximal expansion
present on some fourth metacarpals.
Second Metacarpal.—Both medial and lat-
eral edges are slightly curved medially so the sides
appear pinched anteroposteriorly (Fig. 53). There is
a slight posterior ridge just medial to the midline of
the bone that extends from proximal to distal and,
at the posterodistal facets, matches with the inter-
mediate relief. On the proximal end, there are three
primary articular surfaces. A roughly square medial
articular surface for the trapezoid is the largest and
has a slight depression in the middle. The lateral
edge of this facet is raised to form a ridge with the
rectangular proximomedial articular surface for the
Figure 46. Right lunar of ETMNH 609. Views: A, anterior; B, posterior; C, proximal; D, distal; E, medial;
F, lateral. Abbreviations: ASC1–2, articular surfaces for cuneiform 1–2; ASM, articular surface for
magnum; ASR, articular surface for radius; ASS1–3, articular surfaces for scaphoid 1–3; ASU, articular
surface for unciform; LP, lunar process. Scale bar = 5 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 231
Figure 47. Right cuneiform of ETMNH 609. Views: A, anterior; B, posterior; C, proximal; D, distal;
E, medial; F, lateral. Abbreviations: ASL1–2, articular surfaces for lunar 1–2; ASP, articular surface for
pisiform; ASUL, articular surface for ulna; ASUN, articular surface for unciform. Scale bar = 5 cm.
Figure 48. Right pisiform of ETMNH 609. Views:
A, anterior; B, dorsal; C, lateral. Abbreviations:
ASC, articular surface for cuneiform. Scale bar
= 5 cm.
232 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
Figure 49. Right trapezium of ETMNH 609. Views: A, proximal; B, distal; C, medial; D, lateral.
Abbreviation: AST, articular surface for trapezoid. Scale bar = 1 cm.
Figure 50. Right trapezoid of ETMNH 609. Views: A, anterior; B, posterior; C, proximal; D, distal; E,
medial; F, lateral. Abbreviations: ASM, articular surface for magnum; ASMC2, articular surface for second
metacarpal; ASS, articular surface for scaphoid; AST, articular surface for trapezium. Scale bar = 5 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 233
magnum, which slopes distally and laterally from
the ridge. At the distal edge, this facet folds into the
lateral-most articular surface of the proximal end.
This lateral articular surface for the third meta-
carpal is rectangular. At the distal end, the ante-
rior articular surface for the proximal phalanx is
smooth and, though the lateral edge is parallel to
the axis of the bone, the medial edge curves later-
ally creating a half-dome shape. On the posterior
articular surface, two facets are separated by the
intermediate relief. Both facets are oval with slight
depressions along their midlines, are slanted from
proximomedial to distolateral, and each articulates
with one sesamoid.
Third Metacarpal.—On the anterior surface
of the proximal end, there are two rugose knobs
that serve as sites of muscle attachment (Fig. 54).
Similar rugosities are on the posterior surface as
well. In posterior view, a nutrient foramen is pres-
ent at the midpoint of the diaphysis along a poste-
rior ridge that separates a pair of depressions prox-
imal to the distal articular surface. These depres-
sions are not as pronounced as those seen in other
species of Teleoceras. On the medial and lateral
sides of the bone, there are proximal rectangular
articular surfaces for the second and fourth meta-
Figure 51. Right magnum of ETMNH 609. Views: A, anterior; B, posterior; C, proximal; D, distal; E,
medial; F, lateral. Abbreviations: ASL, articular surface for lunar; ASMC2–3, articular surfaces for sec-
ond and third metacarpals; ASS, articular surface for scaphoid; AST, articular surface for trapezoid; ASU,
articular surface for unciform. Scale bar = 5 cm.
234 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
carpals, respectively. A triangular articular surface
for the magnum is on the medial side of the proxi-
mal end and has a concavity at the narrow posterior
end. The lateral proximal articular surface for the
unciform is medially domed with a straight lateral
edge and a pinched posterior point. Distally, the
anterior articular surface for the proximal phalanx
of the third digit is smooth and domed proximally.
Posteriorly, an intermediate relief divides the distal
articular surface into two oval facets for articula-
tion with the two sesamoids.
Fourth Metacarpal.—Along the diaphysis,
the narrower lateral side is more concave than the
rugose medial side (Fig. 55). Both the proximal
and the distal ends curve further posteriorly than
the diaphyseal area giving the appearance that the
midsection is depressed. Two articular surfaces are
on the proximal end of the fourth metacarpal. Medi-
ally, there is a rectangular articular surface for the
third metacarpal. The proximal edge of this facet
forms a ridge with the medial edge of the proximal
articular surface. This proximal articular surface for
the unciform is the larger of the two and is indented
along the lateral edge. Posteriorly, it folds over a
raised portion that forms a tight articulation with
the unciform. On ETMNH 601, there is an articular
notch lateral to this facet where the fth metacarpal
articulates; however, on ETMNH 609, a remnant
Figure 52. Right unciform of ETMNH 609. Views: A, anterior; B, posterior; C, proximal; D, distal; E,
medial; F, lateral. Abbreviations: ASC, articular surface for cuneiform; ASL, articular surface for lunar;
ASM, articular surface for magnum; ASMC3–4, articular surfaces for third and fourth metacarpals; UNP,
unciform process. Scale bar = 5 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 235
Figure 53. Right second metacarpal of ETMNH 609. Views: A, anterior; B, posterior; C, medial; D, lateral;
E, proximal; F, distal. Abbreviations: ASM, articular surface for magnum; ASMC3, articular surface for
third metacarpal; ASPP2, articular surface for proximal phalanx of the second digit; ASS1–2, articular
surfaces for sesamoids 1–2; AST, articular surface for trapezoid; IR, intermediate relief; PR, posterior
ridge. Scale bar = 5 cm.
Figure 54. Right third metacarpal of ETMNH 609. Views: A, anterior; B, posterior; C, medial; D, lateral;
E, proximal; F, distal. Abbreviations: ASM, articular surface for magnum; ASMC2, articular surface for
second metacarpal; ASMC4, articular surface for fourth metacarpal; ASPP3, articular surface for proximal
phalanx of third digit; ASS1–2; articular surface for sesamoids 1–2; ASU, articular surface for unciform;
IR, intermediate relief; NF, nutrient foramen; PR, posterior ridge. Scale bar = 5 cm.
236 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
of the fth metacarpal is fused to the fourth meta-
carpal in place of the notch. At the distal end, the
anterior articular surface for the proximal phalanx
is smooth and proximally domed with only a slight
lateral curvature. Two facets are on the posterior
surface and are separated by an intermediate relief
that slants from proximomedial to distolateral cre-
ating slanted facets for articulation with the two
sesamoids.
Fifth Metacarpal.—Each manus of ETMNH
601 has a fth metacarpal (Fig. 56) that was rst
described by Wallace (2006). A proximal articular
surface for the unciform has a posterior convex
fold. There is medial rugose bone that articulates
with a proximolateral depression on the fourth
metacarpal. On ETMNH 609 and 8271, the fourth
metacarpals have expanded lateral knobs, which
are believed to be the remnants of the fth metacar-
pals. Neither the isolated nor the fused fth meta-
carpals have evidence of a distal articular surface
for a proximal phalanx.
Though similar in morphology, metacarpals
are noticeably larger than metatarsals (Fig. 57).
Distal to the metacarpals, each digit consists of
three phalanges and two sesamoids. Phalanges and
sesamoids of the manus and pes are nearly indis-
tinguishable except for by size (Fig. 58), so a com-
bined description will be provided following the
description of the hind limb.
hinD limb
Innominate.—It is difcult to differenti-
ate the three bones—ilium, ischium, and pubis—
that make up each innominate due to the degree
of fusion (Fig. 59). The acetabulum is round with
the acetabular incision on the lateral edge of the
obturator foramen. There is a small fossa on the
articular surface of the acetabulum. The ilium is the
largest of the innominate bones and expands into
a broad wing. Laterally, the iliac wing is smooth,
but the medial iliac wing is rugose for articulation
with the sacrum. The iliac crest is rounded at the
dorsocranial spine and makes a nearly straight edge
to the ventrocranial spine. A sciatic eminence is
prominent on the dorsocranial spine and the greater
Figure 55. Right fourth metacarpal of ETMNH 609. Views: A, anterior; B, posterior; C, medial; D, lateral;
E, proximal; F, distal. Abbreviations: ASMC3, articular surface for third metacarpal; ASPP4, articular
surface for proximal phalanx of fourth digit; ASS1–2, articular surfaces for sesamoids 1–2; ASU, articular
surface for unciform; IR, intermediate relief; RMC5, remnant of fth metacarpal. Scale bar = 5 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 237
sciatic notch is deep. A thin, smooth ischium forms
the symphysis, which is small relative to the over-
all size of the innominate. The ischial arch occurs
between this symphysis and the rugose ischiatic
tuberosity. There is no evidence of an ilio-pubic
eminence between the ilium and the pubis, which
has a broad body and slender branches.
Femur.—The diaphysis is slightly curved in
the parasagittal plane (Fig. 60). The posterior sur-
face of the femur is nearly attened, but the ante-
rior surface is more rounded. At the proximal end,
there is a minimal trochanteric fossa along the pos-
terior edge of the greater trochanter. A round artic-
ular head extends only minimally proximal to the
greater trochanter. Along the medial edge, the head
forms a lip that overlies the suture line. There is no
obvious fovea capitis on the femoral head. A shal-
low depression is the only evidence of a femoral
neck between the head and the greater trochanter.
There is a blunt greater trochanter without a denite
summit and with only a minimal crest at the latero-
distal point. There is an elongate, rugose lesser tro-
chanter on the medial surface that does not extend
more medially than the femoral head. An elongate
third trochanter is on the lateral surface but does
not extend as far laterally as the greater trochanter.
Figure 56. Right fth metacarpal of ETMNH 601. Views: A, anterolateral showing articulation with
fourth metacarpal; B, dorsal; C, medial; D, lateral. Abbreviations: ASU, articular surface for unciform;
MC4, fourth metacarpal; MR, medial rugose bone. Scale bar = 5 cm.
238 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
lear tubercle along the diaphysis to the head. In
anterior view, the more prominent medial troch-
lear tubercle is also more rounded compared to the
smaller and more angular lateral trochlear tubercle.
It is possible that this medial trochlear tubercle
acted as a locking mechanism as found in derived
equids (Hermanson and MacFadden, 1996). On the
posterodistal surface, a larger lateral condyle slants
slightly compared to the smaller medial condyle,
which is more aligned with the diaphyseal axis. A
deep intercondylar fossa extends medially and lat-
erally beneath the edges of the articular condyles.
Both epicondyles have large muscle scars on the
outer surface. Most femoral muscle attachments are
well-dened, especially the supracondylar fossa on
the posterior surface just proximal to the condyles.
Patella.—Patellae are massive, rugose bones
that articulate with the femoral trochlear tubercles
(Fig. 61). A distinct point is formed by the apex at
the distal end, but the base forms a rounded angle at
the proximal end. The base does not extend much
further proximally than the posterior articular sur-
face does. This articular surface covers nearly the
entire posterior surface and has two convexities
The third trochanter is reduced among rhinocero-
tids but is larger than those seen in most other spe-
cies of Teleoceras.
Distally, medial and lateral trochlear tuber-
cles are present on the anterior surface and are sep-
arated by a trochlear groove. There is a pronounced
femoral ridge that extends from the medial troch-
Figure 57. Right metapodials of ETMNH 609 in anterior view. A, metacarpals; B, metatarsals. Scale bar
= 5 cm.
Figure 58. Right phalanges of third digits of
ETMNH 609. Left, front phalanges; Right, hind
phalanges. A, proximal phalanges; B, medial
phalanges; C, distal phalanges. Scale bar = 5 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 239
Figure 59. Left innominate of ETMNH 609. Views: A, anterodorsal; B, anteroventral. Abbreviations:
ACE, acetabulum; ACI, acetabular incision; DCS, dorsocranial spine; GSN, greater sciatic notch; ILC,
iliac crest; ILW, iliac wing; IST, ischiatic tuberosity; OBF, obturator foramen; SYM, symphysis; VCS,
ventrocranial spine. Scale bar = 10 cm.
that extends from proximal to distal for articulation
with the femoral trochlear tubercles. A rounded lat-
eral angle is present but not pronounced. In con-
trast, the medial angle is a well-dened prominence
that forms a distomedial point.
Tibia.—The proximal end is larger than the
distal and, for articulation with the femur, it has
two large articular surfaces separated by a minimal
popliteal notch on the posterior surface (Fig. 62).
The lateral articular surface is a rounded triangle
whereas the medial articular surface is smaller,
more rounded, and more centrally depressed than
the lateral articular surface. A cranial intercondy-
lar area is present between the anterior portions
of the medial and lateral articular surfaces. A nar-
row depression—the central intercondylar area—is
bordered by the lateral and medial intercondylar
eminences to separate the lateral articular surface
from the medial articular surface and. There is also
a smaller, atter caudal intercondylar area between
the posterior portions of the articular surfaces.
Between the medial and lateral tibial tuberosities,
there is a shallow tibial tuberosity groove. Though
the medial tibial tuberosity is slightly rugose and
aligned with the diaphysis, the lateral tibial tuberos-
ity is more prominent, more rugose, and protrudes
laterally from the diaphysis. Proximolaterally,
there is a bular articular surface that is shaped like
an upside-down teardrop as seen on ETMNH 609.
Rather than being smooth as most articular sur-
faces are, this is rugose for a tight articulation that
becomes fused with age as seen on ETMNH 601.
In cross-section, the diaphysis is triangular as
the tibial crest extends for nearly the entire length
of the bone. The medial side of the diaphysis is
nearly straight, but the lateral side is concave with
a slight projection near the midpoint of the diaphy-
sis. Distally, there is a parallelogram-shaped articu-
240 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
Figure 60. Right femur of ETMNH 609. Views: A, anterior; B, posterior; C, medial; D, lateral; E, proximal; F, distal. Abbreviations: AH,
articular head; FRD, femoral ridge; GRT, greater trochanter; ICF, intercondylar fossa; LCD, lateral condyle; LEC, lateral epicondyle; LET,
lesser trochanter; LTT, lateral trochlear tubercle; MCD, medial condyle; MEC, medial epicondyle; MTR, medial trochlear ridge; MTT,
medial trochlear tubercle; NK, neck; TF, trochanteric fossa; TG, trochlear groove; THT, third trochanter. Scale bar = 10 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 241
lar surface for the astragalus. Depressions for the
astragalar trochlea are slanted from anterolateral to
posteromedial and are separated by a raised ridge
that appears to be pinched anteroposteriorly. Pos-
teromedially to this articular surface is the medial
malleolus, which is the distal-most point of the
tibia. On the lateral surface, there is a small, domed
articular surface for the bula that contacts the
astragalar facet along its distal edge. A triangle of
rugose bone extends proximal to the bular facet to
form a tighter articulation with the bula. A ridge
connects the proximal and distal bular facets as it
runs the length of the diaphysis, including the lat-
eral projection that matches the medial protuber-
ance of the bula.
Fibula.—Fibulae have rugose ends with an
Figure 62. Right tibia of ETMNH 609. Views: A, anterior; B, posterior; C, medial; D, lateral; E, proximal;
F, distal. Abbreviations: ADP, anterodistal process; ASA, articular surface for astragalus; ASF1–2, articular
surfaces for bula 1–2; CDIA, caudal intercondylar area; CRIA, cranial intercondylar area; CTIA, central
intercondylar area; LASF, lateral articular surface for femur; LIE, lateral intercondylar eminence; LTT,
lateral tibial tuberosity; MASF, medial articular surface for femur; MIE, medial intercondylar eminence;
MM, medial malleolus; MTT, medial tibial tuberosity; PN, popliteal notch; TCT, tibial crest; TTG, tibial
tuberosity groove. Scale bar = 10 cm.
Figure 61. Left patella of ETMNH 609 ipped to
appear as right. Views: A, posterior; B, anterior.
Abbreviations: AP, apex; BA, base; CV1 and CV2,
patellar convexity 1 and 2; MA, medial angle; PAS,
posterior articular surface. Scale bar = 5 cm.
242 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
distal to a corresponding projection on the lateral
side of the tibial diaphysis. The bulae of ETMNH
601 are proximally fused to the tibiae as seen in
some species of Teleoceras (Prothero, 2005).
Calcaneum.—The calcaneum is the largest
of the tarsal bones (Figs. 64, 65). It is important
to note that the articular surfaces of the calcanea
display a large amount of variation in their size and
shape. Heavily rugose bone covers the distal end of
the calcaneal tuber and forms a ridge along the lat-
eral surface of the diaphysis, which appears com-
pressed mediolaterally. On the medial surface, the
sustentaculum is prominent and rugose with only
a slight tendon groove. A dorsal, roughly rounded
articular surface for the astragalus is present on
the sustentaculum. Lateral to the sustentaculum is
a second articular surface for the astragalus. This
facet is ovate, slants toward the sustentaculum,
and is depressed along a mediolateral fold. The lat-
eral edge of this articular surface folds over into a
variably-shaped bular articular surface. There is
a small knob of rugose bone lateral to the bular
facet. On the medial side of the proximal process,
there is a small facet that articulates with the astrag-
alus. This facet folds into the oval articular surface
for the cuboid on the plantar side of the calcaneum.
Astragalus.—The proximal side of the
astragalus forms a trochlea that provides the articu-
lar surface for the tibia (Figs. 64, 66). The larger,
lateral portion of the trochlea extends more proxi-
mally than the smaller, medial portion. A wide
trochlear groove separates the lateral and medial
portions of the trochlea. The articular surface of
the lateral trochlea folds posterolaterally to form
a second proximal articular surface that, with the
calcaneum, contributes to an articular surface for
the bula. The astragalar base is distal to the troch-
lea and has two articular surfaces separated by a
raised ridge. Medially, there is a square surface
with rounded medial corners for articulation with
the navicular. The lateral articular surface for the
cuboid is rectangular with the long axis oriented
anteroposteriorly, is nearly at at the level of the
ridge formed with the medial articular surface, and
folds proximolaterally. On the posterior surface of
the astragalus, there is an oval articular surface for
anteroposteriorly compressed proximal end of the
diaphysis and a triangular distal end of the diaphysis
with rounded angles (Fig. 63). The proximal artic-
ulation site for the tibia is shaped like an upside-
down teardrop, whereas the distal articulation site
is semi-circular. A small, round articular surface is
present on the distal lateral malleolus for articula-
tion with the astragalus. It is continuous with the
corresponding distolateral articular facet on the
tibia. A ridge curves from the proximal posterolat-
eral articulation site to the distolateral articulation
site. Along this ridge, there is a small protuberance
that, when articulated with the tibia, is only slightly
Figure 63. Left bula of ETMNH 609 ipped
to appear as right. Views: A, lateral; B, medial.
Abbreviations: ASA, articular surface for
astragalus; AST1–2, articular surfaces for tibia
1–2; LML, lateral malleolus. Scale bar = 10 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 243
Figure 64. Articulated right tarsal bones of ETMNH 609 in anterior view. Abbreviations: AST, astragalus;
CAL, calcaneum; CUB, cuboid; ECC, ectocuneiform; NAV, navicular. The mesocuneiform and
entocuneiform are not visible in this view. Scale bar = 10 cm.
244 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
Figure 65. Right calcaneum of ETMNH 609. Views: A, dorsal; B, ventral; C, medial; D, lateral; E, distal.
Abbreviations: AP, anterior process; ASA1–3, articular surfaces for astragalus 1–3; ASC, articular surface
for cuboid; ASF, articular surface for bula; CTB, calcaneal tuber; SUS, sustentaculum; TG, tendon
groove. Scale bar = 5 cm.
Figure 66. Left astragalus of ETMNH 609 ipped to appear as right. E and F are the right astragalus of the
same specimen. Views: A, anterior; B, posterior; C, proximal; D, distal; E, medial; F, lateral. Abbreviations:
ASC, articular surface for cuboid; ASF, articular surface for bula; ASN, articular surface for navicular;
ASS, articular surface for sustentaculum; AST, articular surface for tibia; BAS, base; DASCL, distal
articular surface for calcaneum; DR, distal ridge; PASCL, proximal articular surface for calcaneum; TRG,
trochlear groove; TRO, trochlea. Scale bar = 5 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 245
the sustentaculum of the calcaneum that is posi-
tioned superior to the midpoint of the base and
inferior to the trochlear groove. Laterally, there is
a large, oblong articular surface for the calcaneum
proximolateral to the astragalar base.
Navicular.—In general, the navicular is a
square bone and is compressed proximodistally
(Figs. 64, 67). One articular surface for the astraga-
lus covers nearly the entire proximal side. This
surface slants from the posteromedial corner to the
anterolateral corner. At its anterolateral corner, this
articular surface folds into a small, lateral articu-
lar surface for the cuboid. There is another small,
round articular surface on the posterolateral side
that forms a second articulation with the cuboid.
The two lateral articular surfaces are separated by
a depression, but both form an edge with the distal
articular surface. There is a small medial protuber-
ance on the posterior surface with a small, round,
distal articular surface for the entocuneiform. Dis-
tally, the smaller, round, medial articular surface
for the mesocuneiform is separated from the larger,
triangular, lateral articular surface for the ectocu-
neiform by a slight ridge. There is a concavity on
the lateral edge of the ectocuneiform articular sur-
face that corresponds to the depression between the
lateral cuboid articular surfaces.
Cuboid.—This bone is compressed proxi-
modistally but is elongated anteroposteriorly (Figs.
64, 68). A nearly triangular portion extends into a
posterior, rugose process with a distal curvature.
On the medial side of the posterior process, there
Figure 67. Right navicular of ETMNH 609. Views: A, anterior; B, posterior; C, proximal; D, distal; E,
medial; F, lateral. Abbreviations: ASA, articular surface for astragalus; ASC1–2, articular surfaces for
cuboid 1–2; ASEC, articular surface for ectocuneiform; ASEN, articular surface for entocuneiform; ASM,
articular surface for mesocuneiform; MPT, medial process. Scale bar = 5 cm.
246 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
is a single anteromedial articular surface divided
into two semi-circular facets. The proximal sur-
face articulates with the navicular and the distal
articulates with the ectocuneiform. Two articular
surfaces are present on the proximal surface of the
anterior portion; both are triangular and are divided
by a ridge. The medioproximal articular surface
articulates with the astragalus and the lateroproxi-
mal articular surface articulates with the calca-
neum. A small, proximal articular surface for the
navicular is on the medial surface of the anterior
portion. Distal to this facet is a domed articular sur-
face for articulation with the ectocuneiform. This
facet folds onto the distal surface into two artic-
ular surfaces that are separated by a slight ridge.
The smaller medial articular surface for the third
metatarsal is a slender rectangle with the long axis
oriented anterolateral to posteromedial. Laterally,
a larger, triangular articular surface is present for
articulation with the fourth metatarsal.
Entocuneiform.—This is a small, rugose
bone that curves distolaterally (Fig. 69). An oval
anterolateral surface articulates with the mesocu-
neiform and a small round proximal surface articu-
Figure 68. Right cuboid of ETMNH 609. Views: A, anterior; B, posterior; C, proximal; D, distal; E,
medial; F, lateral. Abbreviations: ASA, articular surface for astragalus; ASC, articular surface for cuboid;
ASN1–2, articular surfaces for navicular 1–2; ASE1–2, articular surface for ectocuneiform 1–2; ASMT3,
articular surface for third metacarpal; ASMT4, articular surface for fourth metacarpal. Scale bar = 5 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 247
lates with the navicular.
Mesocuneiform.—A rugose knob is present
on the anteromedial face of the mesocuneiform
(Fig. 70). The mesocuneiform proximally articu-
lates with the navicular and distally with the sec-
ond metatarsal. From the distal articular surface,
the lateral edge folds proximally into an articular
surface for the ectocuneiform. Also from the dis-
tal articular surface, the posteromedial edge folds
proximally into an articular surface for the entocu-
neiform. Articular surfaces of the mesocuneiform
are extremely variable in size and shape.
Ectocuneiform.—A raised, rugose knob is
present on the anterior surface of the ectocuneiform
(Figs. 64, 71). There is a concavity just posterior to
the midpoint on the lateral edge that corresponds
to the concavity on the lateral edge of the navicu-
lar. Proximally, there is one articular surface for the
navicular that covers nearly the entire surface and
has both the posterior and medial corners turned
proximally. On the posterior portion of the proxi-
mal surface, an edge is formed with the slender,
elongate, lateral articular surface for the cuboid.
There is a small, semi-circular articular surface on
the posteromedial edge for articulation with the
mesocuneiform. This articular surface folds distally
into a rectangular articular surface for articulation
with the second metatarsal. The articular surface
for the second metatarsal forms a lateral edge with
the distal, triangular articular surface for the third
metatarsal. On the lateral edge, this distal articular
surface forms an anterolateral edge with a second,
round articular surface for the cuboid. On the ecto-
cuneiforms of ETMNH 601, the more anterior of
the two cuboid articulations is also in contact with
the proximal navicular articular surface.
Second Metatarsal.—There is a small rugose
prominence on the anterolateral side of the distal
end and a second rugose knob on the posterior sur-
face (Fig. 72). Three articular surfaces are pres-
ent on the proximal end of the second metatarsal.
Medially, there is a round articular surface for the
mesocuneiform. This facet forms a medial edge
with a posteriorly rounded, rectangular proximo-
lateral articular surface for the ectocuneiform. On
the lateral side of the proximal end, the ectocunei-
Figure 69. Right entocuneiform of ETMNH
609. Views: A, anterolateral; B, posteromedial.
Abbreviations: ASM, articular surface for
mesocuneiform; ASN, articular surface for
navicular. Scale bar = 1 cm.
Figure 70. Right mesocuneiform of ETMNH
609. Views: A, anterior; B, posterior; C, proximal;
D, distal; E, medial; F, lateral. Abbreviations:
ASEC, articular surface for ectocuneiform; ASEN,
articular surface for entocuneiform; ASMT2,
articular surface for second metatarsal; ASN,
articular surface for navicular. Scale bar = 1 cm.
248 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
form facet forms an edge with a small, triangular
articular surface for the third metatarsal. Distally,
the anterior articular surface for the proximal pha-
lanx is smooth and angled distomedially from the
anterolateral prominence. On the posterior surface,
the distal articular surface is divided into two fac-
ets by the intermediate relief, which is aligned with
medial rugose bone along the posterior surface.
The facets slant proximomedially and each articu-
lates with a sesamoid.
Third Metatarsal.—The proximal end is posi-
tioned slightly posterior to the distal creating the
slant seen in the articulated pes (Fig. 73). Nutrient
foramina are near the anterior and posterior mid-
points on the third metatarsals. On the proximo-
medial surface, a slender articular surface extends
anteroposteriorly for the second metatarsal. The
proximal edge of this surface contacts the larger,
rectangular proximolateral articular surface for
the ectocuneiform. A raised ridge occurs between
the proximolateral articular surface and the nar-
row, proximomedial articular facet for the cuboid.
On the lateral side of the proximal end, there is
Figure 71. Right ectocuneiform of ETMNH 609.
Views: A, anterior; B, posteromedial; C, proximal;
D, distal; E, medial; F, lateral. Abbreviations:
ASC1–2, articular surfaces for cuboid 1–2; ASM,
articular surface for mesocuneiform; ASMT2,
articular surface for second metatarsal; ASMT3,
articular surface for third metatarsal; ASN, articular
surface for navicular. Scale bar = 5 cm.
Figure 72. Right second metatarsal of ETMNH 609. Views: A, anterior; B, posterior; C, medial; D,
lateral; E, proximal; F; distal. Abbreviations: ALP, anterolateral process; ASEC, articular surface for
ectocuneiform; ASM, articular surface for mesocuneiform; ASMT3, articular surface for third metatarsal;
ASPP2, articular surface for proximal phalanx of second digit; ASS1–2, articular surfaces for sesamoids
1–2; IMR, intermediate relief. Scale bar = 5 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 249
an articular surface for the fourth metatarsal that
has two rounded portions—anterior and posterior.
A straight proximal edge contacts the lateral edge
of the proximal cuboid articular facet. At the distal
end of the third metatarsal, paired, round rugosi-
ties are on the anterior surface and extend distally
around their respective edges forming rugosities
on either side. There is no distinct ridge along the
midline of the posterior side of the diaphysis as on
metapodials of other species, but there is a slight
pair of depressions proximal to the distal facets.
The anterior articular surface for the proximal pha-
lanx is smooth and domed proximally with edges
that are variable in shape. Posteriorly, an inter-
mediate relief that is slanted slightly laterally as
it extends proximally separates the distal articular
surface into two facets that each articulate with one
sesamoid.
Fourth Metatarsal.—The lateral edges of
the fourth metatarsals appear pinched anteropos-
teriorly (Fig. 74), and ETMNH 609 has a slight
inward curvature that is more pronounced than that
of ETMNH 601. On the posterior surface, there is
a rugose bump at the proximal end along the mid-
line of the diaphysis. Only two articular surfaces
are on the proximal end of the fourth metatarsal.
A slightly depressed triangular facet covers the
proximal surface for articulation with the cuboid.
The straight medial edge of this facet forms an
edge with the medial articular surface for the third
metatarsal. This facet consists of two rounded por-
tions—anterior and posterior. The posterior portion
forms a process that extends posteriorly, and the
anterior articular surface, which articulates with
the proximal phalanx, is smooth and domed proxi-
mally with a slant from proximomedial to disto-
lateral. An intermediate relief divides the posterior
articular surface of the distal end into two facets
that each articulate with one sesamoid.
PhAlAnges AnD sesAmoiDs
Because the phalanges and sesamoids of the
Figure 73. Right third metatarsal of ETMNH 609. Views: A, anterior; B, posterior; C, medial; D, lateral;
E, proximal; F, distal. Abbreviations: ASC, articular surface for cuboid; ASEC, articular surface for
ectocuneiform; ASMT2, articular surface for second metatarsal; ASMT4, articular surface for fourth
metatarsal; ASPP3, articular surface for proximal phalanx of the third digit; ASS1–2, articular surfaces for
sesamoids 1–2; IR, intermediate relief; NF, nutrient foramen. Scale bar = 5 cm.
250 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
manus and pes are so similar (Fig. 58), they will
be described together. Phalanges and sesamoids of
the second and fourth digits are larger in the manus
than in the pes. In the third digits, the phalanges
and sesamoids of the manus are approximately the
same sizes as those in the pes. Typical of Teleoc-
eras, the phalanges are compressed so the second
and fourth digits are longer than the third to sup-
port the digitigrade splay of the manus and pes. In
the manus and pes, the third digit is the most com-
pressed. It is important to note that, on the second
digit of the left pes of ETMNH 601, the phalanges
are pathological so that the distal and medial pha-
langes are completely fused and the proximal pha-
lanx is remodeled (Fig. 75).
Proximal Phalanges.—Phalanges of the sec-
ond and fourth digits are nearly mirror images of
each other and are blocky with heavy rugosities
on the non-articular surfaces (Fig. 76). Distally,
these phalanges slope anteriorly so that the pos-
terior edge is positioned superior to the anterior
edge. Shapes of the articular surfaces are variable
within and between individuals; proximal articular
surfaces vary between round and square whereas
distal articular surfaces are more ovate with a small
concavity in the center and a notch on the poste-
rior edge. Proximal phalanges of the third digits
are more compressed anteroposteriorly but wider
mediolaterally.
Medial Phalanges.—Medial phalanges are
much more compressed than the proximal pha-
langes and have rugosities present on every non-
articular surface (Fig. 77). However, like with the
proximal phalanges, the medial phalanges of the
second and fourth digits are nearly mirror images
of each other. In anterior view, these phalanges are
domed proximally. Like with the proximal phalan-
ges, the shapes of the articular surfaces are variable
within and between individuals; proximal articular
surfaces are more ovate whereas the distal articular
surfaces are convex anterior to posterior and just
barely curve over the anterior edges. Medial pha-
langes of the third digits are more compressed than
those of the second and fourth digits.
Distal Phalanges.—All of the distal phalan-
ges are rugose and porous to allow blood vessels
Figure 74. Right fourth metatarsal of ETMNH 609. Views: A, anterior; B, posterior; C, medial; D, lateral;
E, proximal; F, distal. Abbreviations: ASC, articular surface for cuboid; ASMT3, articular surface for third
metatarsal; ASPP4, articular surface for proximal phalanx of digit four; ASS1–2, articular surfaces for
sesamoids 1–2; IR, intermediate relief. Scale bar = 5 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 251
Figure 75. Pathological phalanges of the left hind second digit of ETMNH 601 with healthy phalanges of
the right hind second digit. Notice that the left medial and distal phalanges are fused together. Abbreviations:
DP, distal phalanx; MP, medial phalanx; PP, proximal phalanx; MT2, second metatarsal. Scale bar = 10
cm.
252 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
to reach the hoof structure (Fig. 78; Engiles et al.,
2015). Distal phalanges of the second and fourth
digits arc medially and laterally, respectively, and
narrow to a point giving them a triangular appear-
ance. Shapes of the proximal articular surfaces are
variable within and between individuals, but tend
to be round to ovate and slightly raised along the
anterior edge.
Sesamoids.—All of the sesamoids are rugose
bones with concave articular surfaces for articula-
tion with the metapodials (Fig. 79).
DISCUSSION
The occurrence of Teleoceras aepysoma in the
Appalachian Mountains is unique within a genus
typically found in the Great Plains (Prothero, 2005).
Figure 76. Proximal phalanges of the right manus of ETMNH 609. Views: A, anterior; B, posterior; C,
proximal; D, distal. Abbreviations: II, second digit; III, third digit; IV, fourth digit. Scale bar = 5 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 253
It is possible this unusual habitat contributed to
the atypical morphology. For example, though the
GFS population has many of the characters previ-
ously described as typical of Teleoceras, it lacks
features that can now no longer be used as syn-
apomorphies for the genus (Table 3). Specically,
Teleoceras aepysoma exhibits, as adults: unfused
nasals without a nasal horn and a less rotund body
with longer, more gracile limbs. Limb elements of
Teleoceras aepysoma are considerably elongated,
which is noteworthy in a genus characterized by
“short, robust limbs” (Prothero, 2005:94). Elon-
gated limb bones during the late Hemphillian are
also in contrast to the trend toward an increased
“shortening and stumpiness” of Teleoceras limbs
postulated by Prothero (2005:207; Fig. 80). These
proportional differences are accompanied by other
skeletal and dental characters that differentiate the
GFS taxon and warrant the designation of a new
species of Teleoceras. There are also unusual char-
acters that are not true apomorphies, such as the
presence of fth metacarpals on ETMNH 601 and
p2s on ETMNH 609 and 21659.
Difculties encountered while trying to clas-
Figure 77. Medial phalanges of the right manus of ETMNH 609. Views: A, anterior; B, posterior; C,
proximal; D, distal. Abbreviations: II, second digit; III, third digit; IV, fourth digit. Scale bar = 5 cm.
254 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
sify Teleoceras aepysoma make it clear that the
genus Teleoceras should be revised. For instance,
Prothero (2005:94) describes the nasal incision as
“retracted to anterior P3” as a Teleoceratini syn-
apomorphy, but this feature appears to be dened
incorrectly because most, if not all, Teleoceras
crania, including those from the GFS, have a nasal
incision that extends posterior to the P3. The pres-
ence of the GFS population illustrates the wide-
degree of genus-level variation and brings atten-
tion to the necessity of reexamining previously
known populations for similarly variable character
states. Because of the small sample size of the GFS
specimens, no robust statistical analyses were per-
formed. These analyses will be possible following
further excavation of the site and recovery of addi-
tional elements.
Although Madden and Dalquest (1990:266)
discussed potentially “the last rhinoceros in North
America” from Blancan sediments in Texas, this
is only a small, isolated tooth fragment identied
as Teleoceras based on size, and it is possible that
Figure 78. Distal phalanges of the right manus of ETMNH 609. Views: A, anterior; B, proximal.
Abbreviations: II, second digit; III, third digit; IV, fourth digit. Scale bar = 5 cm.
Figure 79. Posterior view of sesamoids articulated
with the fourth metacarpal. Scale bar = 5 cm.
SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 255
it may have been reworked (Prothero, 2005). Gus-
tafson (2012) made similar claims about an early
Blancan Teleoceras tooth from Washington with
similar reworking potential. Until more material
is found, these specimens do not justify extending
the temporal range of Teleoceras beyond the end
of the Hemphillian. Therefore, the Gray Fossil Site
can be added to the latest Hemphillian localities
that contain the last of the North American rhinos:
the Mount Eden Fauna of California, USA; the
Yepómera (Rincon) Fauna of Chihuahua, Mexico;
the Rancho El Ocote Fauna of Guanajuato, Mex-
ico; and the Palmetto Fauna of Florida, USA (Ted-
ford et al., 2004; Webb et al., 2008).
ACKNOWLEDGEMENTS
The authors would like to thank the numerous
museum staff, students, and volunteers who were
involved in this work from the discovery of the fos-
sils to the publication of this manuscript. We thank
J. Mead and B. Schubert for their comments on a
previous version of this manuscript. A. Joyner pro-
vided an initial map, and B. Compton, S. Haugrud,
and A. Nye provided research assistance at the
Gray Fossil Site. Additionally, we are especially
grateful for the access provided to museum collec-
tions by J. Galkin (AMNH), R. Hulbert (FLMNH),
C. Ito (NMNH), L. Ivy (DMNS), and L. Wilson
(FHSM). Finally, the authors thank K. Jansky, L.
Burns, S. Cox, and J. Martin for their support of
this research. This research was supported by a
National Science Foundation grant to S. Wallace
and B. Schubert (EAR-0958985), the ETSU Ofce
of Research and Sponsored Programs, the ETSU
Department of Geosciences, and the Don Sun-
dquist Center of Excellence in Paleontology.
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SHORT ET AL.: A new late Hemphillian rhinoceros from Tennessee 259
Appendix 1. Measurements used for scatterplots (mm). Teleoceras aepysoma data are results of this
research. All other data are from Prothero (2005: tables 4.9, 4.10, 4.11, 5.7, 5.8, 5.9).
T. americanum
T. medicornutum
T. meridianum
T. major
T. brachyrhinum
T. fossiger
T. proterum
T. hicksi
T. guymonense
T. aepysoma
Skull
P2 to occiput 444 482 -- 471 428 -- 475 511 -- 519.76
lambdoid crest to nasals 435 488 -- 483 403 -- -- 490 -- 455.49
width at zygoma 320 350 323 333 353 355 -- 356 -- 357.18
width of occiput 163 200 170 209 200 207 184 226 -- 235.61
height of occiput 161 239 -- 203 180 217 210 198 -- 196.54
Dentition
P2–M3 227 236 -- 243 256 305 328 254 -- 265.99
P2–P4 97 94 -- 99 109 129 104 100 -- 116.29
M1–M3 136 140 138 143 149 178 150 152 159 158.85
p3–m3 210 242 -- 220 243 250 242 241 -- 246.84
p3–p4 72 72 -- 71 83 79 82 72 -- 82.33
m1–m3 141 155 -- 148 165 173 159 172 140 165.74
Humerus
Length -- 333 264 314 311 307 284 315 -- 392.5
Distal Width -- 101 88 97 83 99 91 99 -- 154.1
Midshaft Width -- 56 48 67 54 61 61 65 -- 76.08
Ulna
Length 305 310 -- 293 294 260 262 279 270 389.3
Midshaft Width 29 41 -- 42 31 35 38 42 38 59.20
Radius
Length 257 265 215 257 257 259 252 250 235 310.6
Distal Width 75 86 77 94 73 99 92 95 87 97.9
Midshaft Width 40 48 42 48 41 50 50 53 52 48.84
Metacarpal 3
Length 120 134 104 118 113 115 105 115 117 125.6
Proximal Width 39 51 44 49 42 52 50 51 54 69.8
Femur
Length 340 433 398 384 396 440 392 440 -- 491.6
Distal Width 133 121 110 123 98 113 102 115 -- 134.4
Midshaft Width 51 67 64 69 53 76 61 71 -- 69.99
260 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 56(5)
Appendix 1. Continued.
T. americanum
T. medicornutum
T. meridianum
T. major
T. brachyrhinum
T. fossiger
T. proterum
T. hicksi
T. guymonense
T. aepysoma
Tibia
Length 250 276 218 236 263 236 195 230 220 271.5
Distal Width 70 88 70 85 74 87 75 86 76 90.1
Midshaft Width 45 47 40 49 42 50 47 52 40 51.44
Calcaneum
Length 85 105 -- 125 94 130 124 125 -- 140.2
Width at Sustentaculum 54 63 -- 74 55 78 70 74 -- 77.06
Metatarsal 3
Length 102 110 87 98 99 109 86 84 -- 105.2
Proximal Width 37 48 32 44 37 50 40 39 -- 54.3
... Rhinoceroses in North America are known to have gone extinct in the latest Hemphillian, the last known taxa including Teleoceras hicksi Cook, 1927, from Florida's Palmetto Fauna; the dwarf species T. guymonense Prothero, 2005, known only from Oklahoma, Texas, Kansas, and New Mexico; and T. aepysoma Short et al., 2019, from the Gray Fossil Site of eastern Tennessee. The species from SC is much smaller than T. hicksi, T. aepysoma, and the above noted Aphelops malacorhinus, but is similar in size to T. guymonense. ...
... It differs from the latter in having a wear facet on the anterior surface of p3, thus indicating the presence of p2. Although the p2 is typically lost in later species of the genus, Prothero and Manning (1987) noted that the p2 is occasionally retained, and this was recently exemplified by specimens of T. aepysoma described by Short et al. (2019) that ranged from having no p2s, to having vestigial p2s, to specimens that retained the p2s. Aphelops malacorhinus also retains p2, but this species is considerably larger than the Morgan River taxon. ...
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... This site is interpreted as a sinkhole which, over thousands of years, filled into a lake within a dense canopied forest approximately 4.9-4.5 Ma (Shunk et al., 2006(Shunk et al., , 2009Samuels et al., 2018). A wide variety of flora and fauna are known from the site, including mammals, reptiles, and amphibians (Parmalee et al., 2002;Wallace and Wang, 2004;Shunk et al., 2006Shunk et al., , 2009Zobaa et al., 2009Zobaa et al., , 2011Boardman and Schubert, 2011;Ochoa et al., 2012;2016;Jasinski, 2013;Worobiec et al., 2013;Bourque and Schubert, 2015;Crowe, 2017;Samuels et al., 2018;Short et al., 2019). Given the age and occurrences of frost intolerant plants and reptiles at the site, estimates would be expected to be relatively warm and wet in this area, but there are no published estimates for the site to date. ...
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