THEFOSSIIL RECORD OFARCTODUS PRLSTINUS
(URSIDAES TREMARCTINAE) IN FLORIDA

Steven D. Emsliet

ABSTRACT

,€17841 Bnd  posteranial~ :elements of.at least eight individuals of Arcrodus pristinus (Unidae:
TremarctkIBe))913~ ret?9'~51 hom Eeisey Shell' Pit, an early Irvingtonian vertebrate'locality within a marine
shell'bedj.pental m4Fremeritstindicate that two distinct sizes, presumably representing malds and fanales,
are,regqgoizable@ntte collectio~ This bear tentatively is referred,from. 13 localities in Floridii, ranging jin
age fromflate Bjancan to lat, Irvingipman,  and is a biochronological indicat6r for this period. Another
tremf#®e bew, Tremarctosf;oridanus, sofar is knoBn only from Rancholabrean localities initioiidiDand
may,have,ecologically,rsplaced A. pristinus.

RESUMEN

Je reportan eleinentos craneales y post craneales pertenecientes a por lo mqos ocho individuos
de *rodus',prisiinus ,(Wisidae: Tremarctinae)  provenientes del depdsito de conchuelas de Ikisey,  una
Ipcalidad ds Wttebrados del  Irvingtoniano temprano contenido en una capa de conchuelas marinas. Las
mediciones,dental*{inaican la presencia de dos diferentes tamailds, los cualdspresatiblemante ~resentan
a mactios ,y, hemBras  eb la colecdi6n, Este osd' bs t6ntativamente teferido a 13 Ilocalidades en 1Florida,
itba**i,86 eir edad: datia al Balnban6 tatdio hasta ) Irvingtoniano tardio, siendo un indicador
bid¢fohol&~66:de:attipetiodo. Otto oso tremarctino, Tremdrctodoridanus, es conocido hasta ahorats616
pWi lodlidadss f  Banchol abreangen florida, pudiendo haber reemplazado ecoltgicamente a A. pris tinus.

1
Thejauthor.ista<Couitesy.turator. Flolida Mpsum of N,tural·Hi~tory, University  of Fld,ida, P. 0. Box 1 17800, Gunciville FL 32611-

7860,,Ij.5.A.,~nd 633istanl Proffssorin the  Department Scien=, Westem State College, Gunnison CO 81230, U.S.A.

'EMIEf,fs:D. 1995'.. The-Fdssitrecord ofArctodus pristinus (Ursidae: Tremarctinae)'in Florida. Bull.
Flotida{Mus. Nat Hist 37, PLIi(15):501-514.



502 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, PL 4 No. 15

INTRODUCTION

The short-faced bear Arctodus pristinus was described by Leidy (1854, 1859)
based on a single left m2 from the Ashley River beds, South Carolina Since that
time, although the type specimen apparently was lost, additional material has been
reported from Pennsylvania, Maryland, West Virginia, Florida, and Mexico
(Kurt6n 1967; Kurt6n and Anderson 1980; Dalquest and Mooser 1980). All
specimens of known age date to the late Blancan through Irvingtonian.

In 1983, shell mining operators at Leisey Shell Pit, Hillsborough County,
Florida  uncovered a rich deposit of terrestrial vertebrates within the marine shell
beds. The bone layer, designated Leisey Shell Pit 14 was excavated for over a
year by amateur paleontologists and personnel from the Florida Museum of Natural
History (FLMNH), Gainesville. Based on associated invertebrate and vertebrate
faiinas, reversed paleomagnetism and strontium stratigraphy, the deposit is dated to
the late early Irvingtonian (Hulbert and Morgan 1989; Webb et al. 1989).
Vertebrate remains at the site include cranial and postcranial bones of at least five
individuals of Arctodus pristinus. These remains are described here; other
carnivores from Leisey lA are reported by Berta (this volume). One bone of A.
pristinus from Leisey lB, located stratigraphically below Leisey 14 two bones
from Leisey 1 (from either Leisey lA or B), and one bone from Leisey 3, located
0.5 km west of Leisey 14 also are reported. As with Leisey 14 Leisey lB and 3
are located within the Bermont Formation and date to the late early Irvingtonian.

ACKNOWLEDGEMENTS

I thank the following people for their assistance with fossil and Recent skeletal material at museums:

Phil Angle, Larry Barnes, Sam Mcked, Clayton E. Ray, Charles Smart, and Richard Tedford. Gary S.

Morgan provided information on unreported fossil records of Arcrodus in Florida, and Clayton E. Ray

generously provided unpublished information on tremarctine bean Richard Tedford and Ray commented
on an earlier draft of the paper, Morgan and Richard C. Hulbert, Jr., also provided helpful comments and

suggestions. Mary Ellen Ahearn provided the photographs
I also thank the amateur paleontologists of Florida through whose efforts nu,ch of the m**crial from

Leisey Shell Pit was preserved for scientific study. Those deserving particular recognition are Ralph "Tony"
Esteveg Mickey Fowler, Frank A Garcia. and Eric Hunter. Finally, C. E. "Bud" Leisey. Jr., generously

arranged mining operations at Lcisey Shell Pit so that vertebrate fossils could be excavated.



EMSLIE: FOSSIL RECORDARCTODUSPWSTINUS INELORIDA 503

METHODS

Fossil specimens of Arctodus pristinus, A. simus, and Tremarctos flondanus were examined at the
Florida Museum of Nabiral Hid-y (UF); the National Museum of Natural History (USNM), Smithsonian
Institution, Washington, D. C.; the American Museum of Natural History (AMNA FAM), New York; the
Academy of Natural Sciences (ANSP). Philadelphia; the Natural History Museum of Los Angeles County
(LACM); and the University of California Museum of Paleontology (UCMP), Berkeley. Skeletons of T.
ornatus also were examined at USNM and AMNH. All ' were taken with vernier and
anthropometric calipern Dental measurements used in this study are self-descriptive; length and width were
taken at the base ofthe enamel ofeach tooth. Trigonid length of the ml was taken from the posterior edge of
the extracusp atthe lateral border of the trigonid andtalonid to the anterior base ofthe paraconid

SYSTEMATIC PALEONTOLOGY

Order CARN[VORA Bowdich 1821
Family URSIDAE Gray 1825
Subfamily TREMARCTINAE

Arctodus I.eidy 1854
Arctodus pristinus lkidy 1854

Referred Material.- Leisey 1: left femur lacking proximal end, UF
129077; left tibia lacking proximal end, UF 129078; left mandible with cl, p2-3,
ml (partial), and m2, Royal Ontario Museum (ROM) 31462. Ikisey lA: left I3,
UF 81697; right premaxilla with I2, UF 81695; left premaxilla with Il-2, UF
81696; right P4, UF 81739; left P4, UF 81740; two right Ml's, UF 81698-81699;
right M2, UF 67089; left M2, UF 81741; right i3, UF 87298; right mandible with
cl, p4-m2, UF 81693; right mandible with p4-m3, UF 64300; left mandible with
cl, p4-m2, UF 81692; left nundible with cl, ml-m3, and right mandible with ml-
m3 UF 81694; right metacarpal III, UF 116092. Leisey 18: left humerus lacking
proximal end, UF 95882. Leisey 3: distal left radius, UF 129079; left metacarpal
II, UF 142232. Collectively these specimens represent a minimum of eight
individuals.

Description.- Dental and mandibular measurements of this material are
provided in Tables 1-2. These specimens display the typical features of
Tremarctinae: the presence of an extra lateral cusp on the m 1 between the trigonid
and talonid, a premasseteric fossa on the mandible (Kurt6n and Anderson 1980),
and an entepicondytar foramen on the humerus. Characters that most readily
distinguish Arctodus pristinus from A. simus include generally smaller size,
relatively narrower cheek teeth, and less crowded anterior lower premolars.
Although there is considerable variation in body size in these bears, it is possible to
distinguish the two species by measurements and proportions of the teeth (Kurt6n
1967).



504 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, PLII, No. 15

Many characters of the teeth in Arctodus pristinus are identical to A. simus, as
described by Merriam and Stock (1925). The fossil species " Ursus (Arctodus)
haplodon," described by Cope (1896) based on material from Port Kennedy Cave,
Pennsylvania, now is referred to A. pristinus (Kurt6n 1967). Cope based his
description solely on the m2, however, and did not describe this material in detail.
Gidley and Gazin (1938) later referred these specimens to Arctodus "haplodon,"
again limiting their comparisons primarily to the m2. Although Kurt6n (1967)
completed a thorough quantitative analysis of the dentition of Arctodus, including
A. pristinus from Port Kennedy Cave, the teeth of this species have yet to be
described. Description of the dentition of A. pristinus from Leisey lA is presented
here. A more detailed comparison and description of this bear from all fossil
localities in Florida is beyond the scope of this paper.

The I 1-2 (UF 81695-81696) of A rctodus pristinus are nearly equal in size and
the I3 (UF 81697) is significantly larger. The first two upper incisors are not
shovel-shaped, as are the lower incisors, and form a triangular occlusal surface
with the anterior edge only slightly higher-crowned than the posterior edge. A
shallow groove extends from the base to the crown on the anterior surface, slightly
lateral to the midline. The root of I3 is approximately 25% longer than the roots of
the frst two incisors, and the crown curves laterally. Small wear facets occur near
the base of the enamel on the medial SUfface, where it contacts I2, and on the

lateral surface where it is met by cl during occlusion.
The P4 (UF 81739, 81740) has a shearing surface formed on the medial face

of the protocone and metacone. The paracone is small, its unworn crown not
extending higher than the trench dividing the paracone and metacone. This tooth
has three roots, but those below the metacone and protocone are fused.

The Ml (UF 81698-81699; Fig. lA and B) has four distinct cusps forming
the internal border in the unworn state. With moderate wear, the posterior two of
these cusps form a single ridge. The occlusal surface between the equally
prominent paracone and metacone and the internal border is crenulated and has a
row of three distinct tubercles. The middle tubercle is the largest; the anterior and
posterior tubercles connect to the paracone and metacone respectively by small
ridges. The antero-internal corner of the tooth has a distinct cingulum giving this
area a square shape. Small wear facets occur on the anterior side below the
paracone, where it contacts the P4, and on the posterior side where it contacts the
M2.

The M2 (UF 81741, 67089; Fig. iC and D) has a prominent paracone and
slightly less prominent metacone. The breadth at the metacone can be equal to or
slightly less than the breadth at the paracone. Posterior to the metacone, the tooth
tapers significantly. The occlusal surface is greatly crenulated and a small
cingulum occurs on the antero-internal corner of the tooth. A small wear facet is
present on the anterior side where it abuts the Ml. This tooth was found to be
highly variable in modern Tremarctos omatus. In the Leisey specimens, variations
are apparent as well: UF 81741 has a relatively longer "heer and the tooth tapers
more abruptly than in UF 67089.



EMSLIE: FOSSIL RECORD ARCTODUS PRISTWUS IN FLORIDA 505

CD

Figure 1. Upper cheek teeth of Arctodus pristinus from Leisey Shell Pit lA showing specimens probably
from males (left) and females (right). (A) UF 81698, RMU (B) UF 81699, RMl; (C) UF 81741, LM2; (D)
UF 67089, RM2. Scale 14 Bar=2 cm.

The i3 (UF 87298) is distinctly shovel-shaped and has a prominent lateral
flange. The canine (UF 81692-816933; Fig. 2) is heavily rooted and broadest at
the base of the enamel. A distinct ridge extends from the apex of the crown to the
base on the antero-internal border, and a shorter and less distinct ridge is found at
the postero-internal border.

The p4 (UF 64300, 81692-81693; Figs. 2-3) is robust, with a single
prominent cusp. In the unworn condition, this cusp is much lower than the apex of
the unworn paraconid of ml. The posterior side contacts the base of the ml. This
tooth has two fused roots.

The ml (UF 64300, 81692-81694; Figs. 2-3) has a high paraconid and
protoconid that form a weak, lateral shearing surface. With moderate wear, the
shearing surface is lost and the paraconid and protoconid wear flat. The trigonid is
divided from the talonid by a prominent metaconid medially, and a small extra
cusp laterally that is lost with moderate wear. The talonid is expanded laterally
forming a large crushing platform with the trigonid of m2.



506 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, PL II, No. 15

A

C

Figure 2. Left mandible, UF 81692, in occlusal (A) and lateral views (B) and left mandible, UF 81694, in

occlusal (C) and lateral views (D) ofArctoduspnstinus from Izisey Shell Pit lk Scale at top .44X bar=5

cm; bottom.75X bar2 cm.



EMSLIE: FOSSIL RECORDARCTODUSPR/STINUS IN FLORIDA 507

A

C

D

Figure 3. Right mandible, UF 81693, in occlusal (A) and lateral (B) views and right mandible, UF 64300 m
occlusal (C) and lateral (D) views ofArcrodus pristinus from Lciscy Shell Pit lA Scale at top .62X, bar=3
cm; bottom.94 bar=2 cm



508 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, PL 4 No. 15

Table 1. Dental measurements (mm) ofArctoduspristinus from Lkisey Shell Pit lA

Greatest Anterior Central
Specimen Lmgth width width width

P4 UF 81739 17.5 13.2
UF 81740 20.3 16.0

MI UF 81698 25.1 21.8
UF 81699 20.6 17.7

142 UF 67089 33.0 19.6 17.7
UF 81741 39.0 22.5 20.7

The m2 (UF 64300, 81692-81694; Figs. 2-3) is usually broader anteriorly but
the shape of this tooth is variable, and it can be equally broad or broader
posteriorly (see also Cope 1896 and Kurt6n 1967). The most prominent cusp is the
metaconid which is connected transversely with the protoconid by a distinct,
trenchant ridge. This ridge divides the short, basin-shaped trigonid from the long
talonid. Two oblique tubercles occur in the talonid and are lost with moderate
weari the anterior tubercle is connected to the lingual border of the crown by a
small ridge.

The m3 (UF 64300, 81694; Figs. 2-3) also varies in shape but is usually
broadest anteriorly and tapers posteriorly giving the tooth an oval shape. The
protoconid is the most prominent cusp, and the occlusal surface is crenulated.

The nearly complete mandible (UF 81692; Fig. 2A and B), has alveoli for il-
3 that are considerably crowded so that i2 has been pushed posterior to il and i3.
The anterior premolars, however, are well-spaced with the greatest diastema
occurring between p2 and p3. The premasseteric fossa is moderately developed.
The condyloid process, viewed laterally, is located high above the occlusal surfaces
of the cheek teeth, and a prominent and robust angular process extends only
slightly posterior to the posterior border of the condyloid process. A large mental
foramen occurs at the midline of the ramus, below the anterior root of p4. The
cheek teeth are fully erupted and have light wear.

The paired mandibles, UF 81694 (Fig. 2C and D), are from the largest
individual represented in the sample. The cheek teeth have light to moderate wear,
and the premasseteric fossa is weakly developed. This fossa seems to form with
age; it was observed to be poorly developed in subadults of the living spectacled
bear, Tremarctos ornatus, but completely developed in adults. The con*loid
process, viewed laterally, is only slightly higher than the occlitgal surfaces of the
cheek teeth, and the angular process is missing.

The right mandible (UF 81693, Fig. 3A and B) and left mandible (ROM
31462) are from young individuals The cheek teeth are fully erupted with light



EMSLIE: FOSSIL RECORDARCTODUSPRISTINUS INFLORIDA 509

Table 2. 1 = "* * ( 1 ~ Lciscy Shell Pit lA Depth at
diastema is taken between p2 and p3.

I.~ngth Depth at Ant Post Trig
Speciinen ct-013 diasteina Length Width Width Width L=gth

UF 81693 123.3 43.6

p4 10.7 6.8
mt 24.8 10.5 13.0 16.5
m2 23.5 15.2 13.1

UF 64300

p# 11.3 6.8
ml 23.0 10.6 13.1 16.0
m2 22.6 15.5 15.0
m3 16.1 13.5

UF 81692 149.5 48.8 241.0

cl 17.5
p4 11.1 7.3
ml 27.0 11.4 14.3 18.0
m2 26.5 17.5 17.7

UF 81694

cl 17.3
ml 29.5 13.2 16.0 20.5
n12 28.0 18.7 19.0
n13 21.3 16.4

wear, and the premasseteric fossae are weakly developed. The canines are unworn,
and the root is incompletely ossified and fragmented in UF 81693. The coronoid
and angular processes are missing in both specimens.

The right mandible (UF 64300, Fig. 3C and D) is from a small adult, and the
cheek teeth have moderate wear. The premasseteric fossa is mostly missing but
appears to be weakly developed.

Quantitatively, the teeth of Arctodus pristinus from Leisey lA fall into two
size classes presumably representing males and females (see Fig. 1 and Tables 1-
2). Unfortunately, the sample size from Leisey lA is too small to be meaningful,
or to illustrate graphically. UF 81698, 81740-81741, 81692, and 81694 are from
large individuals or males; UF 81699, 67089, 81739 and 64300 are from small



510 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, PL n, No. 15

individuals or females. All measurements fall within the size range, or smaller,
than measurements ofA. pristinus given by Kuan (1967).

DISCUSSION

Arctodus pristinus is now known from 13 localities in Florida (Fig. 4).
Because material from most of these localities has not been reported or described,
identification remains tentative. The material ranges in age from late Blancan and
early Irvingtonian (Sante Fe River 1, Webb 1974; Kissimmee River, Morgan and
Hulbert this volume; Inglis 14 Klein 1971; Speaker Carr 1981) to latest
Irvingtonian (Coleman 2A; Ritchie 1980). The species is incorrectly reported from
the Waccasassa River (Rancholabrean) by Webb (1974) and Kurt6n and Anderson
(1980); the material is actually Tremarctosforidanus. These records indicate that
A. pristinus is restricted to late Pliocene to middle Pleistocene localities in Florida
and is a biochronological indicator for the late Blancan through Irvingtonian.

A single left M2 (UF 10700) from Sante Fe River 1, Gilchrist County, and a
left I3 (UF 51248) from Kissimmee River, Okeechobee County, are so far the
earliest records of Arctodus from Florida These localities all date to the late
Blancan (Morgan and Hulbert this volume). UF 10700 is similar in most features
to UF 67089 and 81741 from Leisey 14 and given the amount of morphologic
variation that is apparent in this tooth (see above), it probably represents A.
pristinus. UF 51248 is nearly identical to a left I3 (UF 81697) from Leisey lA.

A nearly complete left mandible with cl and ml-3 (cast of specimen, UF
40089) from Rigby Shell Pit  Sarasota County, is very similar to UF 81692 in size,
and in spacing of alveoli for anterior premolars and incisors. A partial right Ml
(UF 124534), a right i3 (UF 60852), and fragmentary shafts of an ulna (UF 40092)
and a radius (UF 40093) also are known from this site. A partial palate with left
I2, right and left Cl, and right and left P4-M2 (UF 136072) was collected at Bass
Point Waterway in North Port  Sarasota County. This specimen compares well
with UF 81739, 81699, and 67089 but is slightly larger in size. A fragmentary
right premaxilla (UF 19403) from Port Charlotte, Charlotte County, also is from a
large individual. A proximal left metatarsal V (UF 17331) is known from Crystal
River Power Plant  Citrus County. Material from McLeod Limerock Mine, Levy
County, includes a right maxilla with P+M2 (FAM 117477), a right m2 (FAM
117478), a left M2, a left m3, 5 incisors, and a fragment of a canine (FAM uncat.),
all of which compare well with the material from Leisey lA. Only a single right
ml (UF 124536) is known from Apollo Beach, Hillsborough County, and it is
similar in size and characters to UF 81692 from Leisey lA.

Florida records reported by Kurt6n and Anderson (1980) include Coleman
24 Sumter County, and Sebastian Canal, Brevard County. Only a single isolated
tooth is known from each of these localities: a left Ml (UF 12363) from the



EMSLIE: FOSSIL RECORDARCTODUSPR/STINUSIN FLORIDA 511

2

5 64<

0 3
1

0

6.

..0 0.

Figure 4. Vertebrate localities in Florida from which remains of Arctodus pristinus have been identified.
(1) Sante Fe River 1, Gilchrist County; (2) Haile 164 Alachua County, (3) McLeod Limerock Mine, Levy
County; (4) Inglis 14 Citrus County, (3) Cr)*al River, Citrus County, (6) Coleman 24 Sumter County;
(7) Apollo Beach, Hillsborough County; (8) Leiscy Shell Pit, Hillsborough County, (9) Rigby Shell Pit,
Sarasota County, (10) Bass Point Waterway, Sarasota County, (11) Pod Charlotte, Charlotte County, (12)
Sebastian Canal, Brevard County, (13) Kissimmee River, Okeechobee County.

former, and a right m2 (UF 19402) from the latter. These specimens are nearly
identical in size and characters to UF 81698 and 81694, respectively, from Leisey
lA and consequently may represent male individuals. Other material from Florida
is more extensive and includes 17 cranial and 106 postcranial elements ofat least 5
individuals from Haile 164 Alachua County, and 4 cranial and 21 postcranial



312 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, Pt. 4 No. 15

bones of at least 2 individuals from Inglis 14 Citrus County. The specimens from
Inglis include a braincase and auditory region of the skull previously unknown for
Arctodus pristinus.

By far the largest sample of dentition of Arctodus pristinus is from Port
Kennedy Cave, Pennsylvania  which Cope (1896) estimated to represent at least 36
individuals. Kurt6n (1967) completed a quantitative analysis of this material in
comparison to A. simus and found that these species could be distinguished by
measurements and proportions of the teeth, despite a large variation in body size.
An examination of the Port Kennedy material indicated no major differences with
that from Leisey lA.

A crushed right mandible (USNM 8005) of Arctodus pristinus from
Cumberland Cave, Maryland  lacks all teeth except a fragmentary i3, canine, and
fragmentary m2. The alveoli of il-2, with i3, are spaced similarly to those of UF
81692. Morphological features of the canine and m2 are identical to the Leisey
material. A left maxilla with Ml-2, formerly ai Princeton (PU 18794) and now at
Yale, was not examined. A complete right and left tibia (USNM 8180), apparently
from one individual, also are known from this cave.

A right mandible of Arctodus pristinus from Aguascalientes, Mexico, was not
available for comparison but is discussed by Dalquest and Mooser (1980). This
specimen has all teeth except the pl-3 and p4; dental measurements provided by
these authors are compatible with Kurt6n's (1967) measurements for this species.
The mental foramen is positioned slightly more rostral than in UF 81692, and the
largest diastema is between p3 and p4 instead of p2 and p3. The depth of the
ramus at this latter diastema is greater in the Mexican specimen (57 mm) than in
UF 81692-81693 (Table 2). A crushed skull and jaws (FAM 98969) and
fragmentary skeletal elements from the Irvingtonian locality at Stout's Ranch,
Seward County, Kansas, may represent a large A. pristinus (R. Tedford pers.
comm.). The specimen is similar in size to small individuals of A. simus, and has
a relatively longer ml (30.0 mm) compared to,4. pristinus from Leisey 14 but the
lower premolars are well-spaced. If it does represent A. pristinus, it extends the
geographic range of this species into the midwestern U. S.

CONCLUSIONS

Arctodus pristinus is now known from 13 late Pliocene and early Pleistocene
localities in Florida. The sample from Leisey Shell Pit adds to the growing list of
records, and to our understanding of this species. A closely related species,
Tremarctos floridanus, also is well-known from Florida from at least 19 sites (it is
incorrectly reported from Inglis lA and Withlacoochee River 7A by Webb [1974]
and Kurt6n and Anderson [1980]). All known-age specimens date to the late
Pleistocene (Rancholabrean) and do not coincide with the presence of A. pristinus
within the state. It is possible that T. floridanus was an ecological replacement of



EMSLIE: FOSSIL RECORDARC70DUSPRIST/NUSIN FLORIDA 513

A. pristinus. Both species, as well as A. simus from western North America, were
probably largely herbivorous (Kurtdn 1966, 1967; Kurt6n and Anderson 1980;
Emslie and Czaplewski 1985), much like the extant spectacled bear, T. ornatus, in
South America (Peyton 1980). T. jloridanus is known  however, from early
Irvingtonian and Blancan localities in western North America (Kurt6n and
Anderson 1980) and may yet be found in similar-aged sites in Florida

Material of Arctodus pristinus in Florida exhibits not only sexual
dimorphism, but also differences in morphologic features that probably represent
temporal and geographic variation. Considerable sexual variation was observed in
16 skeletons of T. omatus at USNM: males are usually larger and have a large
sagittal crest  whereas females are smaller and have a reduced or no sagittal crest.
In addition, the features of the dentition can be quite variable, particularly the M2.
Study of these variations is needed prior to futther systematic work with fossil
tremarctines.

LITERATURE CITED

Cope, E. D. 1896. New andlittle known Mammatia from the Port Kennedy bone deposit Proc. Acad. Nat
Sci. Philadelphia 48:378-394.

Dalquest. W. W., and O. Mooser. 1980. Arctodus pristinus Lkidy in the Pleistocene of Aguascalientes,
Mexico. J. Mann. 61 (4):724-725.

Emslie, S. D., and N. Czaplewsid 1985. A new record of giant short-faced bear Arctodus simus from
western North America. with a re-evaluation of its paleobiology. Contrib. Sci. Nat. Hist. Mus.
Ins Angeles Co. 371:1-12.

Gidley, J. W., and C. I.Gazin. 1938. The Pleisto©ene vertebrate fauna from Cumberland Cave, Maryland-
U. S. Natl. Mus. Bull. 171:1-99.

Hulbert. R. C., Jr.. and G. S. Morgan. 1989. Stratigraphy. paleoecology, and veltebrate fauna ofthe Leisey
Shell Pit I,ocal Fauna, early Pleistocene (Irvinglonian) of southwestern Florida. Pap. Florida
Paleon. 2.1-19.

Klein, J. 1971. Fossil mammals from Inglis 14 late Blancan of Citrus County, Florida. M. S. Thesis
Univ. Florida. Gainesville.

Ku,14 B. 1966. Pleistocene bears of North America 1. Genus Tremarctos, spectacled bears. Ada
Zoologica Fennica 115:1-120.

1967. Pleistocene bears of North America 2. Genus Arctodus, short-faced bears. Acta
Zoologica Fennica 117:1-60.
, and E. Anderson. 1980. Pleistocene Mammals of North America  Columbia Univ. Press, New
York.

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