Front Cover
 Table of Contents
 Taxonomic history of Smilodon
 Systematic paleontology
 Description of Florida materia...
 Size trends
 Geographic and stratigraphic...
 Literature cited
 Back Cover

Group Title: Bulletin of the Florida State Museum
Title: The sabercat Smilodon gracilis from Florida and a discussion of its relationships (Mammalia, Felidae, Smilodontini)
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00095816/00001
 Material Information
Title: The sabercat Smilodon gracilis from Florida and a discussion of its relationships (Mammalia, Felidae, Smilodontini)
Series Title: Bulletin - Florida State Museum ; volume 31, number 1
Physical Description: 63 p. : ill., map ; 23 cm.
Language: English
Creator: Berta, Annalisa
Florida Museum of Natural History
Publisher: Florida State Museum, University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 1987
Copyright Date: 1987
Subject: Smilodon gracilis   ( lcsh )
Mammals, Fossil   ( lcsh )
Paleontology -- Florida   ( lcsh )
Genre: bibliography   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
Bibliography: Includes bibliographical references (p. 50-53).
General Note: Cover title.
General Note: Abstract in English and Spanish.
Statement of Responsibility: Annalisa Berta.
 Record Information
Bibliographic ID: UF00095816
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 15702264

Table of Contents
    Front Cover
        Page i
        Page ii
        Page 1
        Page 2
    Table of Contents
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
    Taxonomic history of Smilodon
        Page 8
        Page 9
        Page 10
        Page 11
    Systematic paleontology
        Page 12
        Page 13
    Description of Florida material
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
        Page 36
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
        Page 42
    Size trends
        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
    Geographic and stratigraphic distribution
        Page 48
        Page 49
    Literature cited
        Page 50
        Page 51
        Page 52
        Page 53
        Page 54
        Page 55
        Page 56
        Page 57
        Page 58
        Page 59
        Page 60
        Page 61
        Page 62
        Page 63
        Page 64
    Back Cover
        Page 65
Full Text

of the
Biological Sciences
Volume 31 1987 Number 1





ENCES, are published at irregular intervals. Volumes contain about 300 pages and are not
necessarily completed in any one calendar year.

S. DAVID WEBB, Associate Editor
RHODA J. BRYANT, Managing Editor

Consultants for this issue:


Communications concerning purchase or exchange of the publications and all manuscripts
should be addressed to: Managing Editor, Bulletin; Florida State Museum; University of
Florida; Gainesville FL 32611; U.S.A.

This public document was promulgated at an annual cost of $4080.00 or
$4.08 per copy. It makes available to libraries, scholars, and all interested
persons the results of researches in the natural sciences, emphasizing the
circum-Caribbean region.

Publication date: 30 January 1987

Price: $4.10







Dentitions and limbs of the sabercat, Smilodon gracilis (Cope 1880), are
described from several Florida localities, ranging in age from the late Blancan through the
Irvingtonian. These samples provide the largest and best known record of the gracile
sabercat. Specimens of S. gracilis from Florida are similar to the type material from Port
Kennedy Cave, Pennsylvania.
Smilodon gracilis is most closely related to S. populator Lund 1842 (junior
synonyms include S. floridanus Leidy 1889, S. californicus Bovard 1907, and S. fatalis Leidy
1868, as revised by Slaughter 1963) and is recorded from diverse localities that range in age
from the late Irvingtonian through the Rancholabrean in both North and South America.
The gracile sabercat is more primitive than S. populator in having upper canines only
slightly recurved; up4 er canines and cheek teeth with very finely serrated anterior and
posterior margins; P with a well developed protocone; mandible with a large flange, two
mental foramina, and a double-rooted P3; less robust limbs and elongate hindfeet.
Smilodon shares a sister group relationship with Megantereon. S. gracilis is more derived
than Megantereon in having incisors enlarged and procumbent, upper canines elongate and
robust, P ectoparastyle well developed, and mastoid and glenoid processes enlarged.
Smilodon gracilis shows a trend toward size increase through time. Limb
morphology and proportions of smilodontines (including S. gracilis) are similar to forest

* Dr. Berta is an Associate Professor, Department of Biology, San Diego State University,
San Diego CA 92182. This paper was completed during her tenure as a Postdoctoral Fellow
in the Department of Natural Sciences at the Florida State Museum, University of Florida,

BERTA, A. 1987. The sabercat Smilodon gracilis from Florida and a discussion of its
relationships (Mammalia, Felidae, Smilodontini). Bull. Florida State Mus., Biol. Sci.


felids although these sabercats are usually better sampled at sites where plains and open
woodland habitats predominated. Judging from its highly specialized dentition and
powerful, short limbs and feet, Smilodon evolved prey capture techniques that relied upon
stalking and ambush rather than rapid pursuit.


Se described las dentaduras y extremidades del tigre dientes de sable, Smilodon
gracilis, provenientes de variosas localidades en Florida. Las edades varian entire el
Blancano tardio ygel Irvingtoniano. Estas muestras constituyen los registros mas numerosos
y mejor conocidos del tigre dientes de sable. Los especimenes de S. gracilis en Florida son
similares al prototipo de la cueva de Port Kennedy Cave (Pennsylvania).
Smilodon gracilis es un pariente cercano de S. populator Lund 1842 (sin6nimos
recientes incluyen: S. floridanus Leidy 1889, S. californicus Bovard 1907, y S. fatalis Leidy
1868 revisado por Slaughter 1963), el cual ha sido registrado en varias localidades y cuyas
edades varian entire el Irvingtoniano tardio y el Rancholabreano, tanto en Norte como Sur
America. El tigre dientes de sable es mas primitive que S. populator, ya que present los
caninos superiores s6lo ligeramente curvados; los caninos superiores y molares carecen del
margen anterior y posterior poco serrado; el P4 tiene el protocono bien desarrollado; la
mandibula tiene un reborde grande; dos for menes y un P3 de double raiz; extremidades
menos robustas y patas traseras elongadas. Smilodon tambi6n esta relacionado al g6nero
Megantereon. S. racilis es mas avanzado que Megantereon porque tiene incisivos
alargados y procumbentes; caninos superiores alargados y robustos; el ectoparaestilo de P
bien desarrollado; y los process mastoideo y glenoideo alargados.
Smilodon gracilis muestra una tendencia al aumento de tamafio a trav6s del
tiempo. La morfologia de las extremidades y proporciones generals de los smilodontinidos
(incluyendo S. gracilis son semejantes a las de los felinos de bosques, aunque las muestras
de dientes de sable generalmenta provienen de sitios con predominancia de llanuras y
bosques abiertos. De acuerdo a su dentadura altamenta especializada y fuerte, las
extremeidades y patas corta, Smilodon desarroll6 t6cnicas de capture de presad en base al
asalto y emboscada, en vez de persecuci6n ripida.



IN T R O D U CT IO N ............................................................................................................................ 3
ACKNOWLEDGEMENTS................................................................... .......................... 4
A B B R E V IA T IO N S ........................................................................................................................... 5
L O C A L IT IE S ..................................................................................................................................... 5
TAXONOMIC HISTORY OF Smilodon..................................................... 8
SYSTEMATIC PALEONTOLOGY................................................... .......................... 12
H olotyp e........................................................................................................................................... 12
T ype L ocality ........................................................................................ .................................. 12
Revised Distribution and Age.......................................................... ........................... 12
E m ended D iagnosis....................................................................................................................... 12
R referred Specim ens...................................................................................................................... 13
DESCRIPTION OF FLORIDA MATERIAL............................ ............................ 14
D en tuition .......................................................................................................................................... 14
Postcranial Skeleton...................................................................................................................... 20
A D A PTA T IO N S................................................................................... ....................... 39
SIZ E T R E N D S.................................................................................................................................. 43
PHYLOGENETIC RELATIONSHIPS............................................................................... 43
GEOGRAPHIC AND STRATIGRAPHIC DISTRIBUTION.............................................. 48
LITER AT UR E CITED ....................................................................... .............. .............. 40
T A B L E S .............................................................................................................................................. 54


The best known Pleistocene sabercat in North America is the genus
Smilodon which has been regarded as a member of the tribe Smilodontini
together with its close relative Megantereon (Kurt6n 1963). Smilodontine
cats represent the culmination of the sabercat specialization. The upper
canines are greatly elongated, slender, and recurved, and how they were
used to capture and kill prey has been much discussed (e.g. Simpson 1941,
Miller 1969, Emerson and Radinsky 1980). Study of the cranial and
postcranial anatomy of these cats has led to interpretations of their
probable behavior and ecology (Gonyea 1976). Despite the amount of
attention Smilodon has commanded in the literature, relatively little is
known regarding the systematics and evolution of smilodontine cats.
The sabertooth "tiger," Smilodon floridanus, recognized here as a
junior synonym of Smilodon populator, is best known from the late
Pleistocene tar pits at Rancho La Brea, California, where thousands of
individuals are represented (Merriam and Stock 1932). S. populator has
been reported from more than 40 late Irvingtonian and Rancholabrean


localities in Arkansas, California, Florida, Idaho, Louisiana, Mexico,
Nebraska, New Mexico, Oregon, Tennessee, Texas, and Utah and also
ranged into South America (Kurt6n and Anderson 1980).
The gracile sabercat, Smilodon gracilis, is less well known. Dental
and postcranial remains are reported from the type locality at Port Kennedy
Cave, Pennsylvania, and from the following Florida faunas: Santa Fe River
IA (Kurt6n 1965), Inglis IA (Klein 1971, Webb 1974b), Haile XVA
(Robertson 1976), McLeod (this report), Bass Point Waterway No. 1
(Churcher 1984), and El Jobean (Churcher 1984; this report). Since this
paper originally went to press, the largest and most complete sample of
Smilodon gracilis has been recovered from a new locality, Leisey Shell Pit
near Ruskin, Florida. A fragmentary lower jaw from Vallecito Creek,
California, is here provisionally referred to Smilodon cf. S. gracilis.
Smilodon gracilis is considerably smaller than S. populator and more
slenderly built. The sabers are enlarged but lack strongly serrated edges. A
distinct protocone and enlarged ectoparastyle are present on P4. The
mandibular flange is large, and P3 is present and usually double rooted.
The limbs are short and less robust.
This report describes the Florida record of Smilodon gracilis.
Previously undescribed material permits a rediagnosis of this species as well
as an evaluation of the phylogenetic relationships, stratigraphic distribution,
and biogeographic significance of Smilodon in North America.


Richard H. Tedford (American Museum of Natural History) and Gay L. Vostreys
and Charles Smart (Academy of Natural Sciences, Philadelphia) kindly allowed use of
collections and/or facilities. John S. Waldrop (Timberlane Research Organization), Roy H.
Burgess, George Miller, and Ted Downs permitted study of specimens in their collections.
Ted Galusha of the Frick Laboratory provided preliminary identification of the
undescribed Florida material. Specimen illustrations were expertly drawn by Wendy
Zomlefer. Howard Converse prepared specimen casts and radiographs. S. David Webb,
William Akerston, Bruce J. MacFadden, C.S. Churcher, Henry Galiano, Robert Hunt, and
Earl Manning critically reviewed this manuscript.
Financial support from Sigma Xi, the Hays Fund of the American Philosophical
Society, the Department of Natural Sciences, Florida State Museum, and the Graduate
School, University of Florida, is gratefully acknowledged. This report is University of
Florida Contribution to Vertebrate Paleontology Number 210.



The following abbreviations are used for specimens from institutional and private
collections: AMNH, Department of Vertebrate Paleontology, The American Museum of
Natural History, New York; ANSP, The Academy of Natural Sciences, Philadelphia,
Pennsylvania; F:AM, Frick: American Mammals, Department of Vertebrate Paleontology,
The American Museum of Natural History, New York; FDT, Florida Diving Tours, Ocala,
Florida (private collection); TRO, Timberlane Research Organization, Lake Wales, Florida
(private collection); UF, Vertebrate Paleontology Collection, Florida State Museum,
Gainesville, Florida.
Other abbreviations are as follows: AP, greatest anteroposterior diameter; C.V.,
coefficient of variation; e, estimated measurement; N, number of specimens; OR, observed
range; SE, standard error; T, greatest transverse diameter; X, mean.
The dental nomenclature used in this paper and illustrated in Figure 1 follows
Neff (written communication 1981). The postcranial terminology follows Jayne (1898) and
Evans and Christensen (1979). All measurements are in millimeters.


Smilodon gracilis is now known from seven localities in Florida
(Fig. 2). This sabercat had previously been reported from the first four
localities listed below.
SANTA FE RIVER IA.--This river-bottom site in Gilchrist County
was discovered by Ben Waller and has produced a mixed collection of
Blancan and Rancholabrean fossils (see Webb 1974a).
HAILE XVA.--This fissure fill deposit within the Ocala limestone is
located on the property of Parker Brothers Limestone Products near Haile
in Alachua County. The site was discovered by P. Kinsey and collected by J.
Robertson, S. David Webb, and R. R. Allen (see Robertson 1976).
INGLIS IA.--A sandy fissure fill deposit in Citrus County within the
Inglis Member of the Ocala Limestone was exposed during canal dredging
operations conducted by the U.S. Army Corps of Engineers. This site was
discovered and first collected by Jean Klein and Robert Martin (see Klein
1971, Webb 1974a).
BASS POINT WATERWAY NO. 1.--This locality consists of
alternating gravel, silt, and sand forming an in situ collecting site in the side
of a canal bank near the town of Northport, Sarasota County (Churcher
1984). The stratigraphy and fauna of this locality are presently being
studied by paleontologists at the Royal Ontario Museum, Toronto, Canada.


ectoprtyle posterior cingulum
metastyle \ r styl
posterior cusplet
metoco no principal cusp

protocone 'protocone anterior cusplet

M1 PA p3

Bior cinuum posterior cingulum
anterior cingulum
protoconid principal cusp
interior cusplet

S p principal cusp

talonid posterior cusplet

M, P, P3

Q i ? 4 Scm

Figure 1. Right Upper (A) and Lower (B) dentition of Smilodon gracilis with dental
nomenclature used in this study. Upper dentition based on UF 18100 and TRO 1664.
Lower dentition based on UF 18102. Anterior is to the right.


0 50 100 150



Figure 2. Smilodon gracilis localities in Florida.


MCLEOD.--A fissure fill deposit, McLeod Limestone Quarry, Smith
Pit, Pocket A, approximately 3.3 km. north of Williston, Levy County. This
site was discovered and collected by Ted Galusha in 1941.
EL JOBEAN.--Canal spoil dumps near the town of El Jobean,
Charlotte County, locality collected by Roy H. Burgess in 1968.
LEISEY SHELL PIT.--A 4-8 cm thick bone bed sandwiched between
thick marine shell beds near Ruskin, Hillsborough County. This site was
discovered by Frank Garcia and collected by associates of the Tampa Bay
Gem and Mineral Society and field parties from the Florida State Museum
in 1983 and 1984. The stratigraphy and fauna of this locality are currently
being studied by paleontologists at the Florida State Museum. A more
detailed study of Smilodon gracilis from this locality will be provided in a
forthcoming paper (Berta, in prep.).


The genus Smilodon was established by Lund (1842), who
described a single species, S. populator, based on material recovered from
the Lagoa Santa Caves, Brazil (see Paula Couto 1955). Earlier, Lund
(1839) erroneously referred some of this material to Hyaena neogaea.
Because at the time of the original designation Hyaena neogaea was
insufficiently defined and no type material was specified, this species is
recognized as a nomen nudum following Kurt6n and Anderson (1980).
The oldest name for a North American Smilodon is Felis
(Trucifelis) fatalis proposed by Leidy (1868) on the basis of a fragmentary
maxilla with P4 and the alveolus for M from the "asphalt beds" in Hardin
County, Texas. Later, Leidy (1869:366, pl. 28, fig. 10) redescribed and
illustrated the specimen under the name Trucifelis fatalis. Although
Merriam and Stock (1932) and Simpson (1945) recognized Trucifelis as a
valid subgenus, all later workers have referred this species to Smilodon (see
Slaughter 1963). The type of S. fatalis is similar to S. gracilis in its small
size, lack of strong serrations, and presence of a protocone. It differs from
S. gracilis in having a well rounded protocone and a larger ectoparastyle on
the upper carnassial. The type of this species is judged too incomplete to
provide a specific diagnosis.
Leidy (1889:13-16, pl. 3, fig. 1) described a fragmentary skull
lacking teeth from a limestone quarry in Marion County, Florida, as a new
species of Machairodus, "M. floridanuss. Beginning with Bovard (1907) all
later workers have referred this species to Smilodon. Bovard (1907)
proposed the species S. califomicus for the excellent sample from Rancho
La Brea, California. He distinguished this species from S. floridanus by its
shorter muzzle, more posterior position of the posterior nares, and ridges


on the palate (the latter of questionable significance). Merriam and Stock
(1932) rejected Bovard's diagnosis and concluded that the principal
difference between this species and S. floridanus was the orientation of the
mastoid process.
Slaughter's (1963) analysis of Smilodon supported the conclusion
previously developed by Lammers (1959) that S. califomicus Bovard is a
synonym of S. floridanus Leidy. Kurten's (1965) study of Florida Smilodon
led him to synonymize S. floridanus with S. fatalis and to maintain S.
califomicus as distinct. He distinguished S. califomicus on the basis of its
larger size, broader mastoid region, and "presence of an accessory cuspule
on M Webb (1974b), in his evaluation of additional sabercat material
from Florida, demonstrated considerable overlap in the ranges of various
measurements between these species and thus strengthened the case for
synonymy of S. califomicus with S. floridanus. A recent study of North and
South American sabercats proposed synonymy of S. floridanus with S.
populator (Berta 1985). S. populator can be distinguished from S. gracilis on
the basis of the following characters: larger size, broadened muzzle, upper
canines strongly recurved, upper canines and cheek teeth with strongly
serrated anterior and posterior margins, P4 with very reduced or absent
protocone, mandible with reduced flange, single foramen, and P3 usually
Slaughter (1963), in a revision of North American Smilodon,
enlarged the concept of S. fatalis and synonymized the following with it:
Smilodontopsis conardi Brown 1908, Smilodontopsis troglodytes Brown 1908,
Smilodon nebraskensis Matthew 1918, Smilodon cf. S. fatalis Lull 1921, and
Smilodon trinitensis Slaughter 1960. He diagnosed S. fatalis as follows:
"total skull length less than any specimen of S. califomicus; occiput narrow
and triangular, not rounded above; basioccipital lacking well developed
vertical keel; inferior canine much reduced with anteroposterior diameter
less than 54 percent of the same measurement of P4; P4 thin, having a
transverse diameter less than 43 percent of the anteroposterior diameter."
As noted by Slaughter (1963), Smilodon species are extremely
variable. Species synonymized by him under S. fatalis fall within the limits
of size and individual variation seen in S. populator (Berta 1985). Size
criteria are not of primary importance in recognition of Smilodon species.
As Slaughter noted, all S. fatalis are not smaller than S. floridanus.
According to Slaughter, triangular skull occipital regions are characteristic
of North American preWisconsin (including late Irvingtonian and early
Rancholabrean) Smilodon, which he referred to S. fatalis. Examination of
North and South American Smilodon suggests that, while it is generally true
that most specimens displaying a triangular occiput are middle Pleistocene
(Irvingtonian and Ensenadan), several late Pleistocene (Rancholabrean and
Lujanian) specimens were found that exemplified this condition (Berta
1985). It is also possible that the shape of the occiput may reflect sexual


dimorphism, because those specimens that exhibit narrow, triangular
occiputs also possess well developed sagittal crests.
Slaughter's diagram showing the relationship between the lower
canine and P is plotted in Figure 3 with the addition of North and South
American middle and late Pleistocene Smilodon (including S. fatalis sensu
Slaughter 1963, S. floridanus Leidy 1889, S. califomicus Bovard 1907, and S.
populator Lund 1842). While S. fatalis (as revised by Slaughter 1963) does
have generally thinner, shorter lower carnassials and canines, additional
material demonstrates that several North and South American populations
of S. populator have measurements whose ranges overlap it. Also apparent
in Figure 3 is the fact that these measurements discriminate Smilodon
chronologically to the extent that the largest specimens of S. populator are
from late Pleistocene (Rancholabrean and Lujanian) localities. Similarly,
late Pleistocene S. populator possess larger, broader lower carnassials than
do middle Pleistocene (Irvingtonian and Ensenadan) specimens (Fig. 3).
No significant differences other than the larger size of late Pleistocene S.
populator were found. Based on these data I propose including S. fatalis
(as revised by Slaughter 1963) as a junior synonym of S. populator.
In addition to S. populator (junior synonyms include S. floridanus
Leidy 1889, S. califomicus Bovard 1907, and S. fatalis Leidy 1868),a second
sabercat species recognized in North America is S. gracilis. This species was
proposed by Cope (1880:857) on the basis of an upper canine root (ANSP
46) recovered from Port Kennedy Cave, Pennsylvania. Additional cranial
and dental material provided the basis for more complete descriptions of
this species (Cope 1895, 1899). Examination of ANSP collections
demonstrated that several postcranial elements were erroneously referred
by Cope (1889) to this species; ANSP 48 (in part) right calcanei and a left
distal humerus. These specimens are comparable in size and morphology to
the jaguar, Felis onca.
Cope (1895) named a second cat, Uncia mercerii, based on three
premolars. Two of these teeth, a left P3 and a right P4 (ANSP 50), are
referrable to Smilodon, and the third tooth may have later been transferred
by him to "Crocuta" inexpectata (Gay Vostreys, written communication
1979). Among a large number of postcranial elements catalogued under S.
mercerfi as ANSP 51, only a proximal right metatarsal II and a left
metacarpal II are referable to Smilodon.
In a third paper Cope (1899) assigned "U." mercerii to the genus
Smilodon, thus recognizing two sabercats from Port Kennedy Cave. He
distinguished S. mercerii from S. gracilis principally by its smaller size and
double rooted P3. Reevaluation of this material indicates similarity in size
(see Tables 1-3) and morphology and supports the synonymy of "U."
mercerii with S. gracilis, as proposed by Kurt6n and Anderson (1980). In
size and dental and postcranial morphology, S. gracilis from Florida
resembles the type material from Port Kennedy Cave.


0 0





* ** I

. *0

* 0

a *

22 23 24 25 26
AP Diameter P4




27 28 29 30


% *:

**. .
0' 0.0 0

K o'

20 21 22 23 24 25 26 27
AP Diameter P4

28 29

Figure 3. Comparative dental measurements of Smilodon populator (North
American sample; Merriam and Stock 1932 and additional specimens) (0 Rancholabrean),
Smilodon fatalis (Leidy 1868) ( = Rancholabrean,dIrvingtonian), and Smilodon populator
(South American sample; Berta 1985) (0= Lujanian, f= Ensenadan).


U ,



E 13.


c 11.




GENUS Smilodon LUND 1842
Smilodon gracilis COPE 1880

Figures 4-18

Smilodon gracilis Cope 1880:857, 1895:448
Machaerodus gracilis Cope 1899:240, pl. XX, fig. 1
Uncia mercerii Cope 1895:448, 1896:392
Smilodon mercerii Cope 1899:245, pl. XX, fig. 2
Smilodon (Smilodontopsis) gracilis Merriam and Stock 1932:15
Smilodontopsis (Machaerodus) gracilis Brown 1908:190
Smilodontopsis (Machaerodus) mercerii Brown 1908:190
Machaerodus? mercerii Matthew 1918:229
Machaerodus? gracilis Matthew 1918:229
Machaerodus gracilis Matthew 1918:229
Machaerodus gracilis Slaughter 1960:490
Machaerodus mercerii Slaughter 1960:490
Megantereon gracilus Martin 1980:149
Ischyrosmilus gracilis Churcher 1984:1

HOLOTYPE.--ANSP 46, root of upper canine.
TYPE LOCALITY.--Port Kennedy Cave, Montgomery County,
Irvingtonian of Pennsylvania and Florida.
EMENDED DIAGNOSIS.--Differs from Smilodon populator in having
upper canines only slightly recurved; upp r canine teeth with very finely
serrated anterior and posterior margins; P with well developed protocone;
mandible with large flange, two mental foramina, double-rooted P3; less
robust limbs and elongate hindfeet. Differs from Old and New World
species of Megantereon in having incisors enlarged and procumbent; upper

canines elongate and robust; P4 ectoparastyle well developed; and mastoid
and glenoid processes enlarged.
ANSP 44, crushed and distorted facial region of skull lacking right M
(crown of left upper canine broken and mandible missing right C); ANSP
45, right M1 in ramal fragment; ANSP 46, left upper canine; ANSP 47, right
and left P4, left M1, left jaw fragment; ANSP 48, right astragalus, proximal
ends of metacarpals II and III, ungual halanx; ANSP 49, right and left rami
missing I1, and P3; ANSP 50, left P right P4; ANSP 51, proximal end
right metatarsal II, left metacarpal II.
FLORIDA.--HAILE XVA: UF 17496, left astragalus, right distal
tibia; UF 17498, right metacarpal II, left distal metatarsal II. SANTA FE
RIVER IA: FDT 488, right P4. INGLIS IA: UF 18097, right premaxillary
fragment with C and P alveolus; UF 18098, root fragment of upper canine;
UF 12929, UF 12930 upper canine; UF 18100, right maxillary fragment with
C alveolus, p34-M1 alveolus; UF 18101, left dP4; UF 18102, partial right
ramus with C alveolus, P3 4, M1; UF 18103, posterior one-half of right
ramus with P4-M ; UF 20065, right ramus with I, C, P alveoli and P4-M1
14-MI; 3 3 4 1,
UF 18104, fragment of left ramus with P3; UF 12931, left condyle and angle
fragment; UF 18105a, fragmentary left ramus with I, deciduous C alveolus
and permanent I and C in crypt, dP34; UF 18105b fragmentary right ramus
with dP3 alveolus, dP4; UF 18105 left dP4 (2), left and right fragmentary
dP4's; UF 12930, upper canine fragments; UF 12932 fragmentary right
ramus with P alveolus, permanent I and C in crypt; UF 12933 left M;
TRO 1664, right maxillary fragment with P4-M ; TRO 1665, left ramus with
13, C alveolus, P4 M1; UF 69921, axis vertebra; UF 45342, cervical
vertebra III; UF 8106, RO 1670, right humerus; UF 18107, distal one-
third (shaft) of right and left humerus; TRO 1669, left humerus missing
proximal end; UF 18109, proximal right ulnae (2); UF 18108, left radius;
UF 18110, right metacarpal IV (2); UF 12934, left metacarpal II; UF 45409,
left metacarpal III; UF 12938, right metacarpal IV; UF 12935, right
metacarpal V; UF 18112, proximal right femur; UF 18113, UF 12936, UF
12937, UF 23999, UF 24000, TRO 1668, right calcaneum; TRO 1666, right
astragalus; TRO 1667, left astragalus; UF 12939, left metatarsal III; UF
12940, right metatarsal IV. MCLEOD: F:AM 95525, partial left maxillary
with C, P3-4; F:AM 95526, upper canine; F:AM 95522, fragment of right
ramus with P4-M1; F:AM 95527, right P4; F:AM 95523, right humerus
missing proximal end; F:AM 95528, shaft portion of left humerus; F:AM
95524, proximal left ulna; F:AM 69223, proximal left ulna missing olecranon
process; F:AM 69220, left radius; F:AM 108538, left scapholunar; F:AM
69249, right metacarpal IV: F:AM 69219, right radius missing proximal end;
F:AM 95529, distal two-thirds of left tibia; F:AM 108538, right patella;
F:AM 108536, left astragalus; F:AM 95532, F:AM 95533, left calcaneum;
F:AM 105838, right cuboid; F:AM 95521, right navicular; F:AM 69241,


right metatarsal III; F:AM 69243, right metatarsal IV; F:AM 95520,
proximal right metatarsal IV; F:AM 95531, right metatarsal V; F:AM
95530, right metatarsal IV missing proximal end; F:AM 95535a, left
proximal phalanx (forefoot); F:AM 95535b, c, right proximal phalanges
(hindfoot); F:AM 108537a, b, c, d, left median phalanges (forefoot). EL
JOBEAN: UF 12941, cast of partial left ramus with P3 alveolus, P4-M1.


DENTITION.--Upper incisors are not represented in the Florida
sample studied herein. A partial maxilla, F:.P 95525 from McLeod,
preserved the right upper canine as well as P (Fig. 4, Table 1). The
canine is elongate, laterally compressed, and slightly recurved
anteroposteriorly. The saber differs from that of Smilodon populator in
being proportionately smaller, shorter, and less curved. Very fine serrations
are developed along the anterior and posterior tooth margins and are
visible only with the aid of a microscope. The root is only slightly thicker
than the alveolar portion of the tooth.
P is preserved in two maxillary fragments, UF 18100 and F:AM
95525 from Inglis IA and MSLeod. A very short diastema separates this
tooth from the canine. P is elongate, double-rooted, and obliquely
positioned in the maxilla. The prominent principal cusp is flanked by a
small, medially placed, anterior cusplet and a slightly larger posterior
cusplet. A broad cingulum forms the heel of the tooth and contributes to
its posterior breadth (Table 1). P is comparable in size and morphology to
Megantereon cultridens, although late Villafranchian representatives of this
species show a trend toward size reduction (see Size Trends).
UF 18100, TRO 1665, and F:AM 95525 all preserve P4 (Figs. 1, 4,
Table 1). This tooth exhibits a well developed sharply pointed protocone
and a separate protoconal root, a character S. gracilis shares with
Megantereon. The protocone is anterolingually positioned at a 500 angle
relative to the anteroposterior axis of the tooth. The parastyle is large and
well developed. A small ectoparastyle is always present. Megantereon
typically shows weaker development of the ectoparastyle. S. populator
shows considerable variation in development of the parastyle and
ectoparastyle. One specimen from the La Brea sample that lacks the
ectoparastyle shows development of a proportionately larger parastyle
(Merriam and Stock 1932:48). The metacone forms the long portion of the
carnassial blade and is low crowned relative to the paracone. The shearing
surface of this tooth is very worn in F:AM 95525, exposing the pulp cavity.
Other specimens display prominent circular wear pits and planar wear facets
on the lingual surface of the tooth between the protocone and parastyle.


0 1 2 3 4 5cm
I Il

Figure 4. Smilodon gracilis, F:AM 95525 from McLeod, Florida. Lateral view of left
maxillary with C, P-


M1 is preserved in TRO 1664 (Fig. 1, Table 1). The tooth is triangular,
transversely elongate, and single rooted most of its length, dividing near the
apex of the root. An elongate labial cusp, the parametacone, is developed,
as well as a lingual protocone. A large wear facet is present between the
parametacone and smaller facets are developed on the anterior and
posterior sides of the talon and on the protocone.
Three right rami; UF 20065, UF 18102, and UF 18103; and one left
ramus, TRO 1665, are represented from Inglis IA. A partial left ramus, UF
12941, is known from El Jobean. An additional fragmentary specimen from
Inglis IA, UF 12931, preserves the left condyle and a portion of the angle
(Fig. 5A, Table 2). TRO 1665 and UF 20065 display enlarged flanges which
project ventrally below the rectangular symphysis. In both specimens the
flange presents a broadly expanded margin. Among the Port Kennedy
specimens, the ventral margin of the flange is noticeably thinner than in the
Florida material. One or two large foramina and numerous small foramina
perforate the concave anterior surface of the symphysis. Two mental
foramina are present on the lateral surface. The smaller, less distinct one is
located on the midline of the ramus below the diastema, and a second is
positioned several millimeters behind it. A deep masseteric fossa extends to
below the posterior root of M1.
The coronoid process is small and not well developed. The
articular surface of the condyle is widest at its medial end. The angle is
situated a short distance from the condyle, and its medial surface presents
well marked grooves for insertion of the M. pterygoideus complex. The
medial surface of the ramus bears a shallow groove (Fig. 5B) above the
geniohyal depression, which is much better developed in Megantereon
(Berta and Galiano 1983). In occlusal view (Fig. 5C), behind the canine
diastema, the cheek teeth are closely set and the superior border of the
mandible containing them is arched laterally.
UF 20065 preserved the 13 alveolus, which indicates that this tooth
was small and transversely compressed (Table 3). The canine is represented
only by the alveolus, which suggests that the tooth curved laterally and was
obliquely oriented in the jaw. Relative to the upper canine, the
corresponding lower tooth was considerably smaller and separated from P3
by a diastema.
The cheek teeth are rectangular with broadly rounded anterior and
posterior margins. P3 is preserved in a ramal fragment, UF 18104, and in a
more complete ramus, UF 18102 (Table 3). It is elongate and double
rooted with a smaller anterior root and a single, centrally positioned
principal cusp. One specimen shows development of a small posterior
cusplet between the principal cusp and the cingular heel. A small diastema
is present between P3-4 in all specimens, with the exception of UF 18102.
Variation in the morphology of P was noted among the Port Kennedy
specimens. In ANSP 44, P3 is small and single rooted. This same tooth in


0 1 2 3 4 5cm
I I I I i J

Figure 5. Left ramus, TRO 1665 of Florida Smilodon gracilis from Inglis IA. (A)
lateral; (B) medial; (C) occlusal views.


ANSP 49, as determined from the alveolus, is similar to the Florida
specimens in its larger size and double-rooted condition. Both single- and
double-rooted conditions of P3 are present in S. populator, and absence of
this tooth is common among late Pleistocene individuals (Berta 1985).
P4 and M1 are represented in the following rami: UF 18103, UF
18104, TRO 1665, UF 20065, and UF 12941 from Inglis IA. A specimen
from McLeod, F:AM 95522, preserved P4-M1 in a ramal fragment. The
principal and accessory cusps of these teeth are inclined posteriorly. P4
consists of a large principal cusp flanked by subequal anterior and posterior
cusplets (Fig. 5, Table 3). The anterior cusplet is medially oriented. Behind
the posterior cusplet a strong lingual cingulum forms the heel of the tooth.
In S. populator this cingulum is less pronounced and a relatively large
second posterior cusplet is present. UF 20065 displays small wear facets on
the labial surface of the anterior cusplet and the principal cusp. F:AM
95522 has a prominent wear surface developed on the labial side of the
principal cusp and the posterior cusplet. The anterior margin of M1
overlaps the posterior border of P4. In M1 the protoconid blade is longer
and taller than the paraconid blade. Pronounced shearing surfaces are
present on the labial surfaces of both the paraconid and protoconid blades.
A small talonid is developed on the M1 heel.
Juveniles are represented in the Inglis IA sample by deciduous
dentitions. The upper milk dentition is represented by UF 18101, a left
dP3 (Table 4), and several frag entary canines, UF 12930 and UF 12929.
The milk carnaisial, dP is triangular and three rooted. Principal
differences between dP and its replacement in the permanent dentition,
P4, are its smaller size and cusp orientation. The protocone is well
separated from the body of the tooth, and it is oriented perpendicular to the
paracone. Relative to the condition seen in adults, the parastyle is medially
positioned. A small ectoparastyle is present. Wear surfaces are developed
on the superior border of the parastyle-metaityle blade and as a small pit
between the protocone and parastyle. In a dP of Megantereon megantereon
from St. Vallier, France (Viret 1954, pJ. 13, fig. Ib) the protocone is in an
anterolingual orientation. Another dP in a juvenile M. megantereon palate
from Puebla de Valverde, Spain (Kurt6n and Crusafont-Pairo, 1977:21, fig.
13), differs from the Inglis specimen in its larger size and lack of a
The lower milk dentition is represented by more material. UF
18105a, a fragmentary left ramus, preserves the deciduous canine alveolus,
dP 4, and a permanent incisor and canine are present in the crypt (Fig. 6,
Table 4). A very fragmentary right ramus, UF 18105b, preserves the dP3
alveolus and dP4. UF 12932, a fragment of the symphyseal portion of the
right ramus, preserves the P2 alveolus and the permanent 13 and C in the
crypt. The most complete specimen, UF 18105a, is similar to adult
individuals. dP3 is separated from the canine by a diastema. In the



Figure 6. Radiograph of juvenile mandibles and dentition of Florida Smilodon
gracilis from Inglis IA. (A) lateral view of left ramus, UF 18105a, with deciduous canine
alveolus, and permanent I and C in the crypt, dP3-4 ; (B) medial view of right ramus, UF
12932, with P2 alveolus and a permanent 13 and C in the crypt.


permanent dentition this tooth is replaced by P2. dP3 is double rooted and
high crowned with sharp, pointed cusps. As in adults, the principal cusp is
flanked by anterior and posterior cusplets. Behind the posterior cusplet, a
cingular heel is developed. The sectorial tooth, dP4, closely resembles M1,
but it differs in exhibiting two progressively smaller cusps behind the
protoconid. The stage of tooth eruption seen in this specimen compares
well with that seen in two juvenile S. populator individuals from Rancho La
Brea, California (Merriam and Stock 1932, pl. 4, table 11).
Comparison of stages of dental eruption in another machairodont,
Homotherium serum from Friesenhahn Cave, Texas, suggests that the
Florida S. gracilis juvenile, UF 18105a, was probably between four and eight
months of age at the time of death. This specimen represents an
intermediate stage between Stage I and IV in the Homotherium eruption
sequence characterized by complete eruption of the deciduous dentition
and emergence of enamel caps for permanent incisors and canines (Rawn-
Schatzinger 1983).
POSTCRANIAL SKELETON.--Much of the skeleton of Smilodon
gracilis is represented by isolated elements from the McLeod and Inglis IA
samples (for individual numbers see Referred Material). The axial skeleton
is represented by cervical vertebrae II and III. In the forelimb, the
humerus, ulna, radius, scapholunar, and metacarpals II, III, IV, and V are
known; and in the hindlimb, the femur, tibia, patella, astragalus, calcaneum,
cuboid, navicular, metatarsals III, IV, and V, and the proximal and median
phalanges are represented. These elements are assigned to S. gracilis with
certainty, because they were collected from sites with dental remains
referred to this species and they resemble but are much smaller than
specimens referred to S. populator. In addition to the machairodont cats,
Megantereon and Smilodon populator, comparisons are made with two true
cats, the jaguar, Felis onca, and the extinct giant jaguar-like cat, Felis atrox.
In size and appearance, especially the relative shortness and stockiness of
the limbs, the jaguar is a good functional analogue for smilodontine
sabercats (see Gonyea 1976).
An axis vertebra, UF 69921, from Inglis IA exhibits a diagnostic
feature of the genus, posterior projection of the neural spine. Additionally,
the posterior termination of the spine is transversely expanded. In Felis
onca the neural spine does not extend as far back, and it has a narrower
termination. The odontoid process of the Inglis specimen, as is
characteristic of Smilodon, is relatively shorter and broader than in Felis
onca .
Cervical vertebra III UF 45342 from Inglis IA possesses two
prominent hyperapophyses that project beyond the posterior zygopophyses,
as is characteristic of smilodontines. These processes appear as small,
rounded tubercles that terminate above the zygopophyses in F. atrox and F.
onca. A depression in the lateral wall of the neural arch in front of the


posterior zygopophysis is present. A similar depression is lacking in S.
populator and F. onca, although small nutrient foramina are seen in this
region. Measurements for UF 45342 are as follows: greatest length from
ends of anterior zygopophyses to ends of hyperapophyses, 62.0; greatest
width across transverse processes, 118.8; greatest depth from posterior
border of centrum to top of neural spine, 68.0.
The most abundantly represented skeletal element in the Florida
sample of S. gracilis is the humerus (Fig. 7, Table 5). Two complete humeri,
TRO 1670 and UF 18106, are represented from Inglis IA, and three distal
humeri, UF 18107 (2) and F:AM 95523, are known from Inglis IA and
In proximal view (Fig. 7A), the medial border of the greater
tuberosity bears a smaller tubercle than that of Felis atrox, which results in a
more open channeled bicipital groove in the sabercat. This tubercle and the
greater tuberosity serve as areas of insertion for the anterior part of the M.
pectoralis profundus which retracts and adducts the forelimb and the M.
supraspinatus which extends the shoulder joint. In anterior view, the
pectoral crest is prominent at the proximal end of the shaft and onto this
surface inserts the descending and transverse parts of the M. pectoralis
In posterior view (Fig. 7B), the transverse breadth of the distal
extremity in smilodontines is especially striking and is reflected in the ratio
of humerus length to distal width. Schaub (1925) noted that this ratio in a
true felid, Panthera tigris, approximated 4.0 compared with a ratio of 3.2 in
Megantereon cultridens. The same ratio is 3.6 in S. gracilis and 3.2 in S.
populator. The olecranon fossa, which receives the anconeal process of the
ulna, is relatively deep in S. gracilis and typically transversely broad,
although its shape is somewhat variable. In posterior and medial views, the
lesser tuberosity is elevated on a distinct pedicel, and a prominent crest
marks its medial boundary. It projects medially to a greater degree than in
S. populator and is most similar to the condition seen in Megantereon
cultridens (Schaub 1925, fig. la). The proximal portion of the shaft in
medial view displays a linear roughened area of attachment for the M. teres
major. A small distally directed nutrient foramen is positioned near the
medial border of the shaft above the oblong entepicondylar foramen. The
distal extremity of one specimen, TRO 1670, clearly illustrates on the
prominent medial epicondyle areas of origin for flexors of the forelimb.
Onto the superior broadly rounded projection originates the M. pronator
teres. Below this prominence are facets for insertion of M. flexor carpi
radialis and flexorprofundus digitorum and behind these facets is another for
the M. palmaris longus.
The lateral profile of the greater tuberosity (Fig. 7C) is diagnostic
in smilodontines. The juncture of the greater tuberosity and the anterior
border of the shaft is nearly orthogonal in Smilodon and Megantereon


0 1 2 3 4 5cm


I -I

/ -.--y


Figure 7. Right humerus, UF 18106, of Florida Smilodon gracilis from Inglis IA.
(A) proximal; (B) posterior; (C) lateral views. (a) bicipital groove, (b) lesser tuberosity, (c)
olecranon fossa, (d) greater tuberosity, (e) for insertion of M. teres minor, (f)
supracondyloid crest, (g) for insertion of lateral ligament, (h) for origin of M. extensor carpi
radialis and M. extensor communis digitorum, (j) deltoid crest, (k) for insertion of M.


(Schaub 1925), while in true cats these surfaces form an arcuate connection.
The depression for insertion of M. infraspinatus is at the same level as the
head of the humerus in both smilodontines and F. onca The position of
the insertion of this muscle relative to the head of the humerus has the
effect of increasing the abductor function, and because the insertion is not
parallel to the sagittal plane of this element, the rotary function is increased.
Below that is a rugose quadrate area for insertion of the M. teres minor, well
defined in all S. gracilis and similar to the degree of development in F. onca.
By comparison, the M. teres scar in S. populator is smaller and not well
developed. As the action of this muscle is one of flexion and abduction of
the forelimb, the gracile sabercat was probably capable of greater forelimb
mobility than the late Pleistocene species. The deltoid crest originates
below the infraspinatus depression and extends anteriorly as a well
developed ridge to its junction with the pectoral ridge (see Fig. 7C). The
deltoid crest is the most prominent feature of the lateral surface of the shaft
in both S. gracilis and S. populator and provides insertion for the M.
deltoideus. One specimen, TRO 1670, exhibits an irregular bony growth on
the anterolateral surface of the shaft, perhaps the result of a secondary
calcification within a tendon. The posterolateral border of the shaft forms a
sharp crest, the supracondyloid ridge from which originate muscles that act
to rotate and extend the forelimb. The M. supinator originates on the
proximal portion of this ridge. Near the distal end of the ridge is a
prominent, ovate muscle scar which probably afforded attachment for the
Mm. extensor carpi radialis and extensor communis digitorum. Below this
elongate facet is a small, short area of origin for the M. extensor digitorum
lateralis. The lateral ligament inserts below this onto the distal surface of
the lateral epicondyle.
Two proximal left ulnae, F:AM 95524 and F:AM 69223 (without
olecranon process), and two right ulnae, UF 18109, are represented from
McLeod and Inglis IA (Fig. 8, Table 6). In proximal view, the olecranon
process is quadrate and broader than in true cats. The posterior surface is
the area of insertion for the scapuluar head of the M. triceps. As noted by
Merriam and Stock (1932:115), the broadened olecranon process among
smilodontines also furnishes a longer area of insertion for the posterior
humeral head of the M. triceps. There are significant differences in the
degree of development of the lateral and medial margins of the olecranon
fossa in both S. gracilis and F. onca (Fig. 8B). Among these cats, the high,
strongly developed lateral margin affords a broader area of insertion for the
lateral head of the M. triceps than does the lower, less developed medial
margin where the medial head of the M. triceps inserts. By comparison, in
S. populator the lateral margin is heavy but not as prominently developed
relative to the medial margin. Because the M. triceps functions to extend
the elbow joint, its stronger degree of development in S. gracilis provides


further evidence of increased flexibility and more powerful extension of the
forelimb in this sabercat.
The coronoid process is directed proximally and laterally, not
distally as in true cats (Fig. 8A). The distal two-thirds of the shaft is
represented only by F:AM 69223. In lateral view, a longitudinal muscle scar
for origin of the ulnar head of the M. flexor profundus digitorum is
positioned on the medial margin. As illustrated in this view, the posterior
margin of the proximal end in both Smilodon and Megantereon (Schaub
1925) displays a relatively straight edge in contrast to the strongly curved
margin exhibited by true cats.
Both a right and a left radius, F:AM 69219 and F:AM 69220, are
known from McLeod and a left radius, UF 18108, is represented from Inglis
IA (Fig. 9, Table 6). In contrast to true cats, the short diameter (transverse
width) of the head is greater and provides a broader articulating surface for
the humerus. In lateral view, the margin of the articular surface is slightly
rounded and noticeably downturned.
On the anterior surface of the shaft (Fig. 9A) a slight swelling is
developed for insertion of the M. supinator which acts to rotate the
forelimb. This facet appears flattened and less prominent in S. populator
and F. onca. In this view the distal end presents a concave surface for
articulation with the scapholunar. Its medial one-half is anteroposteriorly
broader than in true cats.
On the posterior surface (Fig. 9B) positioned a short distance
below the head is a prominent linear, ovate swelling, the bicipital tuberosity.
Below this tuberosity is a roughened area of origin for the M. abductor
pollicis longus. In this view, the oblique line which rises from the lower one-
third of the tuberosity and passes from the proximal lateral margin across
the posterior surface to an insertion point on the medial margin is well
defined on F:AM 69219. This broad area, defined by the oblique line and
the medial margin, suggests development of a large flexor of the forepaw,
the M. flexor digitorum profundus. Below the insertion point of this muscle
on the medial margin is a prominent roughened area for insertion of the M.
pronator teres.
The shaft is short and slightly curved and in comparison with S.
populator, relatively slender. Medially positioned on the distal extremity is
the wedge shaped, anteromedially broad styloid process. The distal end of
this surface bears three distinct grooves for extensors of the forepaw. The
most medial groove is deep and lodges the tendon of M. abductor pollicis
longus. The middle groove, the largest and shallowest, contains the tendon
of the M. extensor carpi radialis. The most lateral groove, which is broad
and shallow when compared with true cats, holds the tendon of the M.
extensor digitorum communis.
A left scapholunar, F:AM 108538 (Fig. 10), has a rectangular and
anteroposteriorly convex proximal surface. The ulnar half is broadly


0 1 2 3 4 5cm
I 4 I I I I

Figure 8. Right ulna, UF 18109, of Florida Smilodon gracilis from Inglis IA. (A)
lateral; (B) anterior views. (a) olecranon process, (b) trochlear notch (c) coronoid process.



f /

/ \' I

li]! II,

e d

0 1 2 3 4 5cm
Figure 9. Left radius, F:AM 69220, of Smilodon gracilis from McLeod. (A)
anterior; (B) posterior views. (a) for insertion of M. supinator; (b) for origin of M. abductor
pollicis longus, (c) for insertion of M. extensor digitorum communis, (d) for insertion of M.
extensor carpi radialis, (e) for insertion of M. abductor pollicis longus, (f) for insertion of
M. pronator teres, (g) bicipital tuberosity, (h) oblique line, (i) for insertion of M. flexor
digitorum profundus, (j) styloid process.


rounded, whereas the radial half is elevated to a sharp crest that is
continuous with projection of this element into a distinct proximal process
(Fig. 10A).
In anterior view, the depth of the element toward the ulnar side is
less than in true cats. The ulnar border presents three emarginations which
are the edges of the articular cavities for the uniform, magnum, and
trapezoid. On the proximal process is positioned a triangular facet for
articulation with the sesamoid. In posterior view, this element appears
nearly rectangular. The surface is flat except for the proximal process where
a deep groove is present for passage of the tendon of the M. flexor carpi
radialis which is responsible for flexion of the wrist. In lateral view, the
crescentic facet for the uniform is narrow anteroposteriorly and does not
show an increase in width toward the radial side as in true cats.
Four irregularly shaped facets which articulate with the distal
carpals are conspicuous in distal view (Fig. 10B). The smallest of these
facets is that for the sesamoid. Behind this facet is that for the trapezium
and trapezoid which are separated by a ridge. The trapezoid facet in S.
gracilis is broader mediolaterally and extends farther toward the posterior
border than in S. populator. Separating the trapezoid from the deep
concavity for the magnum is a small pit which provides a point of insertion
for a ligament. The magnum facet passes laterally into the distal-facing
crescentic uniform facet. Measurements for F:AM 108538 are as follows:
anteroposterior diameter, 34.8; transverse diameter, 44.7; proximodistal
diameter, 25.7.
A b B

0 1 2 3 4 5cm

Figure 10. Left scapholunar, F:AM 108538, of Florida Smilodon gracilis from
McLeod. (A) proximal; (B) distal views. (a) for articulation with radius, (b) proximal
process, (c) for articulation with trapezium, (d) for articulation with sesamoid, (e) for
articulation with magnum, (f) for articulation with uniform, (g) for articulation with


The metacarpals are relatively short and robust in comparison with
those of a similar sized true cat. Both a right (UF 17498) and a left (UF
12934) metacarpal II are represented from Haile XVA and Inglis IA (Fig.
11A, B, Table 7). The proximal surface that articulates with the the distal
end of the trapezoid lacks the strongly triangular shape seen in true cats.
In anterior view (Fig. 11A), the oblique groove for the radial artery is
prominent. Medially, the swelling for insertion of the tendon of the M.
extensor carpi radialis, which functions to extend and abduct the forepaw, is
more pronounced than in true cats. In medial view (Fig. 11B), the facet for
the trapezium is elongate proximodistally and elevated above the remaining
part of the anterior facet accentuating the strong depression adjacent to it.
A similar projection of the trapezium was noted by Vrba (1981) in
Megantereon white from Kromdraai, South Africa. In true cats, projection
of the trapezium only slightly interrupts the general concavity of the surface.
In lateral view, the shape of the metacarpal facet is broad and elongate
proximodistally, as is characteristic of the genus. A facet for the magnum is
A left metacarpal I, UF 45409, is known from Inglis IA (Fig. 11C,
D, Table 7). The proximal surface which articulates with the magnum is
broadly concave. Along its lateral border is a rectangular facet for the
uniform. Presence of this facet is diagnostic in smilodontines and F. onca.
A deep, broad notch defines the medial border of the proximal surface in
contrast to the acute, shallow notch in F. atrox and F. onca. In medial view,
the anterior facet for metacarpal II is flat, and it has a more nearly
longitudinal axis in contrast to the oblique axis in Felis atrox and F. onca. In
lateral view (Fig. 11D), above the broad concavity for articulation with
metacarpal IV, is the uniform facet. Below this concavity is a roughened
area for origin of the M. interosseous.
Metacarpal IV is represented by UF 18110 and F:AM 69249 from
Inglis IA and McLeod (Fig. 11E, F, Table 7). As is characteristic of the
genus, the posterior side of the proximal end is not as broad as in true cats.
The anterior border is notched near the middle. In anterior view (Fig.
11E), a diagnostic feature of this genus is apparent. The uniform surface
forms a sharp angle with the plane of the surface for metacarpal III. In F.
onca this angle is less prominent, and in F. atrox no sharp distinction
between these surfaces exists. In medial view, a notch is present in the
convex articulating surface for metacarpal III. Below this surface the shaft
is slightly roughened for ligament attachments.
In lateral view (Fig. 11F), the articular surface for metacarpal V is
prominent. Perhaps the most useful character separating this species from
S. populator is the structure of the palmar hook. In S. gracilis the hook is
flattened at the base. In S. populator it is bulbous and projects ventrally
from the base. Extending from the proximal border of the hook to the


medial portion of the shaft is a prominent roughened area for origin of the
M. interosseous.
UF 12935, a right metacarpal V from Inglis IA, is particularly short
and robust (Fig. 11G, H, Table 7). The rounded proximal surface which
articulates with the uniform is broad. Its curved lateral border (Fig. 11G)
passes onto the roughened tuberosity of the proximal end. Onto this
tuberosity attach ligaments and the M. extensor carpi ulnaris which functions
to extend and abduct the forepaw. In medial view (Fig. 11H), the notch
which incises the margin of the articulating facet for metacarpal IV is broad
rather than narrow as in true cats. The posterior side forms a prominent
hook. The shaft is flattened posteriorly and the median border of the distal
end is sharply keeled.
A proximal right femur, UF 18112, is represented from Inglis IA
(Fig. 12, Table 8). In proximal and posterior views (Fig. 12B), the head is
hemispherical and at the same elevation as the pyramid-shaped greater
trochanter. The greater trochanter is medially inclined relative to the
anteroposterior axis of the shaft. The posterior surface serves as a broad
area of attachment for extensors of the hip, the Mm. gluteus, medius,
minimus, and pyriformis. The trochanteric fossa is large, though not as
broad anteroposteriorly as in S. populator. True cats are usually
distinguished in having a narrow, more restricted fossa. As is characteristic
of smilodontines, a rounded prominent tuberosity is positioned between the
head and the trochanteric fossa (see Fig. 12A, B). This tuberosity is less
developed in true cats. The large lesser trochanter is directly below the
tuberosity, a more medial position than in true cats. The tendon of the
combined M. psoas and iliacus, extensors of the hip, insert on its apex. The
posterior intertrochanteric crest which separates the fossa from the greater
trochanter appears transversely rounded rather than flattened and angular
as in true cats. On the upper part of this crest are areas of insertion for the
M. gluteus medius and, below that for the M. quadratus femoris. Also
apparent in posterior view (Fig. 12B) is the anterior intertrochanteric line
which extends from the neck obliquely to its junction with the linea aspera
below the lesser trochanter. It marks the upper border of the area of origin
for M. vastus extemus, an extensor of the hip joint.
A right patella, F:AM 108538, is represented from McLeod (Fig.
12). Most of the posterior surface is occupied by a concavo-convex articular
facet for the trochlea of the femur (Fig. 12C). The distal end is broadly
rounded. In lateral view (Fig. 12D), the anterior surface, which bears
longitudinal striae, is strongly arched at its proximal end, becoming gently
convex distally. The great proximal depth of this element is a diagnostic
generic character. Measurements for F:AM 108538 are as follows: greatest
anteroposterior diameter, 22.0; greatest transverse width, 34.8; greatest
proximodistal diameter, 41.9.


0 1 2 3 4 5cm




S0 1 2 3 4 5cm

Figure 12. Right proximal femur, UF 18112, of Florida Smilodon gracilis from Inglis
IA. (A) proximal; (B) posterior views. (a) prominent tuberosity, (b) greater trochanter, (c)
lesser trochanter, (d) anterior intertrochanteric line, (e) interochanteric fossa. Right
patella, F:AM 108538, of Florida Smilodon gracilis from McLeod. (C) posterior; (D) lateral
Figure 11. Right metacarpal II, UF 17498, of Florida Smilodon gracilis from Haile
XVA. (A) anterior; (B) medial views. (a) for articulation with trapezoid, (b) radial artery,
(c) for articulation with trapezium, (d) for insertion of M. extensor carpi radialis. Left
metacarpal III, UF 45409, from Inglis IA. (C) anterior; (D) lateral views. (e) for
articulation with magnum, (f) for origin of M. interosseous, (g) for articulation with
uniform, (h) for articulation with metacarpal IV. Right metacarpal IV, UF 18110, of
Florida Smilodon gracilis from Inglis IA. (E) anterior; (F) lateral views. (i) for articulation
with uniform, (j) for articulation with metacarpal III, (k) for articulation with metacarpal
V, (1) for origin of M. interosseous. Right metacarpal V, UF 12935, of Florida Smilodon
gracilis from Inglis IA. (G) anterior; (H) medial views. (m) for articulation with uniform,
(n) for insertion of M. extensor carpi ulnaris, (o) for articulation with metacarpal IV.


A right and a left distal tibia, UF 17496 and F:AM 95529, are
represented from Haile XVA and McLeod (Fig. 13, Table 8). In anterior
view (Fig. 13A), a relatively shallow notch defines the medial border of the
distal extremity in contrast to the much deeper notch developed in true cats.
In posterior and medial views (Fig. 13B, C), the shaft of F:AM
95529 displays a strong vertical keel. This portion of the shaft is typically
only slightly convex. Distally, the shaft is noticeably flattened as in S.
populator. The medial malleolus in Smilodon and Megantereon cultridens
projects farther distally than in true cats. Also noted in posterior view is a
large, well defined deep groove on the medial malleolus for the tendon of
M. tibialis caudalis, which is responsible for extension of the tarsus and
outward rotation of the foot. A prominent ridge separates the course of the
medial tendon of the M. flexor digitorum longus from the lateral tendon of
the M. flexor hallucis longus, which function as flexors of the tarsus and
extensors of the digits. In distal view, as is characteristic of smilodontines,
the articular surface for the astragalus is anteroposteriorly broad. A
triangular facet for articulation with the fibula exists on the extreme
posterolateral corner of the element.
One right astragalus, TRO 1666, and three left astragali, UF 17496,
TRO 1667, and F:AM 108536, are known from Inglis IA, Haile XVA, and
McLeod (Fig. 14, Table 9). In anterior view (Fig. 14A), this element is
characteristic of smilodontines and F. onca in having a short, broad neck
and a shallowly grooved trochlea. The anteromedial border of the head
extends farther distally on the neck than in true cats. A similar observation
was noted by Schaub (1925) for Megantereon cultridens. The shape of the
head is flattened and less hemispherical among smilodontines in
comparison with true cats.
In posterior view (Fig. 14B), are two articular facets for the
calcaneum. The sustentacular facet is connected by a narrow strip to the
navicular facet in this species and F. onca. Between these facets is a small
ovoid pit for attachment of a ligament. In S. populator a much broader
connection between these facets is developed. In the extinct cat F. atrox
and the Recent cats F. leo and P. trigris, these facets are separate articular
facets, and the ligamental pit is deeper. A deep, oblique groove separates
these articular surfaces from the astragalocalcanear facet on the lateral half
of the element. An astragalar foramen, present in three specimens in the
distal portion of the groove, is absent in true cats.
Four right calcanei; TRO 1668, F:AM 95534, F:AM 95532, and UF
24000; and four left calcanei; F:AM 95533, UF 12936, UF 12937, UF 18113,
and UF 23999; are known from Inglis IA and McLeod (Fig. 15, Table 10).
In anterior view (Fig. 15A) the most diagnostic feature is apparent, the
orientation of the sustentacular and navicular facets relative to the cuboid
border. In F. atrox, these facets are well separated from one another. In S.
populator, these facets are adjacent and their articular surfaces broadly


joined. In S. gracilis and F. onca, a narrow articular strip connects these
facets. The large, concave astragalocalcanear facet in Smilodon usually does
not encroach upon the short, robust calcanear tuber as far as in true cats. A
prominent groove for transmission of the tendon of the M. peroneus longus,



\ '


9 ~ 4 cm f

!. i?'

' I'1,

Figure 13. Left distal tibia, F:AM 95529, of Florida Smilodon gracilis from McLeod.
(A) anterior; (B) posterior, and (C) medial views. (a) shallow notch, (b) keel, (c) lateral
malleolus, (d) medial malleolus, (e) for origin of M. flexor hallucis longus, (f) for origin of
M. flexor digitorum longus, (g) for origin of M. tibialis caudalis.


r 0 1 2 3 4 5cm f

Figure 14. Left astragalus, F:AM 17496, of Florida Smilodon gracilis from Haile
XVA. (A) anterior; (B) posterior views. (a) neck, (b) tibial trochlea, (c) astragalocalcanear
facet, (d) astragalar foramen, (e) sustentacular facet, (f) navicular facet.

0 1 2 3 4 5cm

Figure 15. Left calcaneum, F:AM 95533, of Florida Smilodon gracilis from McLeod.
(A) anterior; (B) distal views. (a) sustentacular facet, (b) navicular facet, (c) astragalar
facet, (d) astragalocalcanear facet, (e) cuboid facet.


which functions in version and abduction of the foot, is positioned on the
lateral margin of the calcanear tuber. This groove is present, although less
well developed, in true cats with the exception of the jaguar. The
sustentaculum is elevated only a short distance above the distal end, a
diagnostic feature of smilodontines. The proximal portion of this element
in lateral view is marked by a distinct pit for insertion of the external lateral
ligament. At the distal end a deep groove, which transmits the tendon of
the M. peroneus longus, crosses the lateral surface. In distal view (Fig. 15B),
the articular surface for the cuboid is distinctly concave and pierced by
numerous foramina. A small triangular facet for the navicular, absent in
true cats, is usually present on its medial margin.
A right cuboid, F:AM 105838, from McLeod (Fig. 16) has a
roughly rectangular proximal surface with nearly straight dorsal and medial
margins (Fig. 16A). The posterior border is emarginate to a greater degree
than in true cats. This surface is slightly convex and articulates with the
distal end of the calcaneum. In medial view (Fig. 16B), the navicular facet
occupies the dorsoplantar corner of the cuboid. In this specimen two facets
provide articulation for the ectocuneiform. As noted by Jayne (1898), these
facets are subject to variation; in both Smilodon and true cats they are
joined together in a single crescentic facet which, in Smilodon, is positioned
farther distally than in true cats. Also illustrated in this view is the shorter
proximodistal diameter of the element when compared with true cats.
In posterior view the cuboid is divided into two parts by an oblique
groove which provides passage for the tendon of the M. peroneus longus.
Proximal to this groove is a prominent tuberosity on which flexors of the
digits originate, the Mm. adductor indicis, adductor digiti minimi, and the
opponents digiti minimi. Medial to the tuberosity is a concavity roughened
for the insertion of a ligament. A characteristic of the genus is seen on the
distal face of the cuboid; the articular facet for metatarsal IV is smaller than
this same facet in true cats. The facet for metatarsal V in Smilodon is larger
than the same facet in true cats. Measurements for F:AM 105838 are as
follows: anteroposterior diameter, 23.7; transverse diameter, 25.2;
proximodistal diameter, 24.5. In a right navicular, F:AM 95521, from
McLeod (Fig. 16), most of the proximal surface is occupied by the concave,
oblong facet for the distal end of the astragalus (Fig. 16C). This facet is
slightly deeper than in true cats.
In lateral view (Fig. 16D), another unique generic character is
visible. In addition to the presence of a triangular, flat facet for articulation
with the cuboid, a small, convex facet for the calcaneum is positioned
proximal to the former facet. The calcanear facet is absent among true cats.


The proximal plantar tuberosity is more strongly developed than in
Smilodon populator. The medial side presents no articular facets and is
oblong and convex.
The rectangular distal surface displays rounded margins. The
posterolateral portion is roughened for attachment of interosseous
ligaments, and the remainder of the surface is occupied by articular facets
for the cuneiform bones. The largest facet, for the ectocuneiform occupies
the dorsolateral portion of the element. It is not as broad dorsolaterally as
in true cats, and the dorsolateral margin is angular rather than broadly
rounded. A deep pit for insertion of a ligament exists posteromedially. A
small round facet for articulation with the proximal surface of the
ectocuneiform separates this pit from the medial margin. Dorsal to this
facet is a slightly larger facet, which articulates with the proximal surface of
the mesocuneiform. Measurements for F:AM 95521 are as follows:
anteroposterior diameter, 37.3; transverse diameter, 26.0.

c e f

b 0 1 5cm

Figure 16. Right cuboid, F:AM 105838, of Florida Smilodon gracilis from McLeod.
(A) proximal; (B) medial views. Anterior is to the left. (a) for articulation with calcaneum,
(b) for articulation with ectocuneiform, (c) for articulation with navicular. Right navicular,
F:AM 95521, of Florida Smilodon gracilis from McLeod. (C) proximal; (D) lateral views.
Anterior is to the left. (d) for articulation with astragalus, (e) proximal plantar tuberosity,
(f) for articulation with calcaneum, (g) for articulation with cuboid.

Figure 17. Left metatarsal III, UF 12939, of Florida Smilodon gracilis from
McLeod. (A) anterior; (B) lateral views. (a) articulation with ectocuneiform, (b) for
articulation with metatarsal IV, (c) for insertion of ligament. Right metatarsal IV, UF
12940, of Florida Smilodon gracilis from Inglis IA. (C) anterior; (D) medial views.
(d) for articulation with metatarsal III. Right metatarsal V, F:AM 95531, of Florida
Smilodon gracilis from McLeod. (E) anterior; (F) medial views. (f) proximal tuberosity for
articulation with cuboid, (g) for articulation with metatarsal IV.

0 1 2 3 4 5cm


As is true of the metacarpals, the metatarsals are relatively short
and robust. Metatarsal III (UF 12939, F:AM 69241) is represented from
Inglis IA and McLeod (Fig. 17A, B, Table 11). The proximal surface is T-
shaped and the arm extends posteriorly. The posterior portion of the arm is
transversely broader and shorter than in true cats. In anterior view (Fig.
17A), the proximal surface, which articulates with the ectocuneiform, is
nearly flat and slopes medially.
In medial view, two facets which articulate with metatarsal II are
separated by a groove. The posterior facet is obliquely oriented, whereas in
true cats the axis is longitudinal. Below these facets on the shaft are
roughened areas for insertion of ligaments binding this element to
metatarsal II. In lateral view (Fig. 17B), are positioned two facets which
articulate with metatarsal IV. As is characteristic of the genus, the larger
posterior facet extends farther ventrally and proximally, forming a broad
surface of attachment. Below these facets are prominent rugosities for
ligament attachments. The medullary foramen is proximally positioned on
the shaft.
Metatarsal IV (UF 12940, F:AM 95530, and F:AM 69243) is
known from Inglis IA and McLeod (Fig. 17C, D, Table 11). The proximal
surface for articulation with the cuboid is rectangular and less extensive
than in true cats (Fig. 17, Table 11). The proximal surface for articulation
with the cuboid is rectangular and less extensive than in true cats (Fig. 17C).
In Smilodon the posterior tuberosity extends for a considerable distance
behind the posterior margin of the cuboid facet.
In medial view (Fig. 17D), at the proximal end, is an ovoid anterior
facet and a rectangular posterior facet for articulation with metatarsal V.
These facets are separated from one another by a groove. In lateral view
one large posterior facet and a small anterior facet, both rectangular,
provide articulation surfaces for metatarsal III. In S. gracilis the posterior
facet is considerably smaller in the anteroposterior dimension. The anterior
facet is situated on a distinct pedicel and separated from the posterior
tuberosity. Below the posterior facet is a linear roughened area for origin of
the M. interosseous.
A right metatarsal V, F:AM 95531, is represented from McLeod
(Fig. 17, Table 11). The proximal surface is triangular. The anterior view
(Fig. 17E) is characteristic of the genus: the proximal tuberosity is not
flattened and elongate as in true cats, rather it is rounded and shortened
proximodistally. In S. populator this tuberosity is less pronounced. A notch
is present along its posterior margin. The stoutness of the shaft and its
degree of curvature are well illustrated in this view. In medial view (Fig.
17F), two facets for articulation with metatarsal IV are positioned below the
flattened articular facet for the distal end of cuboid. In S. gracilis, the
separation between the cuboid facet and the posterior metatarsal IV facet is


sharp and angular. In S. populator, these two facets, although separated by
a sharp ridge, are broadly convex. Below the posterior articular facet is a
prominent tendon scar.
Of the three proximal phalanges represented from McLeod, F:AM
95535a is assigned to the second digit of the left forepaw; F:AM 95535b and
F:AM 95535c are assigned to the second and third digits of the right
hindpaw, respectively (Fig. 18 A-F, Table 12). These assignments are based
on relative size, degree of curvature, and shape of the proximal surface of
the element. In posterior view, the lateral and medial sides of the shaft of
all proximal phalanges are marked near their distal ends by ovate
roughened tendon scars. F:AM 95535a displays an arcuate anterior border
on the proximal surface and a narrowly incised posterior border. The shaft
is arched lateromedially. F:AM 95535b exhibits an arcuate border that
gives way to a sharply angular posteromedial border on the proximal
surface. The posterior surface is broadly notched which, along with the
greater transverse width of the shaft, identifies this element as belonging to
the hindpaw. F:AM 95535c displays an arcuate anterior border and a
narrowly notched posterior border. The shaft is flattened lateromedially,
distinguishing if from F:AM 95535a.
Four middle phalanges are represented from McLeod, F:AM
108537a, F:AM 108537b, F:AM 108537c, and F:AM 108537d, are assigned
to the second, third, fourth, and fifth digits of the left forepaw. The
proximal surface of all middle phalanges is triangular with concave facets for
articulation with the trochlea of the proximal phalanges. The medial border
of the shaft in F:AM 108537a is strongly curved. Arthritic lipping is
displayed on the proximolateral extremity of the shaft. F:AM 108537c is
similar in structure, although somewhat larger, than F:AM 108537b and
shows arthritic lipping on the distal portion of the shaft and articular head.
F:AM 108537d displays a curved median border and a deeply concave shaft


Smilodon gracilis is characterized by the presence of large, slightly
recurved upper canines with long sharp-edged blades that lack strong
serrations. Most traditional reconstructions show sabercats as active
predators killing large prey by stabbing with their elongate canines into the
back of the head or the nape of the neck. As demonstrated in a functional
analysis of sabertooth jaw mechanics, it is more likely that the throat or
neck was the target area where "one slash could sever critical blood vessels
and result in rapid death" (Emerson and Radinsky 1980:308). As Martin
(1980) suggested, sabercats were probably unable to tear flesh directly from





9 1 ? 3 5cm

Figure 18. Left proximal phalanx (digit II, forefoot) F:AM 95535a, of Florida
Smilodon gracilis from McLeod. (A) proximal; (B) anterior views. Right proximal phalanx
(digit II, hindfoot) F:AM 95535b, of Florida Smilodon gracilis from McLeod. (C) proximal;
(D) anterior views. Right proximal phalanx (digit III, hindfoot) F:AM 95535c, of Florida
Smilodon gracilis from McLeod. (E) proximal; (F) anterior views. Left medial phalanx
(digit II, hindfoot) F:AM 108537a of Florida Smilodon gracilis from McLeod. (G) anterior
view. (a) arthritic lipping. Left medial phalanx (digit III, hindfoot) F:AM 108537b, of
Florida Smilodon gracilis from McLeod. (H) anterior view. Left medial phalanx (digit IV,
hindfoot) F:AM 108537c, of Florida Smilodon gracilis from McLeod. (b) arthritic lipping.
Left medial phalanx (digit V, hindfoot) F:AM 108537d, of Florida Smilodon gracilis from
McLeod. (J) anterior view.



the bone, as do other carnivores, because the upper canines would get in
the way. Food was probably taken in to the side of the mouth, an operation
perhaps facilitated by the incisors. Both upper and lower incisors of
sabercats are prognathous, sharply pointed, and recurved, and they probably
served to pull flesh away from the bone. Once in the mouth, food was
processed by elongate shearing blades of the highly modified cheek teeth.
The mandible, with its relatively large flange, served as protection for the
sabers, as noted by Kurt6n (1963) who interpreted reduction of the flange
in S. populator to be the result of the saber biting outside the lower lip.
In comparison with true cats, limbs and feet of the gracile sabercat
reflect differences in form and extent of articular areas, muscle attachment
sites, and relative proportions of the elements themselves. Modifications of
smilodontine felids over true cats were in the direction of power and
flexibility rather than speed.
The importance of the anterior limbs in grasping and holding prey
in sabercats is evident when one considers the lateral forces that occurred
on the canines during the stabbing of struggling prey. The forelimb of the
gracile sabercat was capable of considerable range of motion and
movement. The abductor function of the limbs was increased as judged
from the broad lateral epicondyle and associated musculature and the well
developed M. teres scar on the humerus.
Both S. gracilis and F. onca have an olecranon process with a larger
lateral margin relative to that of the medial margin. According to Gonyea
(1978), among forest adapted felids (e.g. clouded leopard, Neofelis nebulosa,
and jaguar, Felis onca) a large lateral olecranon is correlated with a large
lateral M. triceps, which permits greater mediolateral rotation at the elbow
joint in these cats. The increased supinator-pronator ability of the saber cat
forelimb is further reflected in the laterally positioned larger radial notch
which permitted medial rotation of the wrist during flexion.
Gonyea (1978) correlated shape and position of the olecranon
fossa with habitat preference in a functional study of felid forelimb anatomy.
He demonstrated a greater olecranon angle among those carnivores in
which motion about the humero-ulnar joint is not restricted in the
mediolateral plane. Felids that were exclusively forest dwellers were found
to have a high inclination of the olecranon fossa. The inclination of the
olecranon fossa relative to the longitudinal axis in S. gracilis (N=4) varies
between 230 and 270. This high value suggests that the Florida gracile
sabercat was forest adapted.


Smilodontine felids exemplify the digitigrade posture characteristic
of true cats; however, both Smilodon and Felis onca display several features
of the hindlimbs and feet that are more characteristic of plantigrade felids
(including Hoplophoneus, Eusmilus, and Sansanomilus; see Ginsburg 1961).
Plantigrade features shared by Smilodon and F. onca include relatively
short, stocky limbs, broad area of insertion on the tibia for the M. tibialis
caudalis, development of a large groove on the short calcaneal tuber for
passage of the M. peroneus longus, and short metapodials which, when
articulated, tend to spread out in a fan. These features strongly suggest a
de-emphasis upon cursoriality and an increase in power and flexibility
among these sabercats.
The hindfeet of S. gracilis are significantly larger than the forefeet
(Tables 7 and 12). A similar proportional relationship exists between the
fore- and hindfeet of Megantereon cultridens (Schaub 1925:256). In
contrast, S. populator exhibits more equally proportioned feet (Merriam and
Stock 1932, tables 55-61 and 80-86). The fore and hindfeet of sabercats
were equipped with retractile claws which may have inhanced prey
immobilization and facilitated an accurate canine strike.
Unfortunately the limbs of S. gracilis are incomplete and do not
permit the computation of limb ratios. It has been shown by Gonyea (1976)
that the short, robust limbs and body proportions of S. populator are similar
to those of modern felids that inhabit forested environments. However, this
species seems to be better represented in plains and woodland habitats (e.g.
Rancho La Brea). One of the best known samples of the gracile sabercat,
that from Inglis IA, provides additional evidence for occurrence of this
taxon in open habitats. Gonyea suggested that the success of Smilodon in
low structured habitats may have been a function of its sociality and group
hunting efforts.
The dental and postcranial anatomy of smilodontine felids suggests
that they evolved hunting strategies that relied upon stalking and ambush
rather than rapid pursuit. Limb morphology suggests that they were forest
adapted, although they are better sampled from plains and woodland



Faunal comparisons of tooth and postcranial measurements
between the late Blancan (El Jobean), early Irvingtonian (Inglis IA), and
late Irvingtonian (Port Kennedy, McLeod) localities indicate that late
Irvingtonian specimens average larger and suggest a trend toward size
increase for the gracile sabercat. Kurten (1968) and Kurten and Crusafont-
Pairo (1977) observed a similar increase in size among Eurasian
Megantereon during the Villafranchian (Tables 13, 14). It is also apparent
from these data that S. gracilis was a larger animal than Megantereon.
The upper canines of late Irvingtonian S. gracilis are significantly
larger and broader than those of late Villafranchian Megantereon cultridens,
although sexual dimorphism probably accounts for some of this variation.
A fragmentary upper canine referred to S. populator from Conard Fissure
(late Irvingtonian) is slightly larger the late Irvingtonian S. gracilis. P3 in
late Villafranchian M. cultridens shows a tendency toward reduction in size
when compared with early Villafranchian specimens, although a parallel
trend was not observed among S. gracilis (Table 13).
The lesser size variability of M1 makes it particularly sensitive to
evolutionary increase in body size in mammalian species (Gingerich 1974).
The larger M1 of both late Irvingtonian S. gracilis and late Villafranchian
M. cultridens, relative to earlier specimens of each species, provides the best
evidence for an increase in size of these sabercats through time. The more
derived species, S. populator, is significantly larger than either S. gracilis or
M. cultridens, as demonstrated by comparison of tooth and body
measurements (Tables 13, 14).


Recently Churcher (1984) proposed recognition of Smilodon
gracilis as a junior synonym of species described under Ischyrosmilus, which
he referred to the tribe Smilodontini. This hypothesis differs fundamentally
from the hypothesis of machairodont relationships presented by Berta and
Galiano (1983) and from the views presented here. A comprehensive
systematic revision of the machairodont Felidae is necessary to fully resolve
these differences. Although such a revision is clearly beyond the scope of
this paper, the following discussion will provide a preliminary rebuttal of
Churcher's proposal.
Central to Churcher's systematic hypothesis is his statement that
"All characteristics given by Merriam for species of the genus Ischyrosmilus,
except variation in size, are descriptive and accurately diagnose Port


Kennedy [and Florida] Smilodon gracilis." Merriam's (1918) description of
Ischyrosmilus is as follows: "mandible massive, flange clearly marked,
relatively wide anteriorly, slightly wider than in Smilodon, not as strongly
developed as in Machaerodus but shorter than in Smilodon. P3 very small,
with only one root. P4 with single cusp or incipient division of this cusp."
Examination of both the Port Kennedy and Florida sabercat material shows
that they bear little resemblance to Merriam's description. As Churcher
(1984:20) commented, "...the mandibles of S. gracilis and S. mercerii are
more slender and lightly built than are those of S. floridanus ... ." and, as he
adds later, "the flanges...are thinner." Length of the diastema may be of
questionable value as it appears to vary to some degree with the age of the
individual (Merriam and Stock 1932, pl. 4). The reduction in size of P3 is
not diagnostic of Ischyrosmilus, because it is also seen in Smilodon and
Megantereon. Churcher's (1984, Fig. 1) photograph shows that P4 is not
single cusped but rather consists of a principal cusp flanked by a posterior
cusplet and a strong lingual cingulum that forms the tooth heel.
Churcher (1984) compared the Port Kennedy type material of
Smilodon gracilis with the Rancho La Brea and Talara, Ecuador, late
Pleistocene Smilodon and concluded that these sabercats represented
different genera, although he noted their similar morphology and slightly
overlapping measurements. Apart from their smaller size and more gracile
proportions, the most distinctive features of the Port Kennedy sabercat
noted by Churcher include finer serrations on the canine, the absence of a
protocone (despite the presence of a protoradix) on P4, and a well
developed mandibular flange. The condition of the protocone on P4 is
probably variable, as is shown in the larger sample of S. gracilis from both
Inglis IA and Leisey Shell Pit in which a small isolated protocone supported
by a large root is regularly present. The well developed serrations on the
canines and the reduced mandibular flange diagnostic of S. populator are
more reasonably considered species level differences that would be expected
in the transition from S. gracilis to S. populator. In short, Churcher's (1984)
taxonomic proposal does not seem necessary, although his view of
machairodont systematics deserves further testing.
Berta and Galiano (1983) rejected Ischyrosmilus as a useful taxon
and referred the genotype Ischyrosmilus ischyrus to the genus Dinobastis.
The following suite of characters diagnose Dinobastis: mandibular flange
with a strongly rectangular symphyseal margin, angular process long and
bulbous, deeply excavated masseteric fossa, single mental foramen on
flange, and shorter, dagger-like upper canines. This cat is known from
Irvingtonian through Rancholabrean deposits in North America. The
largest, most complete sample is from Friesenhahn Cave in Texas (Meade
1961), although considerable undescribed material from near Fairbanks,
Alaska, exists in the Frick collection (AMNH).


Other recognized species of Ischyrosmilus, I. crusafonti, I. johnsoni,
and I. idahoensis, were reassigned to Homotherium by Berta and Galiano
(1983). Homotherium differs from Dinobastis in the following features:
mandibular flange with an angled symphyseal margin, angular process
prominent but not bulbous, shallow masseteric fossa, and long, strongly
recurved saber-like upper canines. Homotherium is well known in Asia; in
North America it occurs in Blancan sites in California (Asphalto), Idaho
(Fromans Ferry), Texas (Cita Canyon and Channing), and Nebraska
The relationship between Homotherium, Dinobastis, and other
machairodonts was discussed by Berta and Galiano (1983). They
recognized three tribes within the Machairodontinae: Metailurini,
Machairodontini, and Smilodontini. These three tribes share primitively the
following characters: upper canines elongate and laterally compressed,
upper incisors enlarged, P4 parastyle enlarged, P and P /3-4 with strong
anterior and posterior accesory cusps, robust rectangular symphysis, and
reduced coronoid process. Dinobastis, Homotherium, and Machairodus
were included in the Machairodontini. They can be distinguished from
genera in the more derived Smilodontini by the following characters:
deeper more massive mandibles, elongate mastoid process ventrally directed
and not closely appressed to the glenoid process, upper incisors arranged in
a broad arc, shorter flatter upper canines, long narrow carnassials, serrated
margins on P4-M1, M1 with small talonid heel, and long limbs with slender
Smilodon and Megantereon comprise the tribe Smilodontini, sister
group of all other machairodonts. A summary of the cladistic relationships
of Smilodon and related taxa is presented in Figure 19. The close
relationship between Smilodon and Megantereon has been recognized by
various authors (Schaub 1925; Thenius 1967; Kurt6n 1963, 1968; Repenning
1967; Schultz and Martin 1970; Beaumont 1978; and Martin 1980). Martin
(1980) referred S. gracilus (sic) to Megantereon on the basis of the following
similarities: lack of serrations on upper canines, relatively large mandibular
flange, and a large P3. These similarities represent shared primitive
characters and cannot be used to support a close phylogenetic relationship
between these taxa. Berta and Galiano (1983) proposed a closer
relationship of S. gracilis to S. populator than to Megantereon.
Megantereon and Smilodon share the following derived characters
(Fig. 19, point 1): (a) upper canines elongate, laterally compressed, and
recurved; (b) long postcanine diastema; (c) P with reduced protocone,
ectoparastyle enlarged, and anteriorly directed; (d) glenoid process
enlarged; (e) prominent postorbital processes; (f) well developed
supraoccipital crest; (g) lower canines reduced; (h) P2/2 lost; (i) P3/3


Other MachairodonTs Megantereon

S. gracilia S.

Figure 19. Cladogram expressing relationships among the Smilodontini. Numbers
refer to shared derived characters explained in text.

Figure 20. Phylogram expressing relationships among the Smilodontini plotted
against geologic time. Vertical bars represent approximate geochronologic occurrence of a
particular taxon. Lines express relationships. Geologic time scale follows Berggren and
Van Couvering, 1974. Correlation of North American and European mammal ages are
slightly modified from Fejfar (1976) and Repenning (in press).


I ______________ _____


n Villafranchian a
0 C >0

Hemphillian 0'
S o Q

M. inexpectatus



reduced; (j) coronoid process reduced; (k) mandibular flange; (1) limbs and
feet short and stocky; and (m) shortened tail. Smilodon differs from
Megantereon in the following characters (Fig. 19, point 2): (a) incisors
enlarged and procumbent; (b) upper canines further elongated and robust
(c) glenoid process greatly enlarged; (d) mastoid pr cess enlarged; (e) P
reduced, sometimes with single or fused roots; (f) P ectoparastyle further
enlarged; and (g) mandibular flanged reduced.
The Smilodon lineage is comprised of two species. Within this
species group a morphocline is recognized from S. gracilis to S. populator.
S. gracilis can be viewed as a transitional taxon separable from S. populator
largely by its lack of characters. S. populator is distinguished from S. gracilis
on the basis of the following characters (Fig. 19, point 3): (a) larger size; (b)
upper canines more strongly recurved; (c) upper canines and cheek teeth
with strongly serated anterior and posterior margins; (d) P with reduced
protocone; (e) broadened muzzle; (f) mandible with single large mental
foramen; (g) P3 usually absent; and (h) mandibular flange greatly reduced.


Figure 20 summarizes the phylogenetic relationships of Smilodon
and Megantereon plotted against geologic time. The oldest record of
Megantereon is M. hesperus from the late Hemphillian Upper Bone Valley
Formation of Florida (Berta and Galiano 1983). This species ranged into
central and western North America during the middle Blancan. Old World
records of Megantereon indicate that the genus first appeared in Eurasia and
Africa somewhat later, during the early Villafranchian. At least one species,
M. inexpectatus, survived into early Biharian at Choukoutien.
During the late Blancan, the genus Smilodon evolved in North
America. S. gracilis is recorded from the following Florida late Blancan
faunas: Haile XVA (Webb 1974a, Robertson 1976), Santa Fe River IA
(Kurt6n 1965), and Bass Point Waterway No. 1 (Churcher 1984) (Fig. 1).
The age assignment for these faunas is supported by the presence of
Nannippus phlegon (Robertson 1976, MacFadden and Waldrop 1980;
Churcher 1984), a Blancan "index fossil." The El Jobean record of S.
gracilis may also represent a late Blancan occurrence of this taxon.
Unfortunately, no additional fauna was collected from this locality (Burgess,
written communication 1981). S. gracilis is best represented in eastern
North America in the early Irvingtonian of Florida at Inglis IA (Klein 1971,
Webb 1974b), Leisey Shell Pit, and at Port Kennedy Cave, Pennsylvania, the
type locality. The Inglis IA fauna can be considered equivalent in age to the
Curtis Ranch fauna which Lindsay et al. (1975) assigned to the Matuyama
Polarity Chron, approximately 1.9 mybp. In addition to S. gracilis, the


following mammalian taxa are common to both faunas: Chasmaporthetes
ossifragus, Canis edwardii, Platygonus bicalcaratus, Capromeryx arizonensis,
and an advanced Ondatra cf. 0. idahoenis. The Port Kennedy Cave fauna
resembles that of Conard Fissure and Cumberland Cave, which are
probably Kansan in age. A slightly older age, Aftonian or early Kansan, is
suggested for Port Kennedy by the presence of S. gracilis and Ursus
americanus, more advanced than their late Blancan predecessors (Kurt6n
and Anderson 1980). The stage of evolution of Neofiber at McLeod
supports a late Kansan or early Yarmouthian age for the fauna (Frazier
1977). A fragmentary lower jaw here referred to Smilodon cf. S. gracilis was
collected from the late Blancan/early Irvingtonian Palm Springs Formation,
Vallecito Creek, California. The Vallecito section spans an interval from 0.8
to 1.5 mybp and has been correlated with the Blanco and Curtis Ranch
faunas (Kurt6n and Anderson 1980). Kurten (1967) referred a lower jaw
from Rancholabrean deposits as Valsequillo, near Puebla, Mexico, to
Smilodon cf. S. gracilis. However, lack of diagnostic S. gracilis characters;
mandible with large flange, two mental foramina, and a double rooted P,
suggests that this specimen may represent S. populator. According to R.
Graham (pers. comm. 1983), a fragmentary astragalus, atlas, and lumbar
vertebra from this same locality support a less specific identification as
Smilodon sp.
The derived species, Smilodon populator, also apparently evolved in
North America during the late Irvingtonian and extended its range
southward through Mexico and Central America into South America.
Remains of Smilodon (probably S. populator) are documented from
Pleistocene deposits in Chapala and Valle de Puebla, Mexico (Ferrusquia
1979) and Hormiguero, El Salvador (Stirton and Gealey 1943). In South
America, middle and late Pleistocene (Ensenadan-Lujanian) localities
record the presence of S. populator in Argentina, Bolivia, Brazil, Ecuador,
Peru, and Uruguay (Berta 1985). This broad extension in the geographic
range of S. populator is not surprising, especially when one considers the
equally broad present-day ranges of the puma (Felis concolor) in the New
World and the lion (Felis leo) in the Old World. As in North America,
Smilodon became extinct in South America at the end of the Pleistocene.



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Table 1. Measurements of the upper dentition ofSmilodon gracihs.

11 12 13 C P3 P4 M


Port Kennedy PA
ANSP 50 15.4 7.2
ANSP 47 32.0 12.9
ANSP 47 26.8 133
ANSP 47 8.4 4.7
ANSP 46 25.9 13.1
ANSP 44 7.5 5.4 8.7 7.4 103 9.0 35.5 15.2 16.0 6.5 33.7e 11.8e
Inglis IA
UF 18099 16.5e 9.3
UF 12927 14.3e 8.2e
UF 18100 15.9 7.1 30.3 13.3 5.1e 7.5e
UF 12928 14.2e 8.Oe
TRO 1664 31.0 13.2
F:AM 95525 29.7 14.2 16.5 7.8 30.4e 11.5e
F:AM 95526 31.4 14.4e


Table 2. Measurements of mandibular rami of Smilodon gracrls.

Florida Pennsylvania

UF20065 UF18102 UF 18103 UF12931 UF 12941 TRO 1665 ANSP49r ANSP491 ANSP 441

Greatest depth, flangex 528 50 7e 65.0
Least depth ramus
below diastema 264 29.4 26.4e 29.3 303 31.5 31.7e

Depth ramus below MM' 286 28.4 275e 30.1 32.3 324 31.5e
Width ramus at diastema 113 110 11.7e 116 12.0 11.8 13.3
Width ramus at M1 14.5 146 15.9 15 5e 142 16.3 17.3e 15.4e
Mandibular toothrow
length (P3-M1) 49.8 51.9 545 48.6 57.5 57.5 59.3
Height, angle-condyle 29.6

x measured from superior border of symphysis to base of flange; +, measured on the medial side below M1: r right; I, left

Table 3. Mr.iitelllmenils i[ rlie luwce denttiton ot SnulldilOi trrif

11 12 13 C P3 P4 M


Port Kennedy PA
ANSP 44 5.3 3.7 7.1 5.0 8.2 7.5 7.0e 7.3 20.4 9.5 25.2 10.5
ANSP 49 6.3 4.8 7.7 6.2 10.1 7.6 11.5e 43c 203 8.5 22.0 9.8
ANSP 491 6.1 5.0 8.0 5.9 11.2 7.2 10.6e 4.0e 20.2 8.5 22.5 10.0
ANSP 50 20.0 8.4
Inglis IA
UF 18102 11.3e 7.1c 11.0 61 20.3 8.5 23.0 10.0
UF20065 5.6e 3.0e 93e 83e 8.1e 5.3e 18.2 7.8 20.8 9.4
UF 18103 19.0 8.0 20.8 9.7
UF 12933 21.4 7.7
UF 18104 12.0 6.0
TRO 1665 10.1 6.0 18.8 83 20.9 30.0
Santa Fe River IA
FDT 41S 22.2 9.5
F:AM 95522 21.8e 8.9 24.7e 9.7e
F:AM 95527 22.0 9.3
El Jobean
UF 12941 12.0e 4.6e 19.5 8.0 21.3 9.7

r, right; I, lut


Table 4. Comparative measurements of deciduous P4, mandible, and lower dentition of Smilodon gracilis and
S. populator.

S. gracilis, Florida S. populatorl, California

UF 18105a UF 18105b 2002-R-6 2002-R-781

Least depth of ramus
below diastema 19.3 20.6 26.2
Depth ramus below dP4 22.4 12.0 28.2 32.0
Width ramus below dP4 21.8 11.0 15.5 17.4
Greatest depth flange 30.9

S. gracilis

UF 18105a UF 18105c UF 18105d UF 18105b

dP3 AP--- 11.7
T--- 4.8

dP4 AP--- 15.2 14.1 10.1 10.1
T--- 5.2 5.3 4.8 3.6

UF 18101
dP3 AP--- 20.3
T--- 13.7

1 Measurements from Merriam and Stock (1932)


I Ihle 5 Mc.aiurements ot the humerus ot Snuilotr grlacii trom Florida.

Greatest Proximal Proximal Shaft Shaft Distal Distal Least
Length Depth Width Depth' Width' Depth Width Depthx

Inglis IA
UF 18106 237.0 68.5 48.8 36.8 21.7 383 66.6 20.5
UF 18107r 32.6 24.6
UF 181071 31.8 20.7
TRO 1669 32.9 23.0 42.7 70.1 20.6
TRO 1670 74.3 55.3 37.5 24.7 42.3 76.1 21.1
F:AM 95523 41.7 26.3 44.7
F:AM 95528 40.5 25.6

measured at junction of deltoid and pectoral crests; x, measured at middle of trochlea; r, right; I, left.

Table 6. Measurements of the ulnae and radii ot Smilron graclrt from Florida

Ulna Olecranon Olecranon Sigmoid Coronoid
Process Process Notch Process Shaft Shaft Distal
Width Depth Width Width* Width Width" Width

Ingls IA
UF 18109 21.8 33.0 26.5 41.5 42.6 12.7 27.9
F:AM 95524 26.1 31.6 29.7 50.2 47.5 13.8 30.5

Radius Proximal Proximal Distal Distal
Greatest Long Short Shalt Shaft Long Short
Length Diameter Diameter Width* Depth* Diameter Diameter

F:AM 69220 35.2 278 26.4 161 45.6 32.0
F:AM 69219 236 15.4 49.7 313
Inglis IA
UF18108 162 c 28.5 21.2 26.3 12.8

Measured from shIla to coronold process. mai\lmum nl ltcloio oi it dllirmetel
measured ,i h iase of ulnalr tuberusilt
I all:slUred iho\ f 1 rn ;ifrll l o t f 's NClr


Table 7. Measurements ot metacarpals 11. 111, IV. and V ofSmilodon gracilis.

Greatest Proximal Proximal Shaft Shaft Distal Distal
Length Width Depth Width Depth Width Depth

Metacarpal II
Port Kennedy PA
ANSP 51 70.9 15.9 19.5 11.9 11.8 18.7 13.0
ANSP 48 17.5 22.9
Inglis IA
UF 12934 75.0 18.8 22.3 12.0 11.4 17.9 17.2
Haile XVA
UF 17498 74.9 18.8 22.0 13.3 13.0 21.0 18.2
Metacarpal III
Port Kennedy PA
ANSP 48 20.9 20.6
Inglis IA
UF 45409 73.0 17.9 17.5 10.5 10.7 16.7 14.9
Metacarpal IV
Inglis IA
UF 12938 76.4 16.2 18.0 10.9 10.2 15.6 14.7
UF 18110 77.5 16.7 19.4 10.7 10.2 16.8 16.8
F:AM 69249 83.7 19.4 20.6 11.8 11.8 20.1 18.0
Metacarpal V
Inglis IA
UF 12935 58.9 16.3 17.3 9.7 9.7 15.9 14.0


Table 8. Measurements of the temur and tibiae ot Snmlodon gracilis from Florida.

Greatest Proximal Proximal Shaft Shaft Distal Distal
Length Width Depth Width* Depth* Width Depth

Inglis IA
UF 18112 67.4 38.0 31.7 28.4
Haile XVA
UF 17496 22.6 20.2 41.9e 29.4
F:AM 95529 20.8 33.0 44.3 32.8

+, femur measured at base of lesser trochanter; tibia measured at middle of shaft

Iable 9. Measurements ot the astragall ot Smilodon gracils.

Head, Head, Neck,
Greatest Transverse Anteroposterior Transverse
Length Width Diameter Diameter Diameter

Port Kennedy PA
ANSP 48 42.4 37.9 24.7 17.8 19.7
Inglis IA
UF 17496 41.8 37.0 25.6 17.4 20.2
TRO 1666 39.5 36.2 24.3 16.4e 17.0e
TRO 1667 37.6 40.4 23.0 15.2 18.0
F:AM 108536 46.7 41.1 28.2 18.9 20.7


Table 10. Measurements of the calcanei of Smilodon gracilis from Florida

Greatest Distal Sustentacular
Length Width+ Widthx Facet*

Inglis IA
UF 18113 68.4 31.3 20.9 21.7
UF 2399 66.1 31.3 27.6 23.0
UF 24000 69.0 30.7 22.8 24.5
UF 12936 72.9 32.9 30.2 26.0
UF 12937 60.1e 25.4e
TRO 1668 65.6 29.7 253 22.2
F:AM 95534 72.2 37.5 30.8 77.7
F:AM 95532 71.5 38.4 33.6 24.0
F:AM 95333 78.5 36.2 34.9 24.6

+, greatest width across astragalar facets
x, greatest width across cuboid surface
*, least depth of sustentacular facet, measured normal to distal
margin and to edge of facet

Table 11. Measurements of metatarsal III. IV, and V of Smilodon gracilis from Florida.

Greatest Proximal Proximal Shaft Shaft Distal Distal
Length Width Depth Width Depth Width Depth

Metatarsal HII
Inglis IA
UF 12939 84.2 21.1 25.7 13.7 12.0 19.1 15.5
F:AM 69241 90.7 22.2e 283 14.1 12.7 203 17.6
Metatarsal IV
Inglis IA
UF 12940 89.5 17.6 21.8 11.2 12.3 16.3 15.5
F:AM 69243 91.6 20.3 24.7 13.4 14.5 18.0 16.8
F:AM 95530 11.6 12.5 17.9 16.0
Metatarsal V
F:AM 95531 79.4 23.7 18.5 9.9 11.7 15.0 15.9


Table 12. Measurements of proximal and middle phalanges of Smilodon gracilis
from McLeod in Florida.

Proximal Proximal Distal
Length Width Depth Width

Proximal Phalanges
F:AM 95535a 38.2 16.6 17.5 13.8
F:AM 95535b 42.3 19.2 19.7 14.5
F:AM 95535c 40.5 18.0 15.0 13.9
Middle Phalanges
F:AM 108357a 32.5 15.5 13.6 14.0
F:AM 108357b 35.9 15.8 13.1 14.2
F:AM 108357c 34.9 15.2 13.0 16.0
F:AM 108357d 30.2 15.0 12.9 13.7


Table 13. Measurements (mm) and statistics for Smilodon gracilis, S. populator,
and Megantereon cultridens.

Tooth Dimension N X+SE OR CV

Smilodon gracilis
Early Irvingtonia


Late Irvingtonian



S. populator1
Late Irvingtonian



AP 1
T 1
AP 6
T 6

AP 5
T 5
AP 3
T 3
AP 4
T 4

1 31.3
1 13.8

AP 2 28.3
T 2 13.8

Megantereon cultri
Early Villafranchi

Late Villafranchia



AP 8
T 8
AP 8
T 8
AP 4
T 4
AP 5
T 5
AP 3
T 3
AP 10
T 9



1 measurements from Churcher 1984
Late Irvingtonian: Conard Fissure
2 measurements from Kurt6n and Crusafont-Pairo 1977
Early Villafranchian: Perrier, St. Vallier, Puebla
de Valverde
Late Villafranchian: Seneze, Olivola, Valdarno



9.4- 9.7

6.5- 7.8


6.2- 7.4
8.7- 9.7

6.3- 8.5


Table 14. Fore- and hindfoot measurements (mm) and statistics for Smilodon gracihs, S. populator, and Megantereon

Element Dimension N X+SE OR CV

Smilodon gracilis
Early Irvlngtonian
Metacarpal II



Metatarsal IV

Late Irvingtonian
Metacarpal II



Metatarsal IV

S. populator1
Late Irvingtonlan
Metacarpal II



Metatarsal IV

Megantereon white 2
Late Villafranchlan
Metacarpal II



Metatarsal IV

Length 2
Width 2
Length 5
Width 6
Length 3
Width 3
Length 1
Width 1

Length 1
Width 1
Length 3
Width 3
Length 2
Width 2
Length 1
Width 1

Width 1
Length 1
Width 1
Length 3
Width 3
Width 1

Length 1
Length 1
Length 1
Width 1











measurements from Churcher 1984
Late Irvingtonian: Conard Fissure
" measurements from Vrba 1981

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