BULLETIN of the FLORIDA STATE MUSEUM Biological Sciences Volume 31 1987 Number 1 THESABERCAT SMILODON GRACILIS FROM FLORIDA AND A DISCUSSION OF ITS RELATIONSHIPS (MAMMALIA, FELIDAE, SMILODONTINI) ANNALISA BERTA e UNIVERSITY OF FLORIDA GAINESVILLE Numbers of the BULLErIN OF THE FLORIDA STATE MUSEUM, BIOLOGICAL SCI- ENCES, are published at irregular intervals. Volumes contain about 300 pages and are not necessarily completed in any one calendar year. OLIVER L. AUSI'IN, JR., Editor S. DAVID WEBB, Assotiate Editor RHODA J. BRYANT, Managing Editor Consultants for this issue: WILLIAM A. AKERSI'EN ROBERT HUNT, JR. 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 THE SABERCAT SMILODON GRACILIS FROM FLORIDA AND A DISCUSSION OF ITS RELATIONSHIPS (MAMMALIA, FELIDAE, SMILODONTINI) ANNALISA BERTA* ABSTRACT 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. fracilis from Florida are similar to the type material from Port Kennedy Cave, Pennsylvania. Smilodon Eracilis is most closely related to S. Dopulator 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; uITer canines and cheek teeth with very finely serrated anterior and poster* margins; P with a well developed protocone; mandible with a large flange, two mental foramina, and a double-rooted P); less robust limbs and elongate hindfeet. Smilodon shares a sister group relationship with Megantereon. S. gracilis is more derived than Mezantereon in having incisors enlarged and procumbent, upper canines elongate and robust, P4 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. Eracilis) 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, Gainesville. BERTA, A. 1987. The sabercat Smilodon gracilis from Florida and a discussion of its relationships (Mammalia, Felidae, Smilodontini). Bull. Florida State Mus., Biol. Sci. 31(1):1-63. 2 BULL. FLORIDA SrATE MUSEUM, BIOL SCI. VOL. 31(1) 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. RESUMEN Se describen las dentaduras y extremidades del tigre dientes de sable, Smilodon Eracilis, provenientes de variosas localidades en Florida. Las edades varian entre el Blancano tardio y el Irvingtoniano. Estas muestras constituyen los registros mas numerosos y mejor conocidoi 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 entre el Irvingtoniano tardio y el Rancholabreano, tanto en Norte como Sur Amdrica. El tigre dientes de sable es mas primitivo que S. populator, ya que presenta los caninos superiores s610 ligeramente curvados, lo~ caninos superiores y molares carecen deI margen anterior y posterior poco serrado; el P tiene el protocono bien desarrollado; la mandibula tiene un reborde grande; dos for menes y un 2 de doble raiz; extremidades menos robustas y patas traseras elongadas. Smilodon tambi6n esta relacionado al g6nero Mezantereon. S. Rracilis es mas avanzado que Megantereon porque tiene incisivos alargados y procumbentes; caninos superiores alargados y robustos; el ectoparaestilo de P4 bien desarrollado; y los procesos mastoideo y glenoideo alargados. Smilodon iracilis muestra una tendencia al aumento de tamafio a trav65 del tiempo. La morfologia de las extremidades y proporciones generales 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 11anuras y bosques abiertos. De acuerdo a su dentadura altamenta especializada y fuerte, las extremeidades y patas corta, Smilodon desarrol16 tdcnicas de captura de presad en base al asalto y emboscada, en vez de persecuci6n rdpida. BERTA: SMILODON GRACILIS FROM FLORIDA 3 TABLE OF CONTENTS INTRODUCHON 3 ACKNOWLEDGEMENT'q 4 ABBREVIATIONS........................................................................................................................... 5 TAXONOMIC HISTORY OF Smilodon..................................................................................... 8 SYSTEMATIC PALEONTOLOGY............................................................................................. 12 Holotype ....................'......................-- -..e............~......'.................. -.......*-.........-.................... 1 Type bcality 12 Revised Distribution and Age 12 Emended Diagnosiq 12 Referred Specimens...................................................................................................................... 13 DESCRIPTION OF FLORIDA MATERIAL........................................................................... 14 Postcranial Skeleton...................................................................................................................... 20 ADAPTATIONS: 39 SIZE TRENDR 43 PHYLOGENETIC RELATIONSHIPq 43 GEOGRAPHIC AND SrRATIGRAPHIC DISrRIBUTION 48 LITERATURE CITFn 40 TART Rt 54 INTRODUCTION 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 smilod6ntine cats. The sabertooth "tiger," Smilodon flon'danus, 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 4 BULL. FLORIDA SI'ATE MUSEUM, BIOL. SCI. VOL. 31(1) 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 gmcilis, is less well known. Dental and postcranial remainsare 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 gmcilis is considerabiy smaller than S. populator and more slenderly built. The sabers are enlarged but lack strongly serrated e~ges. A distinct protocone and enlarged ectoparastyle are present on P . 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. ACKNOWLEDGEMENTS 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. MadFadden, 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. BERTA: SMILODON GRACILIS FROM FLORIDA 5 ABBREVIATIONS 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, Fricl~: 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. LOCALITIES 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 POIN'r 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. 6 BULL. FLORIDA STATE MUSEUM, BIOL. SCI. VOL. 31(1) A ectoparastyle posterior cingulumparac e parastylemetastyle posterior cusplet para- -1-1metacoq% p ---- rincipal cusp 7 metacone protocone/ protocone or,terior cusplet 8 posterior cingulumanterior cingulpm protoconid / principal cuspparaconid ~ 1 ~nterior cusple, -rincipal cusp 1 talonid posterior cusplet Mi 1~ 5 9 1 2 ? 4 5cm 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. BERTA: SMILODON GRACILIS FROM FLORIDA 7 1 2 SANTA FE RIVER 0 1-3 O HAILE XVA 0 Mc LEOD K INGLIS I A 0_20_100'150 Kilometers BASS PT WATERWAY 0 EL JOBEAN 7 0 Figure 2. Smilodon gracilis localities in Florida. 8 BULL. FLORIDA SrATE MUSEUM, BIOL. SCI. VOL. 31(1) MCLEOD:-A fissure fill deposit, McI£od 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.). TAXONOMIC HISTORY OF SMILODON 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 Kurttn and Anderson (1980). The oldest name for a North American Smilodon is Felis (Trucifelis) fatalis proposed by Leidy (~868) 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 7>uctfelis fatalis. Although Merriam and Stock (1932) and Simpson (1945) recognized Tmcifelis 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." floridanus. Beginning with Bovard (1907) all later workers have referred this species to Smilodon. Bovard (1907) proposed the species S. cal(fomicus for the excellent sample from Rancho La Brea, California. He distinguished this species from S. flon'danus by its shorter muzzle, more posterior position of the postefior nares, and ridges BERTA: SMILODON GRACILIS FROM FLORIDA 9 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. flon'danus was the orientation of the mastoid process. Slaughter's (1963) analysis of Smilodon supported the condusion previously developed by Lammers (1959) that S. cahfomicus Bovard is a synonym of S. flortdanus Leidy. Kurten's (1965) study of Florida Smilodon led him to synonymize S. jbidanus with S. fatalis and to maintain S. cal®micus as distinct. He distinguished S. cal®micus on the basis of its larger size, broader mastoid region, and "presence of an accessory cuspule on M1·" 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. cal(fomicus with S. floridanus. A recent study of North and South American sabercats proposed synonymy of S. ,#oridanus 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 yld cheek teeth with strongly serrated anterior and posterior margins, P with very reduced or absent protocone, mandible with reduced flange, single foramen, and 5 usually absent. 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, SmUodontopsis troglo*tes 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. cal(fomicus; 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 anteroposterlor 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 individuai variation seen in S. populator (Berta 1985). Size criteria are not of primary importance in recognition of Smilodon species. As Slaughter noted, all S. famlis 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 SmUodon 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 10 BULL. FLORIDA SrATE MUSEUM,.BIOL. SCI. VOL. 31(1) dimorphism, because those specimens that exhibit narrow, triangular occiputs also possess well developed sagittal crests. Slaughter's diagram showing the relati6nship between the lower canine and P< is plotted in Figure 3 with the addition of North and South American miadle 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. famlis (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 large5t specimens of S. populator are from late Pleistocene (Ranchoiabrean 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. Tko 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" inerpecmta (Gay Vostreys, written communication 1979). Among a large number of postcranial elements catalogued under S. mercem as ANSP 51, only a proximal right metatarsal II and a left metacarpal II are referable to SmUodon. In a third paper Cope (1899) assigned "U " mercen'i 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 "b." mercen'i 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. BERTA: SMILODON GRACILIS FROM FLORIDA ' 11 18- 0 • . 17- ....0 16- • 0 0 0 ell. 015- Tr an sv er se D ia m et er P 4 A P Di am et er C . . ... 0 .dt .1 , 0 14- ..6 . . .. 0.. 13- . 00 . 0 .. O/ O/ 12- d 11- 10- 22 23 24 25 26 27 28 29 30 AP Diameter P4 15_ 14- 0 0 .13. .0% ... 0 0 12 -,0 00 :.. ' 0 "% 00 Fdooo . 11- 0 6 c~'. . 10.i 1 , , 1d o 20 21 22 23 24 25 26 27 28 29 30 AP Diameter P4 Figure 3. Comparative dental measurements of Smilodon populator (North American sample; Merriam and Stock 1932 and additional specimens) (0 Rancholabrean), Smilodon fatalis (Leidy 1868) (I= Rancholabrean, dtrvingtonian), and Smilodon populator (South American sample; Berta 1985) (0= Lujanian, d= Ensenadan). 12 BULL FLORIDA STATE MUSEUM, BIOL. SCI. VOL. 31(1) SYSTEMATIC PALEONTOLOGY ORDER CARNIVORA BOWDICH 1821 SUBORDER FELIFORMIA KREIZOI 1945 SUPERFAMILY FELOIDEA SIMPSON 1931 FAMILY FELIDAE GRAY 1821 SUBFAMILY MACHAIRODONTINAE GILL 1872 TRIBE SMILODONTINI KUR'IN 1963 GENUS SmUodon 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 mercen'i Cope 1899:245, pl. XX, fig. 2 Smilodon (Smilodontopsis) gmcilis Merriam and Stock 1932:15 Smilodontopsis (Machaerodus) gracilis Brown 1908:190 Smilodontopsis (Machaerodus) mercerli Brown 1908: 190 Machaerodus7 mercen7 Matthew 1918:229 Machaerodus, gracUis Matthew 1918:229 Machaerodus gracilis Matthew 1918:229 Machaerodus gracilis Slaughter 1960:490 Machaerodus mercerit 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, Pennsylvania. REVISED DISRIBUTION AND AGE.--Late Blancan-Late Irvingtonian of Pennsylvania and Florida. EMENDED DIAGNOSIS.--Differs from Smilodon populator in having upper canines only slightly recurved; uppfr canine teeth with very finely serrated anterior and posterior margins; P with well developed protocone; mandible with large flange, two mental foramina, double-rooted Pq; less robust limbs and elongate hindfeet. Differs from Old and New World species of Megantereon in having incisors enlarged and procumbent; upper BERTA: SMILODON GRACILIS FROM FLORIDA 13 canines elongate and robust; P4 ectoparastyle well developed; and mastoid and glenoid processes enlarged. REFERRED SPECIMENS.--PORT KENNEDY CAVE, PENNSYLVANIA: ANSP 44, crushed and distorted facial region of skull lacking right Ml (crown of left upper canine broken and mandible missing right C); ANSP 45, right All in ranyl fragment; ANSP 46, left upper canine; ANSP 47, right and left P , left M , left jaw fragment; ANSP 48, right astragalus, proximal ends of metacarpals II and III, ungualfhalanx; ANSP 49, right and left rami ' missing Il, 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,t /d-.-- BY,'J/~ C ---/ 4\L 4 4>d#1'1* / I 4©\ 11111'lle Fil 4 \ 111 Mil M i h i a'' C , f i $2. .-Y.:~B:-<45 "~(,0.,t,i«»~82 h411 \ u g Figure 7. Right humuus, UF 18106, of Florida Smilodon gracilis from Inglis IA. (A) proximal; (B) posterior; (CD lateral views. (a) bicipital groove, (b) lesser tuberosity, (c) olecranon fossa, (d) greater tuberosity, (e) for insertion of M. teres minor, (0 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 hi. infraspinatus. BERTA: SMILODON GRACILIS FROM FLORIDA 23 (Schaub 1925), while in true cats these surfaces form an arcuate connection. The depression for insertion of M. injtaspinatus is at the same level as the head of $he 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. tens 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. crtensor carpi radialis and atensor communis digitomm. Below this elongate facet is a small, short area of origin for the M. ectensor digitomm 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. 88), Among these cats, the high, strongly developed lateral margin affords a broader area of insertion for the lateral head of the M. tn'ceps 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 24 BULL. FLORIDA SrATE MUSEUM, BIOL. SCI. VOL. 31(1) 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. BA). 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 poUicis 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. fleror digitomm projitndus. 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 BERTA: SMILODON GRACILIS FROM FLORIDA 25 A Ba \0,\1"i/7,7112 \" 1,111 , ' 4, :lr 1 *1 .41 lip , 0 1,/(-b-/1 4 S.' % .:4, -C- 0 '' % 11 . 111 11 1 1 4 0 1 2 3 4 5cm / 1 1/lilli 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. 26 BULL. FLORIDA STATE MUSEUM, BIOL. SCI. VOL. 31(1) A B S.:,f, i,~Ilf ~l~j jiff' '8//75 h- C' i 'i lill\\\ ; 1~ 1111*n g- i 11! ' dd 441 1,~lt' _f#lia 1 Iff )1111 1, .4\''h * fill ~t f-h «111 1 Ii' Si 4 'll '11 I f+'til lic 1\\ 41\\hd'111'11/'Ni\\\\\ti' "t ''h\\ /7,)4.11.In//j'/ 1411'41<){,0)'A -j ed 9 1 9 9 4 fcm Figure 9. Left radius, F:AM 69220, of Smilodon gracilis from McLeod. (A) anterior; (ED posterior views. (a) for insertion of M. supinator; (b) for origin of M. abductor pollicis Iongus, (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 dipitorum profundus. (j) styloid process. BERTA: SMILODON GRACILIS FROM FLORIDA 27 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 unciform, 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 ca,pi mdialis which is responsible for flexion of the wrist. In lateral view, the crescentic facet for the unciform 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. 1OB). 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 unciform facet. Measurements for F:AM 108538 are as follows: anteroposterior diameter, 34.8; transverse diameter, 44.7; proximodistal diameter, 25.7. Ab B g 4, t »Il mil,~ 11111 da-f#» f,11\ 'jj)} -m»-r TE©: 'F' ,".7 -I:~,V e 10,9?lim 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 unciform, (g) for articulation with trapezoid. 28 BULL. FLORIDA STATEE MUSEUM, BIOL. SCI. VOL. 31(1) 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. ertensor calpi 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 trapeziumwas noted by Vrba (1981) in ~ Megantereon whitei 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 charactefistic of the genus. A facet for the magnum is lacking. A left metacarpal III, UF 45409, is known from Inglis IA (Fig. 11(, D, Table 7). The proximal surface which articulates with the magnum is broadly concave. Along its lateral border is a rectangular facet for the unciform. 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. atror and F. onca. In medial view, the anterior facet for metacarpal I[ 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. llE, 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. llE), a diagnostic feature of this genus is apparent. The unciform 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 BERTA: SMILODON GRACILIS FROM FLORIDA 29 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. 116, H, Table 7). The rounded proximal surface which articulates with the unciform 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. edensor calpi ulnans which functions to extend and abduct the forepaw. In medial view (Fig. 11H), the notch which incises the margin of the articulating facet f6r 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 6f attachment for extensors of the hip, the Mm. gluteus, medius, minimus, and pynfonnis. 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. vasms extemus, an extensor of the hip joint. - A right patella, F:AM 108538, is represented from McI«eod (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. 30 BULL FLORIDA STATE MUSEUM, BIOI- SCI. VOL. 31(1) ABCDr\* # 7 h8)-3- X./, AF -:IAd (t -fir,~ v-,,~) 'j ' ~/ tf i~'~ \6 -4# 11~ IN-If ~ , b/. St 1 ij Ili~|It;~d, j, 4.56 ,4~ Y*Z)'il'J 3--I-= jj EFGH i k m 0 \\\ X,+ 9- -j \11\r n -1 Nu '' , 1 -111 1 d 1 1, _s/ 1-) *a, 0]2g45cm1 11 , rf -<-r=B a B -_,/11 I \ /1 D 6 N #MA ' ./ r, 1,))1 4/f , III 4 , 1 r #-2144. ~. 1,4 ii,jd d l I \\ 0 ] 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 Rracilis from McLeod. (C) posterior; (D) lateral views. Figure 11. Right metacarpal II, UF 17498, of Florida Smilodon gracilis from Haile XVA. (A) anterior; (13) 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, (0 for origin of M. interosseous, (g) for articulation with unciform, (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 unciform, 0) 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 unciform, (n) for insertion of M. extensor carvi UInaris, (o) for articulation with metacarpal IV. 32 BULL. FLORIDA ST'ATE MUSEUM, BIOL. SCI. VOL. 31(1) A right and a left distal tibia, UF 17496 and F:AM 95529, are represented from Haile XVA and McLeod (Fjg. 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 culmdens 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. flecor haUucis 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 McI«eod (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 cultnWens. 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. #*is, 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 BERTA: SMILODON GRACILIS FROM FLORIDA 33 joined. In S. gracilis and F. onca, a narrow articular strip connects these facets. The large, concave astragalocalcanear facet in SmHodon 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, A ~ B» C 69 >. 11, 0,1 I'll (* 9\. f' " # 11 1 \11 11 j* f 14 1j'11 f 4 lilli 41 r / 1