238

J. Paleont., 83(2), 2009, pp. 238–262Copyright � 2009, The Paleontological Society0022-3360/09/0083-238$03.00

CRANIAL MORPHOLOGY AND SYSTEMATICS OF AN EXTRAORDINARYSAMPLE OF THE LATE NEOGENE DWARF TAPIR,

TAPIRUS POLKENSIS (OLSEN)RICHARD C. HULBERT JR.,1 STEVEN C. WALLACE,2 WALTER E. KLIPPEL,3 AND PAUL W. PARMALEE4

1Florida Museum of Natural History, University of Florida, Gainesville 32611-7800, �rhulbert@flmnh.ufl.edu�; 2Don Sundquist Center of Excellence inPaleontology, Department of Geosciences, East Tennessee State University, Box 70357, Johnson City 37614, �wallaces@etsu.edu�;

3Department of Anthropology, University of Tennessee, Knoxville 37996; and 4Frank H. McClung Museum, University of Tennessee, Knoxville 37996

ABSTRACT—The previously poorly known ‘‘Tapiravus’’ polkensis Olsen, 1960 (Mammalia, Perissodactyla, Tapiridae) isnow known from abundant, well preserved specimens from both the type area in central Florida and from the Gray FossilSite (GFS) in eastern Tennessee. The latter has produced over 75 individuals, the greatest number of tapirids from asingle fossil site, including many articulated skeletons. Almost all linear measurements taken on skulls, mandibles, andcheek teeth from GFS have coefficients of variation less than 10 (most between 3 and 7), indicating the presence of asingle species. However, the sample reveals considerable intraspecific variation for a few key morphologic features,including development of the sagittal crest, outline shape of the nasals, and number and relative strength of lingual cuspson the P1. The Florida sample of T. polkensis is more limited, but has the same state as the GFS sample for all preservedcharacters of systematic significance, and while the Florida teeth are on average smaller (especially narrower lower cheekteeth), they fall either within or just below the observed range of the Gray Fossil Site population. The new materialsupports a reassignment of ‘‘Tapiravus’’ polkensis to the genus Tapirus, and demonstrates that the geologic age of thespecies is significantly younger than previously thought, Hemphillian rather than Barstovian. Tapirus polkensis is thesmallest known North American Tapirus, and smaller than any of the extant species in the genus, with an estimatedaverage mass of 125 kg.

INTRODUCTION

WHEN OLSEN (1960) proposed the species name Tapiravuspolkensis, it was the only formally described fossil tapir

of middle Miocene to early Pliocene age in North America. It wasbased on just three specimens from Florida, one isolated uppertooth and two partial mandibles, all lacking stratigraphic prove-nance. Because of these limitations, the phylogenetic affiliationand chronologic range of ‘‘T.’’ polkensis have remained enig-matic. The general consensus has been that it was a relativelylarge species of the poorly understood genus Tapiravus Marsh,1877 from the middle Miocene (e.g., Schultz et al., 1975; Schoch,1984; Colbert and Schoch, 1998).

Beginning in the middle 1960s, S. D. Webb of the Universityof Florida and his students began a long-term project to betterunderstand the biostratigraphy, morphology, and systematics ofthe vertebrate fossils produced as a by-product of phosphate min-ing in south-central Florida (Fig. 1). All previously describedspecimens from this region, including the tapirs described by Ol-sen (1960), lacked precise locality and stratigraphic provenance.There had been considerable previous debate about whether thefossil vertebrates found in the phosphate mines consisted of oneor two faunas, and how this fauna (or faunas) correlated withthose from the central and western United States and Europe. Thediscovery and collection of in situ faunal assemblages by UF andTRO paleontologists, some found in stratigraphic superposition,resulted in a much more complex biostratigraphy for the CentralFlorida Phosphate District (CFPD) than previously realized, withthree major intervals of vertebrate fossil accumulation in the Mio-cene and Pliocene (the Bradley, Agricola, and Palmetto faunas ofWebb and Hulbert, 1986), as well as more limited and localizeddeposition at other times. This field work and generous donationsby amateur collectors gradually built up the sample of tapirs fromthe CFPD, including for the first time specimens collected in di-rect association with biochronologically useful species of equids,camelids, proboscideans, and carnivores (Webb et al., 2008).However, the taphonomic nature of the CFPD deposits resultedin the recovery of only relatively durable elements of the skeleton,primarily partial mandibles, isolated teeth, the ends of limb bones,and complete bones of the manus and pes. While much more

adequate than the sparse sample available to Olsen (1960), nev-ertheless many of the cranial bones valuable in tapirid systemat-ics, such as the lacrimal, nasal, frontal, and parietal, have neverbeen recovered in the CFPD.

In 2000, a highway construction project near the town of Gray,Washington County, Tennessee, exposed highly fossiliferous Neo-gene sediments, now referred to as the Gray Fossil Site (GFS),which cover an area of about 2.5 hectares and are up to 40 metersthick (Figs. 1, 2; Parmalee et al., 2002; Wallace and Wang, 2004;Shunk et al., 2006). The recovered fossil assemblage includesboth large and small mammals, as well as fish, amphibians, rep-tiles, birds, invertebrates, and botanical material (Wallace andWang, 2004; Table 1). Recovery of the rhino Teleoceras Hatcher,1894 and the short-faced bear Plionarctos Frick, 1926 restrict theage of the sediments to between 4.5 and 7 Ma (late Miocene toearly Pliocene, Hemphillian Land Mammal Age; Tedford et al.,2004). Although some fossils were lost before construction workcould be halted, state geologists and archaeologists convinced theTennessee Department of Transportation (TDOT) to move thehighway, and the GFS was eventually transferred to the jurisdic-tion of East Tennessee State University (ETSU). In addition,ETSU was awarded a TDOT Enhancement Grant to build the EastTennessee State University and General Shale Brick Museum ofNatural History adjacent to the site (Fig. 2.1), which opened inAugust of 2007, to permanently house the specimens collected atthe GFS since the fall of 2001, and to provide public exhibits andinterpretation of the finds. Specimens collected in 2000 and early2001 are housed in the UTK collection.

The GFS is significant because it is the only pre-PleistoceneCenozoic vertebrate fossil locality in the Appalachian region ofthe eastern United States (altitude is �500 m), and it preserves abiota (including vertebrates, invertebrates, plant macrofossils andpollen) quite unlike any other in North America (Wallace andWang, 2004; DeSantis and Wallace, 2008). Among its unusualaspects is that tapirs are the most commonly recovered large ver-tebrate, representing about 90% of the large mammals and witha current minimum number of individuals exceeding 75. As faras we have been able to determine, this is the greatest number offossil tapirs ever recovered at a single locality, and this number

239HULBERT JR. ET AL.—LATE NEOGENE DWARF TAPIR

FIGURE 1—Map of the eastern United States showing the locations of the Gray Fossil Site and the Central Florida Phosphate District.

will increase significantly, as much of the site remains to be ex-cavated. The GFS tapir differs in size and morphology from allother described species from North or South America with theexception of ‘‘Tapiravus’’ polkensis from Florida. With the refer-ral of the GFS population to ‘‘T.’’ polkensis, the taxon goes frombeing an enigmatic species to one of the best known fossil mem-bers of the Tapiridae.

The purpose of this paper is to provide a detailed descriptionof the cranial and dental morphology of ‘‘Tapiravus’’ polkensisfrom the CFPD and GFS, to compare this species with others inNorth and South America, Asia, and Europe, and to provide ev-idence that it belongs in the genus Tapirus Brunnich, 1771 insteadof Tapiravus. This is one of several planned descriptive paperson North American Tapirus (see also Hulbert, 2005). Upon theircompletion, we will conduct a detailed phylogenetic analysis todetermine the evolutionary relationships of North American andextant Tapirus. Description of the postcranial elements of the GFStapir and their ecologic implications will be the subject of anotherstudy. Stable isotope paleoecology of the GFS tapir was discussedby DeSantis and Wallace (2008).

GEOLOGY AND TAPHONOMY OF THE GRAY FOSSIL SITE

Geologic analyses of the fossil-bearing units indicate that theyformed within a sinkhole, which filled to become a pond or smalllake (Shunk et al., 2006), resulting in the deposition of typical

lacustrine sediments (finely laminated, organic rich, silty claysand sands). Early in its formation, the sinkhole may have actedas a natural trap (Wallace et al., 2002). However, as the depressionfilled with water and sediment (including the remains of the localbiota), the site went through a second phase when it served as awater hole/pond (as indicated by fish, amphibians, turtles, alli-gators, and large mammals). While numerous, the accumulationof remains was attritional, rather than due to any catastrophicevent. The great abundance of tapirs relative to any other taxon,in addition to the fairly equal representation of the various ageclasses, suggests that the tapirs were living in the former pondand surrounding forest, while the presence of other taxa was moretransitory and therefore they were less likely to be incorporatedwithin the deposit (DeSantis and Wallace, 2008). Moreover, therapid infilling of the basin during both phases of its history re-sulted in the preservation of many articulated or nearly articulatedskeletons (Fig. 2.2). Although large amounts of overburden havebeen removed as a result of the earth-moving activities associatedwith the road project, merely the later stages of deposition arenow exposed at the surface. Consequently, the early history ofthe site will be exposed for analysis only through many years ofsystematic and detailed excavation.

MATERIALS AND METHODS

All measurements are reported in millimeters. Comparativesamples are the same as listed in Hulbert (2005). Boundaries and

240 JOURNAL OF PALEONTOLOGY, V. 83, NO. 2, 2009

FIGURE 2—1, aerial view of Gray Fossil Site (GFS) and adjacent museum (as shown, under construction in early 2007), Washington County, Tennessee.North is towards the bottom of the figure. 2, semi-articulated skeleton of Tapirus polkensis being excavated at the GFS. Bottom block contains virtuallycomplete right and left hind limbs plus two vertebrae. To the top are additional vertebrae of this individual. This type of preservation is common at the GFS.Scale bar equals 10 cm.

subdivisions of late Neogene North American land mammal agesfollow Tedford et al. (2004). Terminology of crests and ridges onthe dorsal surface of the skull follow Holbrook (2002). The genusTapirus is defined as all species of Tapiridae sharing a closer

common ancestry with the type species of the genus, Tapirusterrestris (Linnaeus, 1758), than with the type species of othervalid genera in the Tapiridae as defined and used by Colbert(2005).

241HULBERT JR. ET AL.—LATE NEOGENE DWARF TAPIR

TABLE 1—Vertebrate fauna of the Gray Fossil Site, Washington County, Ten-nessee. Compiled from Parmalee et al. (2002), Wallace and Wang (2004),and Schubert and Wallace (2006). Much of the fauna remains unstudied orunpublished; identifications are made to the lowest taxonomic level possibleat this time.

OsteichthyesSeveral spp.

AmphibiaAnura

Rana sp.Several spp. in other genera

CaudataAmbystomatidae

Ambystoma sp.Plethodontidae

ReptiliaTestudines

Sternotherus sp.Chelydra serpentina (Linnaeus, 1758)Chrysemys sp.Terrapene sp.Trachemys sp.Hesperotestudo sp.

CrocodyliaAlligator sp.

SquamataColubridae

NatricinaeColubrinae

ViperidaeAves

Several spp.Mammalia

XenarthraMegalonychidae

InsectivoraSoricidae

minimum 3 spp. presentTalpidae

minimum 2 spp. presentChiropteraLagomorpha

LeporidaeRodentia

minimum 6 spp. presentProboscidea

GomphotheriidaePerissodactyla

Equidaecf. Cormohipparion sp.

TapiridaeTapirus polkensis (Olsen, 1960)

RhinocerotidaeTeleoceras cf. T. hicksi Cook, 1927

ArtiodactylaTayassuidae

cf. Prosthennops sp.indeterminate gen. and sp.

Camelidaecf. Megatylopus sp.

Carnivoraindeterminate medium-sized sp.

Felidaecf. Machairodus sp.

UrsidaePlionarctos sp.

MustelidaeArctomeles dimolodontus Wallace and Wang, 2004one additional sp.

AiluridaePristinailurus bristoli Wallace and Wang, 2004

Institutional abbreviationsETMNH, East Tennessee State University and General Shale

Brick Museum of Natural History, Gray; LACM, Natural HistoryMuseum of Los Angeles County; MCZ, Museum of ComparativeZoology, Harvard University, Cambridge; TRO, Timberlane Re-search Organization, Lake Wales, Florida (J. S. Waldrop and as-sociates); UF, Florida Museum of Natural History, Gainesville;

UF/FGS, collection of the Florida Geological Survey, nowhoused at the Florida Museum of Natural History; UF/TRO, col-lection of the TRO, now housed at the Florida Museum of NaturalHistory; UNSM, University of Nebraska State Museum, Lincoln;USNM, U.S. National Museum, Smithsonian Institution, Wash-ington, D.C.; UTK, McClung Museum, University of Tennessee,Knoxville; YPM, Peabody Museum, Yale University, New Ha-ven, Connecticut.

Morphological abbreviations

IOF, infraorbital foramen; L, greatest length; DL, postcaninediastema length; HT, height; AW, greatest anterior width mea-sured across the protoloph or protolophid near the base of thecrown; PW, greatest posterior width measured across the metal-oph or hypolophid; W, width; i, lower incisor; I, upper incisor;c, lower canine; C, upper canine; m, lower molar; M, upper mo-lar; p, lower premolar; P, upper premolar (a numeral following atooth abbreviation indicates a specific tooth locus; e.g., m2 is asecond lower molar). A d or D in front of a tooth abbreviationindicates a deciduous tooth (e.g., DP1).

Statistical abbreviations

x, sample mean; s, sample standard deviation; OR, observedrange of a sample; N, sample size; CV, sample coefficient ofvariation.

Chronologic and geographic abbreviations

CFPD, Central Florida Phosphate District (�Bone Valley; Fig.1); Cl, Clarendonian land mammal age; GFS, Gray Fossil Site,Washington County, Tennessee (Fig. 1); Hh, Hemphillian landmammal age; Ma, meganna, millions of years before present.

Ontogenetic descriptors

The following phrases are used to designate seven general on-togenetic life history stages in Tapirus based on tooth eruptionand wear. Their temporal durations are not equal, but their usewill allow comparisons between ontogenetically equivalent indi-viduals.

• Very young juvenile: DP1–DP3 and dp2–dp3 with little orno wear are the only fully erupted cheek teeth; DP4 and dp4may be erupting.

• Young juvenile: DP1–DP4 and dp2–dp4 are all fully erupted;M1 and m1 may be erupting; teeth slightly worn.

• Juvenile: DP1–M1 and dp2–m1 are all fully erupted and inwear. Adult premolars and second molars fully formed incrypts.

• Subadult: P1–P3, DP4, M1 and p2–p3, dp4, m1 are fullyerupted and in wear; M2 and m2 may be erupting; little orno wear on P1–P3 and p2–p3, heavy wear on DP4 and dp4.

• Young Adult: P4, M2, p4 and m2 have erupted and are inwear; M3 and m3 either erupting or fully erupted, but withlittle or no wear.

• Full Adult: Lophs of M3 and m3 moderately worn, but noexposed dentine.

• Old Adult: Lophs of M3 and m3 have exposed dentine be-cause of heavy wear.

SYSTEMATIC PALEONTOLOGY

Order PERISSODACTYLA Owen, 1848Family TAPIRIDAE Burnett, 1830Genus TAPIRUS Brunnich, 1771

TAPIRUS POLKENSIS (Olsen, 1960)

Tapiravus (?) sp. WHITE, 1942, p. 91Tapiravus polkensis OLSEN, 1960, p. 164, fig. 1; SCHOCH, 1984,

p. 5; COLBERT AND SCHOCH, 1998, p. 577; WALLACE AND

WANG, 2004, p. 557.

242 JOURNAL OF PALEONTOLOGY, V. 83, NO. 2, 2009

Tapirus polkensis (Olsen, 1960) HULBERT, 1999, p. 53A; HUL-BERT, MACFADDEN, AND WALDROP, 2001, p. 297, fig. 14.29;WALLACE AND HULBERT, 2005, p. 127A; HULBERT, 2005, p.490–491, fig. 13D–I; WEBB, HULBERT, MORGAN, AND EVANS,2008, p. 302–303, fig. 6A.

non Tapiravus cf. T. polkensis Olsen, 1960. WEBB AND TESSMAN,1968, p. 805; SCHULTZ, MARTIN, AND CORNER, 1975, p. 4–6.

Holotype.⎯UF/FGS 5941, left P3.Type locality.⎯Phosphate mine of the American Agricultural

Chemical Company in Polk County, Florida. Exact locality andstratigraphic level unknown, almost certainly Palmetto Fauna ofUpper Bone Valley Formation (see below).

Occurrence.⎯Late Miocene and earliest Pliocene (Hh2 andHh4, using terminology of Tedford et al., 2004) of peninsularFlorida (Hulbert, 2005); Hemphillian of eastern Tennessee.

Referred CFPD specimens.⎯CFPD, specific locality unknown:UF/FGS 5942, subadult mandible with left c and m2 (in crypt)and right p2–m1 (paratype); MCZ 3808, juvenile mandible withdp4–m1; UF 223989, full adult mandible with m1–m3 (cast). Pal-metto Mine, Polk County: UF/TRO 1537, P2; UF 14447, p4; UF177740, m1. District Grade Mine, Polk County: UF 204872, fulladult mandible with p2–m3 (cast). Tiger Bay Mine, Polk County:UF/TRO 1390, old adult maxilla with P4–M3. Fort Green Mine,Polk County: UF 223986, young adult mandible with p2–p4(cast); UF 223988 old adult mandible with p4–m2 (cast); UF223987, full adult mandible with m1–m3 (cast). Fort Green Mine,Hardee County: UF 224871, partial mandible with roots of m3.Fort Green Mine, Manatee County: UF 220250, DP4; UF 232100,M1. Gardinier Fort Meade Mine, Polk County: UF 223794, ju-venile mandible with dp2–m1 (cast); UF 220447, supraoccipital.Achan Mine, Polk County: UF 14445, old adult mandible withm1–m3. Kingsford Mine, Polk County: UF 133911, mandibularsymphysis with c.

Referred GFS specimens.⎯Very young juveniles: ETMNH610; 693; 695; 3677; 3678; 3679; 3680; 3681; 3682; 3683; 3690;3696; 3697; 3718; 3806; UTK 30.1 Young juveniles: ETMNH605; 685; 3684; 3685; 3686; 3687; 3688; 3689; 3691; 3692; 3794;3804; 4059; 4099; 5334; UTK 31.1; 41.1. Juveniles: ETMNH481; 600; 604; 684; 3693; 3694; 3698; 3720; UTK 21.4. Sub-adults: ETMNH 611; 3695; 3699; 3700; 3701; 3702; UTK 29.1;100.1. Young adults: ETMNH 291; 602; 646; 651; 681; 3426;3703; 3704; 3705; 3706; 3719; 3843; 5327; UTK 21.1; 21.3; 22.2;25.1; 23.1; 28.1. Full adults: ETMNH 595; 608; 680; 682; 687;3425; 3427; 3707; 3708; 3709; 3710; 3711; 3712; UTK 17.4;24.1; 28.2; 33.1; 36.1. Old Adults: ETMNH 606; 607; 683; 688;3519; 3573; 3713; 3714; 3715; 3716; 3717; 3992; 5326. Onlylisted are mandibles, maxillae, skulls, and skeletons with associ-ated cranial material; hundreds of additional postcranial elementsand isolated teeth are also known from the GFS.

Revised diagnosis.⎯Smallest North American species of Tap-irus, with linear skeletal and dental dimensions on average 15–20% smaller than Tapirus terrestris and an estimated averagemass of 125 kg. Skull has narrow lacrimal bone with broad, flat-tened posterior process; extensive but shallow meatal fossa ondorsal surface of frontal and nasal bones with well defined pos-terior and medial margins; dorsal table of frontal broad, flat, notswollen, and on same plane as nasals; low parasagittal ridges orsagittal crest; and large, triangular interparietal bone that fuseswith supraoccipital in the subadult stage. Mandible has mentalforamen located ventral to p2, vertically oriented ascending ra-mus, and short postcanine diastema. P1 highly variable in bothrelative width and development of lingual cusps; the majority ofspecimens have a single lingual cusp and lack a transverse loph.Protoloph of P2 relatively weak, ends low on ectoloph near par-astyle. Upper premolars relatively broad; P3–M3 with tall, wellseparated protolophs and metalophs and large parastyles. Poster-olabial cingula common on upper cheek teeth. Lower first incisor

larger than i2; i2 much larger than i3. Lower premolars with com-plete hypolophids.

DESCRIPTION OF TAPIRUS POLKENSIS (OLSEN)

Skull.⎯Cranial measurements are listed in Table 2. Unless oth-erwise noted, features described here are those present in subadultor adult individuals. The rostrum is narrow with a relatively shortpostcanine diastema (Fig. 3; Table 2). In lateral view, the posteriorprocess of the premaxilla terminates in an acute point at a leveleither immediately anterior to the P1 (e.g., ETMNH 682, 3699,3700, 3716, UTK 23.2) or dorsal to the P1 (e.g., ETMNH 602,608, 3519, UTK 21.1, 21.3, 24.1; Fig. 4). The medial process ofthe maxilla extends anteriorly 25 to 37 mm medial to the posteriorprocess of the premaxilla and is visible in lateral view to a varyingdegree (Fig. 4). A faint, low vertical flange is generally presenton the dorsal edge of the anteromedial process of the maxilla.This flange is less than 3 mm tall, but is present on all but onespecimen preserving this region (N � 14). Posterior to the max-illary flange, the border of the maxilla is thin, projects medially,and is not rolled ventrally. The posterodorsal ascending processof the maxilla forms the margin of the narial aperture back to themiddle of the orbit where it articulates with the descending pro-cess of the nasal; this portion of the maxilla is widely exposeddorsally, not twisted laterally. The anterior supraorbital process ofthe frontal overlaps the lacrimal dorsally and articulates mediallywith the maxilla and descending process of the nasal. The nasalnotch ends at a point dorsal to the middle of the orbit (Fig. 3.2).

Dorsal to the orbit, the frontal forms a broad, concave shelfthat carried the meatal diverticulum (Fig. 5). The meatal fossa onthe dorsal surface of the cranium occupies most of the anteriorportion of the frontals and the posterior half of the nasals. Thisfossa is shallow, has a relatively uniform depth, and has welldefined posterior and medial margins on the frontal and nasal(Fig. 5). The anterior margin of the meatal fossa on the nasal isgenerally less distinct, but shows wide variation. For example, themeatal fossa is relatively faint and more limited on the nasals ofETMNH 600, 3519, 3687, and 3700, while relatively pronouncedand wide on the nasals of ETMNH 605, 607, 611, and 3699. Inall specimens the fossa on the nasals approaches within a fewmillimeters of the midline of the skull. The size of the preservednasals varies, but the lateral edge is posteriorly convex and an-teriorly most often either relatively straight (8 of 18 specimens)or concave (9 of 18 specimens), very rarely convex. Nasal Lexceeds maximum W across the right and left nasals. The nasalsare relatively thin and flat anteroposteriorly with a slight down-ward dip at the rostral end. The posterolateral margin of the nasalis relatively flat or curved slightly downward. The right and leftnasals are separated posteriorly by a 7- to 15-mm-long anteriorprocess of the frontals along the midline (Fig. 5.1). The nasalsand frontals are on the same plane (the dorsal surface of the fron-tals is not raised relative to that of the nasals as in some species;Fig. 3.2).

The dorsal table of the frontals (the region bounded anterolat-erally by the meatal fossae and posterolaterally by the parasagittalridges) is large and very flat, but not markedly inflated. The rightand left frontal-parietal sutures meet at the midline in a posteriorlydirectly point, with the exception of ETMNH 605 in which thissuture is irregularly transverse (Fig. 5.2).

The GFS sample of skulls contains two different morphologiesrelated to the development of the parasagittal ridges (�temporalcrests) and sagittal crest (Figs. 6–7). In the more commonly ob-served condition (found on about 75% of the individuals, N �20), the posteriorly converging parasagittal ridges on the parietalsnever merge to form a true sagittal crest (Fig. 6). Minimum widthacross the parasagittal ridges in general narrows progressivelywith age: 19–29 mm in juveniles, 17.5 mm in a subadult, and13–17 mm in adults. The parasagittal ridges themselves generally

243HULBERT JR. ET AL.—LATE NEOGENE DWARF TAPIRT

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244 JOURNAL OF PALEONTOLOGY, V. 83, NO. 2, 2009

245HULBERT JR. ET AL.—LATE NEOGENE DWARF TAPIR

FIGURE 4—Lateral views of the rostrum of Tapirus polkensis from the GFS. 1, ETMNH 682, left lateral view. Teeth present are left I1–I3, C, and P1–P4.Note enlarged, caniniform I3, reduced C, and presence of maxillary flange; 2, ETMNH 3716, left lateral view with P1–P4. Lac � lacrimal bone.

←

FIGURE 3—Skull of Tapirus polkensis, ETMNH 3719, from the GFS. 1, dorsal view; 2, right lateral view; 3, ventral view of rostrum and palate with rightand left I1–I3, C, P1–M3.

become slightly taller and wider with increasing age, but are rare-ly more than 3 mm taller than the surrounding surface of thecranium. The area inside the parasagittal ridges is generally flatand at the same level as the dorsal tables of the frontals and theinterparietal-supraoccipital. In full and old adults, the parasagittalridges meet briefly at the midline (e.g., ETMNH 606, 607, 3718,3719; Figs. 3.1, 6.3), but a true sagittal crest did not form.

The less common condition, found on skulls belonging to atleast five individuals, is for taller parasagittal ridges in juvenilesand a true sagittal crest in adults (Fig. 7). ETMNH 600, a juvenile,has tall parasagittal ridges that converge strongly and extendalongside each other for about 15 mm before diverging posteriorly(Fig. 7.1), with a minimum width across the crests of only 10.5mm. In UTK 59.1, an isolated braincase that is judged to be from

246 JOURNAL OF PALEONTOLOGY, V. 83, NO. 2, 2009

FIGURE 5—Dorsal surface of skulls of Tapirus polkensis from the GFS detailing features of the nasal and frontal bones. Anterior to left. 1, ETMNH 3519;2, ETMNH 605. Note broad meatal fossa with sharp posterior and medial margins in both specimens. ant. proc. frontal � anterior process of frontals.

247HULBERT JR. ET AL.—LATE NEOGENE DWARF TAPIR

FIGURE 6—1–3, Dorsal surface of skulls of Tapirus polkensis from the GFS detailing features of the frontal, parietal, interparietal, and supraoccipital bonesand ontogenetic variation in development of the parasagittal ridges. Anterior to top. 1, ETMNH 3699, subadult; 2, ETMNH 3705, young adult; 3, ETMNH3717, old adult. This morphotype, with low parasagittal ridges that do not unite to form a sagittal crest, is present in about 75% of the GFS skulls (juvenileversion of this morphotype shown in Fig. 5.2). 4, UF 220447 from the CFPD, isolated supraoccipital in dorsal view; arrows point to unfused suture withinterparietal. IP � interparietal; paras. ridge � parasagittal ridge.

FIGURE 7—Dorsal surface of skulls of Tapirus polkensis from the GFS detailing features of the frontal, parietal, interparietal, and supraoccipital bones.Anterior to top. 1, ETMNH 600, juvenile; 2, UTK 59.5, subadult(?); 3, ETMNH 3843, young adult; 4, ETMNH 3519, old adult. This morphotype, with tallparasagittal ridges in juveniles that unite to form a sagittal crest in adults, is present in about 25% of the GFS skulls. FR � frontal; IP � interparietal; PA� parietal; pr � parasagittal ridge; sc � sagittal crest.

a subadult based on the relative degree of closure of sutures, thetall, strongly converging ridges merge at the frontal-parietal sutureto form a flat sagittal table (Fig. 7.2) and extend together for about30 mm before diverging posteriorly. Minimum width across thesagittal table is 9.0 mm. In a young adult, ETMNH 3843, theparasagittal ridges are compressed and form a double-lined sag-ittal crest that extends for about 32 mm (Fig. 7.3). Two old adults,

ETMNH 3519 and 3573, have fully formed sagittal crests. InETMNH 3519, it extends for about 27 mm with a minimum widthof 5.3 mm and height of 7.3 mm (Fig. 7.4).

The parasagittal ridges diverge posterolaterally forming the an-terolateral edges of a flat, triangular-shaped region. Most of thisflattened region originally ossified as a single, large interparietalbone. With one exception (ETMNH 605), the overall shape of the

248 JOURNAL OF PALEONTOLOGY, V. 83, NO. 2, 2009

FIGURE 8—Posterolateral views of skulls of Tapirus polkensis from theGFS showing lacrimal foramina. 1, ETMNH 600 in right lateral view, with asingle large lacrimal foramen (more common morphotype); 2, ETMNH 3687in left lateral view (reversed), with two lacrimal foramina (rarer morphotype).

interparietal is triangular, although its margins are rarely straight(Figs. 6, 7). The interparietal of ETMNH 605 has a generallyrectangular to oval shape. Interparietal width ranges between 23.5and 31.5 mm and anteroposterior length between 16 and 34 mm(N � 7); in most individuals width is 5–20% greater than length.The interparietal is not fused with either of the surrounding skullbones (occipital or parietals) in juveniles (e.g., ETMNH 600, 605,3691, 3718). The interparietal-supraoccipital suture is beginningto close in the subadult ETMNH 3699 and is completely closedin most full and old adults (e.g., ETMNH 607, 3519, 3704; anexception is ETMNH 683). The suture between the parietals andoccipital-interparietal does not close until the old adult stage. Theparasagittal ridges are continuous with the lambdoidal crestswhich are relatively thin and project mostly posteriorly with slightlateral flair (Figs. 6, 7). The posterior surface of the occipital,between the lambdoidal crests and dorsal to the foramen magnum,is moderately slanted anterodorsally-posteroventrally.

In lateral view, the descending premaxillary-maxillary sutureintersects the alveolar margin just anterior to the alveolus for theC. The infraorbital foramen is located dorsal to the P3; its pos-terior margin is formed by a 7- to 9-mm-wide strut of the maxilla(Fig. 4). The lacrimal bone articulates anteriorly with this max-illary strut, dorsally with the frontal, and ventrally with the jugal.Dorsoventral HT of the lacrimal greatly exceeds anteroposteriorL, and its lateral surface is generally smooth and slightly concave(more rarely moderately concave, e.g., UTK 17.4). The dorsal andanterior portions of the lacrimal’s lateral surface become increas-ing rugose with age. An anterior lacrimal process is usually lack-ing, but if present (e.g., ETMNH 608 and 3573, UTK 17.4 and21.3) is merely a slight rugosity. The posterior lacrimal processis broad and flat, and its size varies greatly. Eleven of 14 indi-viduals in which the posterior portion of the lacrimal is preservedhave a single, large lacrimal foramen that is not visible in lateralview (Fig. 8.1). In UTK 17.4, ETMNH 611, and 3687, a smallstrut of bone extends medially from the posterior process creatingtwo openings on the orbital margin of the lacrimal (Fig. 8.2).However, these foramina open into a common chamber whichthen rostrally penetrates the lacrimal as a single foramen as in theother individuals.

The medial wall of the orbit is best preserved in ETMNH 600.The sphenopalatine foramen is centrally located, relatively large,and placed dorsal to the much smaller posterior palatine. Theposterior medial wall of the orbit bears several sharp ridges, most-ly on the area formed by the frontal. In this region two smallforamina lie close to each other: the optic foramen directly dorsalto the anterior lacerate foramen. The anterior opening of the ali-sphenoid canal lies posteroventral to the anterior lacerate foramen,and is hidden from lateral view by a strong ridge in ETMNH 600.

The postglenoid and mastoid processes converge slightly, anddo not contact one another, leaving the external auditory meatusopen ventrally (Fig. 3.2). The relatively narrow and slender distalend of the paroccipital process projects 15 to 20 mm beyond theend of the mastoid process in a posteromedial direction. The me-dial surface of the mastoid and paroccipital processes is highlyrugose for muscle attachment.

In ventral view, the incisive foramen begins just posterior tothe I3 and ends anterior to or level with the P1 (Fig. 3.3). Theanterior margin of the internal choanae is at the level of the M2protocone. The zygomatic process of the maxilla ends posteriorlyat the level of the middle of the M3. The postglenoid process istall and compressed, extending posterolaterally at about a 50 de-gree angle to the long axis of the skull. There is no separatepostglenoid foramen, and the foramen ovale is confluent with themiddle lacerate foramen. The petrosal is broadly visible in ventralview inside a large foramen bounded medially by the basisphe-noid, anteriorly by the alisphenoid and postglenoid region of the

squamosal, and posteriorly by the mastoid process of the squa-mosal and the basioccipital. The basisphenoid and anterior pro-cess of the basioccipital are relatively narrow. The hypoglossalforamen is oval, about 5 mm wide by 3.5 mm long, and visiblein ventral view. It is closer to the posterior margin of the lacerateforamen than to the occipital condyle. The medial margins of theventral surfaces of the right and left occipital condyles are widelyseparated, with a minimum distance between them of 14–19 mm

249HULBERT JR. ET AL.—LATE NEOGENE DWARF TAPIR

FIGURE 9—Adult mandibles of Tapirus polkensis from the GFS (1–4) and CFPD (5–6). 1, ETMNH 682 in right lateral view; 2, ETMNH 3719 in rightlateral view; 3, ETMNH 682, dorsal view of symphysis and anterior dentition; 4, ETMNH 3719 in right medial view (reversed); 5, UF 223986 in right lateralview; 6, UF 14445 in right medial view (reversed). Arrows in 2 and 5 indicate location of mental foramen ventral to p2. All scale bars equal 5 cm.

(21–29% of occipital condyle W). The foramen magnum is rel-atively large and oval, with its W about a third greater than HT(W, x � 28.5, N � 6; HT, x � 21.7, N � 4).

Mandible.⎯In lateral view, the ventral border of the ramus isflat to slightly convex posterior to the uplifted symphysis (Fig.9.1). The angle is inflected medially and the mandibular fossa isrelatively large, shallow, and with pronounced ridges that beginat the posterior margin (Fig. 9.4, 9.6). The mandibular foramenis located at the same height as or slightly dorsal to the crownsof the molars. Mandibular condyle height is moderate (46%) rel-ative to overall length (Table 3). The anterior margin of the as-cending ramus projects vertically and slightly posteriorly in lateralview (Fig. 9.1, 9.2), so that at the level of the condyle it does notoverlie the posterior part of the m3. The masseteric fossa is largeand deep, with a ventral border located at about the level of thecrowns of the molars. The medial surface of the horizontal ramusis generally flat, although ventral to the molars is a distinct con-cave groove for the origin of the mylohyoideus. The short sym-physis (Table 3) has a deeply concave dorsal surface. The mental

foramen is about 20–25 mm below the alveolar margin, and di-rectly ventral to the p2 (Fig. 9).

Dentition.⎯The overall morphology of the incisors and caninesis similar to that of other North American Tapirus, in particularthe greatly reduced C and i3, the large, caniniform I3, and en-larged, spatulate i1 (Figs. 3.3, 4.1, 9.3). There are no diastematabetween either the upper or lower incisors, nor between the i3and c. I2 and I3 orientation is strongly opisthodont; I1 is slightlyopisthodont to orthodont. The I3 and C are separated by a dia-stema of 3.5 to 5 mm. The I3 is on average about 10% largerthan the c (I3 L, x � 10.0, s � 0.85, N � 15; I3 W, x � 9.3, s� 0.78, N � 15; c L, x � 9.2, s � 0.54, N � 12; c W, x � 8.2,s � 0.66, N � 12 [GFS sample only]) and, with CVs less than9, neither tooth displays pronounced sexual dimorphism. Meso-distal L of the C is on average 56% of I3 L (N � 6), and C Wis 51% of I3 W (N � 6). The i2 is significantly smaller than thei1 and both have a procumbent orientation in the symphysis (Fig.9.1–9.3). The di2 is only slightly smaller than the di1 and both

250 JOURNAL OF PALEONTOLOGY, V. 83, NO. 2, 2009

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251HULBERT JR. ET AL.—LATE NEOGENE DWARF TAPIR

TABLE 4— Standard statistics for upper premolars and molars from the GFS sample of Tapirus polkensis (ETMNH and UTK collections) and measurementsfor three specimens from the Central Florida Phosphate District (CFPD), including the holotype, UF/FGS 5941.

T. polkensis GFS

N x s Min. Max. CV

T. polkensis CFPD

Catalogue No.

P1 L 30 14.39 0.92 12.3 16.5 6.42P1 W 30 13.25 1.21 11.5 16.2 9.12P2 L 35 15.39 0.67 14.0 17.0 4.37 UF/TRO 1537 14.7P2 AW 36 16.78 0.97 15.1 19.1 5.80 UF/TRO 1537 15.1P2 PW 35 18.98 0.72 17.8 20.8 3.80 UF/TRO 1537 18.3P3 L 38 16.09 0.64 14.5 17.0 3.98 UF/FGS 5941 17.0P3 AW 35 20.36 1.00 16.6 22.0 4.90 UF/FGS 5941 20.4P3 PW 36 20.04 0.75 18.5 21.9 3.72 UF/FGS 5941 20.1P4 L 37 16.78 0.77 15.0 18.3 4.57 UF/TRO 1390 17.0P4 AW 36 21.74 1.11 19.4 23.4 5.13 UF/TRO 1390 21.6P4 PW 36 20.57 1.03 19.0 22.6 4.99 UF/TRO 1390 20.8M1 L 50 17.94 0.98 15.4 20.1 5.45 UF/TRO 1390 17.6M1 AW 51 20.96 0.89 19.4 22.9 4.25 UF/TRO 1390 22.1M1 PW 49 18.30 0.79 16.7 20.0 4.34 UF/TRO 1390 20.2M2 L 41 19.78 0.93 17.9 21.7 4.71 UF/TRO 1390 19.7M2 AW 42 22.84 0.70 21.4 24.1 3.07 UF/TRO 1390 23.8M2 PW 42 19.70 0.84 17.4 21.3 4.27 UF/TRO 1390 21.1M3 L 37 20.19 0.91 18.8 23.4 4.52 UF/TRO 1390 20.2M3 AW 38 22.65 0.78 21.4 24.2 3.44 UF/TRO 1390 22.3M3 PW 37 18.36 0.94 16.1 20.5 5.10 UF/TRO 1390 17.9

are much smaller in size, and are not as spatulate as the corre-sponding permanent teeth (ETMNH 605). The deciduous incisorsand canines are replaced during the juvenile stage (e.g., ETMNH605 retains deciduous incisors while ETMNH 600 and 3693 haveerupted but unworn permanent incisors and canines).

The W of the P1 is on average 92% of L (Figs. 10, 11; Table4), but P1 W is the most variable dental parameter (CV � 9.1).The ratio P1 W/L therefore ranges widely between 81 and 103%.The morphology of the P1 is best observed on subadults andyoung adults that have little or no wear (N � 9). The labialportion of the crown is united in a sharp ectoloph; the paraconeand metacone are situated close to each other; and the paraconeis the taller, more bulbous cusp although neither it nor the meta-cone extend much beyond the level of the remainder of the ec-toloph. Development of the lingual cusp(s) shows considerablevariation (Fig. 11). Three of the nine individuals have a single,relatively small and low lingual cusp located opposite the meta-cone (ETMNH 602, 3426, and 3701; Fig. 11.1). Three individuals(UTK 29.1, ETMNH 3699, 3843) also have a single lingual cusp,but it is larger and taller than in the preceding three (Fig. 11.4).The P1 of UTK 21.1 and ETMNH 3700 have a very small cuspulelocated directly anterior to a large posterior lingual cusp (Fig.11.2), while the P1 of ETMNH 611 has two distinct, large lingualcusps, although the posterior one is twice the size of the anteriorcusp (Fig. 11.3). Half the individuals lack a transverse loph ex-tending from the lingual cusp towards the ectoloph, while theother half have a very slight fold that extends labially from thelingual cusp towards the metacone (Fig. 11). A low cingulumextends along the anterolingual side of the P1, and terminates atthe anteriormost point of the tooth. With wear, the P1 ectolophremains a sharp ridge, while the lingual cusp wears flat (e.g.,ETMNH 682).

The AW of the P2 is 81–95% of PW, with an average value of88% (N � 35; Figs. 10, 11; Table 4). The P2 metacone andparacone are well separated, unlike those of the P1, but in theunworn state also barely project beyond the level of the rest ofthe ectoloph. The P2 has a small parastyle and low anterior andposterior cingula. A few specimens have a posterolabial cingulum,but the frequency of its presence is less than in the succeedingteeth. The transverse lophs are oriented obliquely, especially theweak protoloph that extends from the protocone towards the para-style where it connects near the base of the ectoloph. The metal-oph is oriented more transversely than the protoloph, and is taller,uniting about halfway along the height of the ectoloph (Fig. 11.2–

11.4). As in the succeeding teeth, the metaloph curves posteriorlyjust prior to uniting with the metaloph, so that it connects withthe metacone.

The P3 is more molariform than the P2 with AW approximatelyequally to PW (Figs. 10, 11; Table 4), a taller protoloph that uniteswith the paracone instead of the parastyle, protoloph and metal-oph oriented transversely, a larger parastyle, and a more widelyseparated protocone and hypocone. The P4 continues these trends,basically being a larger version of the P3 with taller cusps andlophs, and AW is almost always greater than PW (OR of P4 AW/PW is 97–111%, x � 106; N � 35). The P2-P4 are relativelybroad (ratio of W to L) compared to most other tapirs. The M1through M3 have moderate to large parastyles that are separatedfrom the paracones by deep creases (Fig. 10). The M1 is on av-erage 8–10% smaller than the M2, but the two are otherwisesimilar in morphology and proportions. The M2 and M3 havevery similar L and AW, but M3 PW is on average 7% less thanthat of the M2. The labial side of the metacone bears a distinctcingulum in about two-thirds of the P3–M3.

The DP1 is slightly smaller than the P1 (Tables 4, 5), lowercrowned, and has thinner enamel, better developed posterior andanterolingual cingula, and greater separation between the para-cone and metacone on the ectoloph (Fig. 12.1). Unlike the P1,the DP1 has a strong transverse loph extending labially from themain lingual cusp. This loph decreases in height labially, but con-nects low on the ectoloph just anterior to the metacone. The DP2is about equal in length as the P2, but is much narrower (Table5) and has a much lower crown. The more widely separated pro-tocone and hypocone on the DP2 give it a somewhat more mo-lariform appearance than the P2, although the AW is still lessthan PW and the protoloph connects with the parastyle rather thanthe paracone (Fig. 12.1). The DP2 protoloph is weaker and moreobliquely oriented than the metaloph and the parastyle is smalland low. The DP3 and, to an even greater degree, the DP4 aremorphologically and proportionally more like lower-crowned mo-lars than their permanent successors, with PW less than AW (Ta-ble 5; Figs. 11.3, 12.1). The average for the ratio DP4 AW/PWis 114.2 (N � 26), which is nearly identical to the same ratio inthe M1 (114.7, N � 49). However, compared to the M1, the DP4is relatively narrower (Fig. 12.1; DP4 mean AW/L � 109.7 vs.117.1 for the M1). The crown height and enamel thickness of theDP4 are greater than those of the DP3, as would be expected ina tooth that remains functional for a longer period of time. The

252 JOURNAL OF PALEONTOLOGY, V. 83, NO. 2, 2009

FIGURE 10—Upper cheek teeth of Tapirus polkensis from the GFS (1–2) and CFPD (3–4) shown in occlusal view. 1, ETMNH 3699, left (reversed) maxillawith P1–P3, DP4, M1–M2; 2, ETMNH 3843, right maxilla with P1–M3; 3, UF/TRO 1390, partial right maxilla with P4–M3; 4, UF 232100, right M1.

frequency of posterolabial cingula on the DP2–DP4 is similar tothat of the permanent teeth.

The lower cheek teeth have the classic bilophodont morphologyof Tapirus (Figs. 12.2, 12.3, 13; Tables 5, 6). The premolars havecomplete hypolophids whose unworn height is slightly less than

that of the protolophids. The unworn protolophid and hypolophidare of equal height on molars. The p2 protoconid is located closeto and more anterior than the metaconid and these two cuspsmerge with wear. A tall metalophid extends anteriorly from thep2 hypoconid, blocking the transverse valley, and then curves

253HULBERT JR. ET AL.—LATE NEOGENE DWARF TAPIR

FIGURE 11—Upper premolars of Tapirus polkensis from the GFS (1–4) and CFPD (5) shown in occlusal view. 1, ETMNH 3426, left (reversed) maxillawith C and P1; 2, ETMNH 3700, left (reversed) P1–P3, DP4; 3, ETMNH 611, right P1–P3; 4, ETMNH 3699, right P1–P3; 5, UF/FGS 5941, left (reversed)P3, holotype.

TABLE 5— Standard statistics for deciduous premolars of Tapirus polkensisfrom the Gray Fossil Site (GFS).

N x s Min. Max. CV

DP1 L 22 14.15 0.70 13.0 15.3 4.97DP1 W 22 12.95 0.75 11.7 14.5 5.82DP2 L 35 15.97 0.84 14.8 17.7 5.28DP2 AW 33 14.46 0.88 12.9 15.9 6.06DP2 PW 34 15.85 0.80 14.5 17.9 5.05DP3 L 37 16.67 0.71 15.1 18.2 4.24DP3 AW 36 16.87 0.85 15.3 18.8 5.07DP3 PW 36 16.49 0.79 14.8 18.0 4.79DP4 L 26 17.73 0.68 16.6 19.1 3.84DP4 AW 26 19.43 0.90 17.8 21.5 4.63DP4 PW 26 17.02 0.82 15.8 19.3 4.82dp2 L 18 19.56 0.64 18.6 21.1 3.29dp2 PW 20 11.35 0.56 10.4 12.5 4.89dp3 L 25 17.57 0.74 16.0 18.9 4.23dp3 AW 23 11.46 0.58 10.4 12.6 5.08dp3 PW 23 11.77 0.63 10.6 12.9 5.39dp4 L 20 18.70 0.77 16.9 19.9 4.14dp4 AW 19 12.83 0.44 11.9 13.7 3.41dp4 PW 18 12.44 0.66 11.2 14.0 5.33

lingually just before uniting with the protolophid. A similarlycurved paralophid originates from the protoconid and extends tothe anteriormost point of the p2. A fainter third ridge extendsfrom the protoconid, projecting anterolingually and gradually de-creasing in height as it reaches the lingual side of the p2. Averagep2L/p3L is 109% (N � 20, OR � 102–122). The p3 is narrowerand shorter than the p4, and its AW is greater relative to PW(Table 6; Fig. 13). The p3 metalophid is moderately well devel-oped, but less than that of the p2, but greater than on the p4 ormolars where it is just a slight ridge that does not obstruct thetransverse valley. Prominent anterior and posterior cingulids arepresent on unworn and slightly worn p3–m3, but they are oblit-erated by interdental wear (except the posterior cingulid on them3). The posterior cingulid of the m3 lacks a prominent hypo-conulid, but has a very small stylid or slight rise on the centralportion of the cingulid (Fig. 13). There are no lingual or labialcingulids. As was the case with the upper molars, the m1 is onaverage about 10% smaller than the m2, but proportionally similar(Table 6). On m1 and m2, PW is on average about 4–6% lessthan AW, but m3 PW averages 10% less than AW.

The dp2 has the same general morphology as the p2, but is onaverage 15% longer and of similar width, so is proportionallynarrower (Fig. 12.2, Table 5). The dp2 hypolophid is completeand as tall as the protolophid. In addition to the protolophid andparalophid, two other ridges emanate from the dp2 protoconid:

254 JOURNAL OF PALEONTOLOGY, V. 83, NO. 2, 2009

FIGURE 12—Juvenile cheek teeth of Tapirus polkensis from the GFS (1–2) and CFPD (3) shown in occlusal view. 1, ETMNH 3720, left (reversed) maxillawith DP1–DP4, M1; 2, ETMNH 3692, right mandible with dp2–dp4; 3, UF 223794, right mandible with dp2–dp4, m1.

the anterolingually directed ridge as observed on the p2, and ashort but prominent ridge that extends posterolabially for 2 to 3mm just labial to the metalophid. The dp3 and dp4 are relativelynarrow, have weak anterior and posterior cingulids, and have low-er AW/PW ratios than the m1–m2, but are otherwise molariform(Table 5; Fig. 12.2, 12.3). Unlike the p3, the dp3 lacks a strongmetalophid, such that it has a widely open transverse valley. Asmall but distinct metastylid is present on the posterolingual sideof the metaconid on the dp2–dp4.

DISCUSSION

Questions regarding the original hypodigm.⎯Olsen (1960)identified the holotype, UF/FGS 5941, as a P4. Yarnell (1980)determined that UF/FGS 5941 could just as easily be a P3 as aP4. Evidence in favor of it being a P3 include the relative small

differences in PW and AW (Table 4), the slightly oblique (anter-olabial-posterolingual) orientation of the protoloph and metalophrelative to the ectoloph, and the lack of a concavity on the lingualmargin between the protocone and hypocone (Fig. 11.5). How-ever, the high ratio of W to L favors identification as a P4. Dis-criminant function analyses on known P3s and P4s from the re-ferred GFS sample determined that UF/FGS 5941 is most likelya P3 (Wallace and Hulbert, 2005; Wallace et al., in prep.). Therelatively low, poorly separated transverse lophs on UF/FGS5941, which have been used as characteristics favoring its genericassociation with Tapiravus, are the result of wear.

A misleading portion of Olsen’s (1960) original description ofUF/FGS 5941 was his listing of its ‘‘greatest transverse diameter’’as 22 mm. To obtain this value, Olsen (1960) measured an almostdiagonal dimension between the posterolabial and anterolingual

255HULBERT JR. ET AL.—LATE NEOGENE DWARF TAPIR

FIGURE 13—Lower cheek teeth of Tapirus polkensis from the GFS (1–4) and CFPD (5–6) shown in occlusal view. 1, ETMNH 3699, right mandible withp2–p3, dp4, m1–m2; 2, ETMNH 3719, right mandible with p2–m3; 3, ETMNH 608, right mandible with p2–m3; 4, ETMNH 3717, right mandible with p2–m3; 5, UF 223986, partial right mandible with p2–p4; 6, UF 14445, partial right mandible with m1–m3.

TABLE 6—Standard statistics for lower premolars and molars of Tapirus polkensis from the Gray Fossil Site (GFS) and Central Florida Phosphate District(CFPD) samples.

T. polkensis GFS

N x s Min. Max. CV

T. polkensis CFPD

N x s Min. Max. CV

p2 L 29 17.98 0.80 16.9 19.9 4.46 2 17.05 0.21 16.9 17.2 1.24p2 PW 30 11.89 0.76 10.7 13.4 6.41 3 11.37 0.67 10.8 12.1 5.86p3 L 34 16.40 0.96 14.4 18.2 5.86 3 16.60 0.53 16.0 17.0 3.19p3 AW 32 12.24 0.62 10.7 13.8 5.07 3 11.17 0.28 10.9 11.5 2.47p3 PW 35 13.81 0.78 11.7 15.3 5.68 3 12.99 0.46 12.6 13.5 3.57p4 L 40 17.16 0.86 15.3 18.9 4.99 4 16.90 0.63 16.4 17.7 3.75p4 AW 39 14.09 0.73 12.2 15.5 5.20 5 13.05 0.59 12.4 13.9 4.51p4 PW 40 14.82 0.96 12.5 17.9 6.49 4 14.23 0.53 13.5 14.8 3.75m1 L 39 18.17 1.00 16.2 21.0 5.53 8 17.43 0.95 15.4 18.4 5.47m1 AW 40 14.02 0.59 12.6 15.3 4.24 8 13.10 0.40 12.2 13.5 3.07m1 PW 40 13.19 0.66 11.9 15.1 5.01 8 12.44 0.70 10.8 13.1 5.65m2 L 33 20.40 0.85 18.9 22.0 4.16 6 19.40 0.64 18.6 20.2 3.31m2 AW 32 15.13 0.59 13.7 16.2 3.89 6 14.02 0.50 13.4 14.6 3.57m2 PW 33 14.58 0.64 13.2 16.2 4.36 6 13.60 0.48 12.9 14.3 3.51m3 L 27 21.32 1.21 19.7 24.7 5.68 4 19.66 0.24 19.5 20.0 1.20m3 AW 27 15.37 0.54 14.3 16.5 3.52 4 14.08 0.32 13.6 14.3 2.27m3 PW 26 13.99 0.67 12.6 15.2 4.77 4 12.93 0.46 12.4 13.4 3.54

corners of the crown (this is the only way to obtain a W of 22mm on this specimen), a method that produces a larger value thanstandard widths (see Table 4). Thus, Olsen’s (1960) W for UF/FGS 5941 can not be directly compared to values reported bySimpson (1945), Schultz et al. (1975), Ray and Sanders (1984),Hulbert (1995, 2005) or most other papers on fossil tapirids.

Olsen (1960, p. 165) listed the type locality of T. polkensis asa ‘‘. . . phosphate pit of American Agricultural Chemical Com-pany, Pierce, Polk County, Florida.’’ No collector nor collectiondate is listed on the original UF/FGS catalogue record. This com-pany operated several mines in the CFPD in the late 1940s and1950s, including the Carmichael, Boyette, and South Pierce mines

256 JOURNAL OF PALEONTOLOGY, V. 83, NO. 2, 2009

FIGURE 14—Simpson ratio diagram comparing cheek tooth dimensions of Tapirus polkensis from the GFS (minimum, mean, and maximum) and CFPD(mean only) with means of other North American species of Tapirus from the Clarendonian and Hemphillian. Values plotted are log differences with meanvalues of extant Tapirus terrestris (negative values are smaller than T. terrestris; positive values larger than T. terrestris). Tooth measurements for the typespecimen of T. simpsoni taken from Schultz et al. (1975); means of T. webbi are from Hulbert (2005).

(Florida Geological Survey, 1959). Olson’s listing of the town ofPierce probably does not refer to the locality where the specimenswere collected, but rather was the location of the headquarters ofthat company. Olsen (1959) first listed ‘‘Tapiravus’’ from theCFPD with other taxa he thought were derived from the lowerBone Valley Formation (although without any stratigraphic datato support this) and he regarded this assemblage as Barstovian(Miocene) in age. Olsen (1960) was equivocal about whether T.polkensis came from the lower or upper Bone Valley Formation,although he favored the latter. Even though a Hemphillian, indeeda very late Hemphillian (Hh4), age was later established for the‘‘upper’’ Bone Valley fauna (e.g., Webb and Tessman, 1968;Webb, 1969, 1973; Tedford and Hunter, 1984), most subsequentworkers on tapirids not unreasonably interpreted Olsen’s (1959,1960) work to mean than T. polkensis was a member of one ofthe ‘‘lower’’ Bone Valley faunas, and regarded its age as Barsto-vian (Schultz et al., 1975; Savage and Russell, 1980; Schoch,1984). This was certainly compatible with the known early tomiddle Miocene age of other members of the genus Tapiravus.Numerous referred specimens of T. polkensis in the UF and UF/TRO collections have been collected in the CFPD in direct as-sociation with Hh4 species and none have been found in associ-ation with Barstovian or Clarendonian indicators (Hulbert, 2005;Webb et al., 2008). Hulbert (2005) also described a limited sampleof Hh2 T. polkensis from north-central Florida. Therefore, itschronologic range in Florida is now well constrained to be Hh2–Hh4.

Another note of clarification concerns the identification of thetwo teeth in MCZ 3808, the first tapirid reported from the CFPD(White, 1942). White (1942) originally identified them as dp2–

dp3. Olsen (1960, fig. 2) re-identified them as m2–m3, and thisinterpretation was followed by Schultz et al. (1975) and Schoch(1984). They are here considered to be the dp4–m1. The evidencefor this new identification is that the posterior tooth does not havea relatively narrow hypolophid, as is typical of tapirid m3s (in-cluding those of T. polkensis). The more anterior tooth (L � 17.9;AW � 12.7; PW � 12.4) has almost the same length as theposterior tooth, but is narrower and significantly more brachydont,a combination found only in the dp4 and m1 among adjacenttapirid molariform teeth. The dimensions of the anterior tooth fallwithin the OR of known dp4s of T. polkensis from the GFS (Table5). Also, the posterior tooth of MCZ 3808 is nearly identical insize and proportions (L � 18.2; AW � 13.3; PW � 12.7) toknown m1s of T. polkensis from the CFPD (e.g., UF/FGS 5942,UF 177740) and smaller than known m3s (Table 6).

Comparison between CFPD and GFS samples.⎯Although theCFPD sample of teeth and postcranial elements of Tapirus polk-ensis is on average smaller in size than the GFS sample, the over-lap in their ORs is great (Tables 2–5; Figs. 9, 10, 13, 14). Thedental morphologies of the two samples are the same. Althoughonly a few cranial characters are known for the CFPD population,they also match those found in the GFS sample. These includeposterior margin of zygomatic arch on maxilla at the level of thecenter of the M3 in adults (UF/TRO 1390; Fig. 10.3), large in-terparietal (based on the suture observed on UF 220447; Fig. 6.4),lambdoidal crest narrow with little lateral flair, and posterior sur-face of occipital dorsal to foramen magnum slanted posteroven-trally. Relative to the size of the teeth, the mandibles of the twopopulations have the same diastema length, muzzle width, man-dibular condyle height, and depth of the ramus below the p2 and

257HULBERT JR. ET AL.—LATE NEOGENE DWARF TAPIR

m3 (Table 3). In both samples the mental foramen is ventral tothe p2, the masseteric fossa is deep, the mandibular foramen is atthe same level or slightly above the molar crowns, and the man-dibular fossa is shallow but with numerous strong ridges on themedial surface of the dentary (Fig. 9). Given these morphologicsimilarities in the teeth, skull, and mandible, combined with ahigh degree of overlap in the OR of tooth L and W, we regardthese two samples as conspecific. The observed differences in sizecould be attributed to geographic variation (e.g., Bergmann’s re-sponse). Another factor could be the presence of a sympatric,medium-sized species of Tapirus in the Palmetto Fauna of theCFPD with T. polkensis (Hulbert, 1999; Webb et al., 2008). Thisas yet undescribed taxon is significantly larger than T. polkensis,but still relatively small compared to the extant members of thegenus (Fig. 14). Competitive displacement with this species,which is not present at the GFS, is a likely factor in the smallersize of the Florida population of T. polkensis.

Intraspecific variation in Tapirus polkensis.⎯The very largesample size of the GFS population of T. polkensis allows a rareopportunity to assess intraspecific variation in a fossil species ofTapirus, especially for characters of the skull. Many fossil speciesin the genus, even some described relatively recently (e.g., Tap-irus jeanpiveteaui Boeuf, 1991; Tapirus balkanicus Spassov andGinsburg, 1999; Tapirus mesopotamicus Ferrero and Noriega,2007), are known from a few specimens, in some cases only theholotype. The sample size of skulls from the GFS greatly exceedsthe known total of even relatively well known fossil species suchas Tapirus veroensis Sellards, 1918 (Lundelius and Slaughter,1976; Ray and Sanders, 1984). For some characters, such as theshape of the nasal bone, the morphology of the P1, and the dia-stema length, it is not surprising that the GFS sample reveals ahigh degree of individual variation, because they show a similarpattern in extant species of Tapirus (Hatcher, 1894; Simpson,1945; Hershkovitz, 1954; Ray and Sanders, 1984; Tables 2, 3).

As each of the four extant species of Tapirus has a distinctlydifferent morphology of the sagittal crest, this feature has beenwidely used in the description of fossil species (Simpson, 1945;Lundelius and Slaughter, 1976; Ray and Sanders, 1984; Hulbert,1995; Holbrook, 2002). Of all the species we have observed,modern and fossil, Tapirus polkensis is unique in having twodifferent morphologies for the parasagittal and sagittal crests. Inthe rarer morphology, found in about 25% of the individuals, theright and left parasagittal ridges of juveniles coalesce to form alow, ridge-like sagittal crest in adults (Fig. 7). This is the samestate consistently found in a number of other species, includingthe extant Tapirus pinchaque Roulin, 1829 and the fossil speciesTapirus veroensis. It probably is the plesiomorphic condition forthe genus (Hulbert and Wallace, 2005), and is also found in oldergenera in the family Tapiridae (Holbrook, 2002). In the morecommon morphology found in the GFS sample, low, roundedparasagittal ridges are retained throughout ontogeny and nevermerge to form a sagittal crest. Thus, the morphology characteristicof juvenile skulls in species such as T. pinchaque and T. veroensisis found in many of the full adults of T. polkensis (Fig. 6). Thiswould indicate a relatively weak temporalis muscle in T. polkensiscompared to other species of Tapirus (Holbrook, 2002). However,large mandibular and masseteric fossae on the dentary of T. polk-ensis imply that it retained well developed masseter and ptery-goideus jaw muscles. These differences in the relative develop-ment of the jaw muscles could reflect the availability of types offood in a temperate-climate deciduous forest compared to tropicalor semi-tropical conditions.

Generic allocation of Tapirus polkensis.⎯Tapirus polkensisshares with other species of Tapirus the following synapomor-phies: 1) presence of an anteromedial process on the maxilla; 2)posterior process of premaxilla ends dorsal to the P1 or moreanteriorly; 3) presence of a posterior lacrimal process; 4) widely

separated protocone and hypocone on P3 and P4; and 5) i2 no-tably smaller than i1 and i3 notably smaller than i2 (Hulbert andWallace, 2005; Wallace and Hulbert, 2005). A phylogenetic po-sition within the crown clade of Tapirus for T. polkensis is sup-ported by it having: 1) IOF located dorsal to P2 or P3; 2) incisiveforamen extends caudally to the level of the P1 or farther; 3)relatively molariform P2, with an average ratio of anterior to pos-terior width of 0.85 or greater; 4) mental foramen located ventralto p2; 5) tall, well separated transverse lophs and lophids on upperand lower premolars, respectively; 6) strongly developed paras-tyle on P3–M3; 7) i1 spatulate and procumbent; and 8) unwornhypolophid and protolophid on p2–p4 approximately equal inheight. A detailed phylogenetic analysis of all North Americantapirs, including T. polkensis, is under preparation by the authors.Ferrero and Noriega (2007:508) published a cladogram that in-cluded T. polkensis, which they described as ‘‘highly congruent’’with that of Hulbert and Wallace (2005). This is not surprising,considering that of the 34 characters used by Ferrero and Noriega(2007), 25 are identical to and were taken without attribution fromthe list of 79 characters and character states used by Hulbert andWallace (2005; published on-line at www.flmnh.ufl.edu/vertpaleo/tapirusresearch.htm), and two are slight modifications ofcharacters of Hulbert and Wallace (2005). The states scored formost Eurasian and North American fossil tapirids, including T.polkensis, in appendix 2 of Ferrero and Noriega (2007) appear tohave been copied from the character state matrix of Hulbert andWallace (2005). For these taxa, the states of Ferrero and Noriega’s(2007) seven original characters are shown as missing (their char-acter numbers 5, 26–30, and 32), even though many of them couldhave been scored if they had examined the actual fossils.

The diagnostic features and phylogenetic relationships of Tap-iravus Marsh, 1877 are most properly determined from its typespecies, Tapiravus validus (Marsh, 1871). The holotype of T. val-idus, YPM 13474, is an isolated upper premolar (figured and iden-tified as a P4 by Schoch, 1984) collected from the lower Kirk-wood Formation in southern New Jersey. Unfortunately, no otherspecimens have been collected from the type locality, nor fromequivalent age strata in the region (Schoch, 1984). The age ofYPM 13474 is now regarded as very early Miocene (Sugarmanet al., 1993; Benson, 1998; Tedford et al., 2004), and not middleor late Miocene as previously thought (Schlaikjer, 1937; Gazinand Collins, 1950; Olsen, 1960; Schoch, 1984). Until more nearlycomplete specimens are recovered from the Kirkwood Formationthat can be unambiguously attributed to T. validus and that revealdiagnostic characters to distinguish Tapiravus from other generain the Tapiridae, we regard the referral of middle Miocene oryounger tapirids to Tapiravus solely or primarily on the basis ofsimilar small size to be unsubstantiated. Almost all of the featureslisted by Schoch (1984) in his diagnosis of Tapiravus come fromsuch referred specimens, most notably USNM 18372 (Gazin andCollins, 1950) from the middle Miocene Calvert Formation ofMaryland, and Olsen’s (1960) holotype and paratype of T. polk-ensis from Florida.

The P4 of T. polkensis differs from YPM 13474 and resemblesthose of members of the crown clade of Tapirus in the followingphylogenetically significant character states (Hulbert and Wallace,2005): 1) greater hypsodonty; 2) larger parastyle; 3) more widelyseparated protoloph and metaloph (and protocone and hypocone);4) both the protoloph and metaloph unite high on the ectoloph,near the apices of the paracone and metacone, respectively, notat its base; 5) labial end of protoloph curves posterolabially toconnect with the paracone; and 6) metacone is not located rela-tively more lingual than the paracone. For some of these char-acters, YPM 13474 has a more plesiomorphic state than found inother tapirid genera, such as Paratapirus or Plesiotapirus, sug-gesting that Tapiravus is not the closest sister taxon to Tapirus.

Comparison with other North American fossil species.⎯All

258 JOURNAL OF PALEONTOLOGY, V. 83, NO. 2, 2009

other named North American fossil species of Tapirus are signif-icantly larger than Tapirus polkensis, with very little or no overlapin linear dimensions of the teeth, skull, or mandible (Fig. 14;Tables 2, 3). In the following comparisons, the indicated differ-ences in size are always relative, not absolute.

Tapirus johnsoni Schultz, Martin, and Corner, 1975 (Cl-earlyHh of Nebraska) differs morphologically from Tapirus polkensisby having 1) a taller dorsal flange on the maxilla; 2) IOF locateddorsal to P4; 3) two lacrimal foramina and a spicular posteriorlacrimal process; 4) a more limited meatal fossa on the frontaland nasal that does not near the midline; 5) a well formed sagittalcrest; 6) a small, diamond-shaped interparietal; 7) longer upperand lower postcanine diastemata (Tables 2, 3); 8) mental foramenlocated anterior to p2; and 9) cheek teeth more brachydont withlower lophs and lophids. The minimum width between the occip-ital condyles is about 14% of occipital condyle W in T. johnsoni,about half the value of T. polkensis. Tapirus simpsoni Schultz,Martin, and Corner, 1975 (Hh2 of Nebraska) differs from T. polk-ensis by having 1) incisive foramen ending more posteriorly, atthe level of the posterior margin of the P1; 2) IOF located dorsalto P4; 3) posterior margin of zygomatic process of the maxillalocated posterior to M3; and 4) wider upper cheek teeth. A moredetailed comparison is impossible because T. simpsoni is knownonly from a palate and two isolated teeth (Schultz et al., 1975).

Tapirus webbi Hulbert, 2005 (Cl3-Hh1 of Florida) differs mor-phologically from T. polkensis by having 1) IOF located dorsalto P4; 2) two lacrimal foramina and a spicular posterior lacrimalprocess; 3) meatal fossa limited to the posterolateral portion ofthe nasal, does not approach midline; 4) medial part of nasal verythick; 5) five- or six-sided interparietal; 6) smaller mandibulardepth posterior to m3 and mandibular condyle height (Table 3);and 7) narrower upper cheek teeth.

Tapirus haysii Leidy, 1859 (late Blancan-middle Irvingtonianof the eastern and central United States) differs from T. polkensisby having 1) posterior process of premaxilla ends near mid-pointof postcanine diastema; 2) IOF and lacrimal separated by a nar-rower bar of maxilla; 3) greater anteroposterior length of lacrimal;4) posterolateral margin of nasal bent sharply ventrally; 5) a wellformed sagittal crest; 6) lambdoidal crests project more laterally;7) back of skull dorsal to the foramen magnum is oriented ver-tically; 8) greater depth of the mandibular ramus (Table 3); 9)anterior margin of the ascending mandibular ramus projects an-teriorly in lateral view; 10) better development of transverse lophson P1 and P2; and 11) no posterolabial cingulum on upper cheekteeth (Hulbert, 1995). The minimum width between the occipitalcondyles is about 13% of occipital condyle W in T. haysii (N �2), about half the value of T. polkensis.

Tapirus veroensis Sellards, 1918 (late Irvingtonian-Ranchola-brean of the eastern and central United States) differs from T.polkensis by having 1) no dorsal flange on maxilla; 2) two largelacrimal foramina; 3) greater anteroposterior length of lacrimal;4) shorter nasal; 5) a well formed sagittal crest; 6) lambdoidalcrests project more laterally; 7) back of skull dorsal to the fora-men magnum is oriented vertically; 8) relatively greater depth ofmandibular ramus (Table 3); 9) anterior margin of the ascendingmandibular ramus projects anteriorly in lateral view; 10) betterdevelopment of transverse lophs on P1 and P2; and 11) no pos-terolabial cingulum on upper cheek teeth. The minimum widthbetween the occipital condyles is about 16% of occipital condyleW in T. veroensis (N � 2), about two-thirds the value of T.polkensis.

Tapirus merriami Frick, 1921 (late Blancan-Rancholabrean ofthe southwestern United States) is the largest species of Tapirusknown from North America (Jefferson, 1989). On average, itstooth dimensions exceed those of T. polkensis by 35 to 40%,without any overlap in their observed ranges. So there is no ques-tion that the two represent different species. However, there arefew morphologic characters other than size that distinguish the

two. Jefferson (1989, figs. 7, 8) described and figured a partialadult skull and associated partial mandible of T. merriami, LACM16057. As in T. polkensis, the parasagittal ridges of this specimenare not united to form a sagittal crest. A true sagittal crest ispresent in adult individuals of all other North American fossilspecies which preserve this region of the skull. A somewhat morenearly complete skull of a subadult individual of T. merriami alsohas parasagittal ridges instead of a sagittal crest (Jefferson, 1989,figs. 3–5). Other features shared by T. merriami and T. polkensis,although also commonly distributed among other North AmericanTapirus as well, are having the posterior process of the premaxillaend close to the anterior margin of the P1, mental foramen locatedventral to the p2, a relatively short lower postcanine diastema,and a relatively weak protoloph on the P2 which connects withthe parastyle. The only feature noted by Jefferson (1989) for T.merriami that differs from the condition found in T. polkensis isa more laterally projecting lambdoidal crest, but this can only beobserved on a single poorly preserved specimen. Most cranialcharacters can not be compared because they are not known forT. merriami. Tapirus californicus Merriam, 1913 from the Ran-cholabrean of California (Jefferson, 1989) is known only fromisolated teeth and fragmentary maxillae and mandibles. The toothmeasurements provided by Jefferson (1989), including those ofthe holotype, all exceed the observed ranges for T. polkensis (Fig.14). No other comparisons are possible at this time.

Comparison with South American fossil and extant spe-cies.⎯The only South American fossil species of Tapirus that isknown from a relatively complete skull is the recently describedTapirus mesopotamicus Ferrego and Noriega, 2007. It is a Pleis-tocene species from Argentina thought to be related to T. pin-chaque (Ferrego and Noriega, 2007). T. mesopotamicus is sub-stantially larger than T. polkensis (Table 2), and differs from itby having 1) anteromedial process of maxilla covered by pre-maxilla and not clearly visible in lateral view; 2) smaller meatalfossa on dorsal surface of nasal and frontal which does not extendnear the midline; 3) spicular posterior lacrimal process; 4) tallersagittal crest; 5) absence of anteromedial process of frontal; and6) absence of dorsal maxillary flange.

In addition to its significantly smaller size (Tables 2, 3), Tapiruspolkensis is qualitatively different from all three extant Neotrop-ical species of Tapirus. It differs from Tapirus bairdii (Gill, 1865)in having 1) nasals and frontals on the same plane; 2) a broad,shallow supraorbital groove for nasal diverticulum; 3) a shallowernasal notch; 4) dorsal border of maxilla directed medially andwith a much slighter flange; 5) mesethmoid cartilage not ossified;6) a longer posterior process of premaxilla; and 7) relatively shortpostcanine diastema. The minimum width between the occipitalcondyles is about 14% of occipital condyle W in T. bairdii (N �2), about half the value of T. polkensis. It differs from Tapirusterrestris in having 1) parasagittal ridges either not fused into asagittal crest, or, if a sagittal crest is present, it is much lower andnot strongly arched; 2) nasals and frontals on the same plane; 3)large, distinct interparietal bone in juveniles; 4) larger meatal fos-sa on dorsal surface of nasal and frontal which extends near themidline; 5) anteromedial process of maxilla well exposed in lat-eral view; 6) posterior lacrimal process broad and flat; 7) onelacrimal foramen that is not visible in lateral view; 8) posterola-bial cingulum frequently present on P3–M3; and 9) relativelyshort postcanine diastema. The minimum width between the oc-cipital condyles is about 8% of occipital condyle W in T. terrestris(N � 3), about one-third of the value in T. polkensis. It differsfrom Tapirus pinchaque in having 1) parasagittal ridges either notfused into a sagittal crest, or, if a sagittal crest is present, it formslater in ontogeny; 2) larger, triangular interparietal; 3) relativelyshorter nasal bone; 4) anteromedial process of maxilla well ex-posed in lateral view; 5) larger meatal fossa on dorsal surface ofnasal and frontal which extends near the midline; 6) anteromedialprocess of frontals extends rostrally between nasals; 7) posterior

259HULBERT JR. ET AL.—LATE NEOGENE DWARF TAPIR

FIGURE 15—Simpson ratio diagram comparing cheek tooth dimensions of Tapirus polkensis from the GFS (minimum, mean, and maximum) with those ofEuropean fossil species of Tapirus. Format as in Figure 14. Tooth measurements or statistics taken from Boeuf (1991), T. jeanpiveteaui (upper dentition only);Spassov and Ginsburg (1999), T. balkanicus; and Guerin and Eisenmann (1994), T. pannonicus (p2–p4 only), T. arvernensis, and T. priscus.

lacrimal process broad and flat; 8) one lacrimal foramen that isnot visible in lateral view; and 9) broader P1. The minimum widthbetween the occipital condyles is about 17% of occipital condyleW in T. pinchaque (N � 1), about two-thirds the value of T.polkensis.

Comparison with Eurasian fossil and extant species.⎯In thePalmetto Fauna of Florida, Tapirus polkensis is found in associ-ated with several taxa that had recently dispersed from or origi-nated in Asia (Webb et al., 2008), including the flying squirrelMiopetaurista webbi (Robertson, 1976), the odocoiline cervidEocoileus gentryorum Webb, 2000, the mustelid Plesiogulo mar-shalli (Martin, 1928), and the ursids Plionarctos sp. and Agri-otherium schneideri Sellards, 1916, as well as at least one speciesthat dispersed from North America into Asia, the canid Eucyondavisi (Merriam, 1911). The GFS has an Asian component in itsfauna as well, with the presence of Plionarctos, the red pandaPristinailurus bristoli Wallace and Wang, 2004, and a ‘‘Eurasian’’badger Arctomeles dimolodontus Wallace and Wang, 2004. Theecological requirements of some of these taxa indicate periodicavailability of continuous forested habitat from the eastern US,across Canada and the Bering land bridge, and extending wellinto Eurasia in the late Miocene and early Pliocene. Althoughextant tapirs are often considered tropical, the mountain tapir Tap-irus pinchaque lives in relatively cool temperatures at high alti-tudes in the Andes (Hershkovitz, 1954). It is the availability ofyear-round forage and water that limits the distribution of tapirs,not temperature. The fossil record of Tapirus is as long if notlonger in Eurasia than in North America (Guerin and Eisenmann,

1994), and the genus must have dispersed at least once (in an asyet uncertain direction) between the two in the middle Miocene.

The best known tapirs from the late Neogene of Europe areTapirus priscus Kaup, 1833 of the late Miocene and Tapirus arv-ernensis Croizet and Jobert, 1828 of the Pliocene. Published mea-surements indicate that both are significantly larger than Tapiruspolkensis (Fejfar, 1964; Rustioni, 1992; Guerin and Eisenmann,1994; Fig. 15). The P2 of T. priscus has a lower AW/PW ratiothan T. polkensis. The P3–P4 of T. priscus, and to a lesser degreethose of T. arvernensis, are relatively narrower than those of T.polkensis. The mandibular condyle height of T. priscus is rela-tively much greater than that of T. polkensis. Tapirus arvernensisdiffers from T. polkensis by having the mental foramen locatedanterior to the p2, i1 and i2 of similar size, very short posteriorprocess of the premaxilla, and dorsal surface of nasal is positionedlower than that of the frontal (Rustioni, 1992).

Of greater interest are the presence of three named species ofsmall tapirs in the late Neogene of Europe: ‘‘Tapiriscus’’ pan-nonicus Kretzoi, 1951; Tapirus jeanpiveteaui Boeuf, 1991; andTapirus balkanicus Spassov and Ginsburg, 1999. The dental di-mensions of all three fall within or close to the OR of Tapiruspolkensis (Fig. 15). Each is known from very limited samples(generally N � 1 for any tooth position), so assessment of intra-specific variation is impossible. Spassov and Ginsburg (1999) em-phasized the differences between the upper premolars of the ho-lotype of T. jeanpiveteaui (generally less molarized premolars,weaker P2 protoloph and metaloph, one lingual cusp on P1) andthose of the holotype of T. balkanicus (broader P3–P4, stronger

260 JOURNAL OF PALEONTOLOGY, V. 83, NO. 2, 2009

P2 protoloph and metaloph, two lingual cusps on P1). When largesamples (N � 20) are available, many of these characters showconsiderable intraspecific variation (e.g., T. polkensis, this study;T. indicus, Hooijer, 1947; T. webbi, Hulbert, 2005; T. sinensis,Tong, 2005). Larger samples, ideally including better preservedspecimens, are needed to prove Spassov and Ginsburg (1999)were correct in regarding the two as specifically distinct. Theholotype of T. jeanpiveteaui is a badly crushed skull (Boeuf,1991). Nevertheless, it does preserve several characters that clear-ly differentiate it from T. polkensis, most notably the presence ofa strong sagittal crest, extremely broad nasals, shorter M3, andgreatly narrower AW of its P2–P4.

The reported dimensions of the holotype upper dental series ofTapirus balkanicus fall close to or just above the upper range ofTapirus polkensis (Fig. 15). The P2–P4 have a strong lingual cin-gulum (Spassov and Ginsburg, 1999), a feature not observed onthese teeth in T. polkensis. Another difference is that molar lengthis shorter relative to width in T. balkanicus. The referred partialmandible of T. balkanicus is from a different locality than theholotype (Spassov and Ginsburg, 1999), and its tooth dimensionsare all below the mean values of T. polkensis, and instead fallclose to or even below the minimum values of T. polkensis (Fig.15). This strongly suggests that the two specimens of T. balkan-icus described by Spassov and Ginsburg (1999) are not conspe-cific, and the mandible is more properly referred to a smallerspecies of Tapirus, such as the similar sized T. pannonicus. How-ever, unless more nearly complete material can be confidentlyreferred to T. pannonicus, its status as a valid taxon is doubtful.

There are no good records of late Miocene or early PlioceneTapirus from China, but two late Pliocene species, Tapirus san-yuanensis Huang, 1991 and Tapirus sinensis Owen, 1870, arerelatively well known (Tong et al., 2002; Tong, 2004, 2005).Based on the published measurements in these papers, both spe-cies are much larger than T. polkensis. According to Tong (2005),T. sanyuanensis is closely related to the extant Tapirus indicusDesmarest, 1819, while T. sinensis is closely related to the verylarge species of the Asian Pleistocene, Tapirus augustus Matthewand Granger, 1923. While there are some similarities between T.polkensis and T. indicus, including development of a small dorsalflange on the anteromedial process of the maxilla and the poster-oventral slant on the posterior surface of the occipital dorsal tothe foramen magnum, there are considerable differences in themorphology of the lacrimal, nasal, and frontal bones. Also, whilethere is some similarity in that neither typically forms a narrowsagittal crest, the parasagittal crests in T. indicus are sharper andmuch taller than the surrounding bone of the parietal, the upperdiastema is relatively longer (Table 2), and the mandibular depthbelow the p2 is relatively greater (Table 3). Also, minimum Wbetween the occipital condyles in T. indicus is only about 9% ofoccipital condyle W (N � 2), while it is greater than 21% in T.polkensis.

Estimated body mass of Tapirus polkensis.⎯As no tapir-spe-cific regression equations relating mass to dimensions of bonesor teeth are available, we used two of the all-ungulate regressionspublished by Scott (1990) for postcranial elements, and two ofthe all-ungulate regressions using molar dimensions of Janis(1990). These four provided better mass estimates for extant tapirsbased on their known values than did other parameters. Tapiruspolkensis has mean values of 46.6, 64.3, 19.8, and 20.4 mm fordistal W of the humerus (N � 13), proximal W of the tibia (N� 10), M2 L (N � 41), and m2 L (N � 33), respectively. Afterconversion to centimeters, when placed into the appropriate re-gression equations of Scott (1990) and Janis (1990), they produceestimates of mass of 129, 114, 117, and 140 kg. The average ofthese four values is 125 kg. The same four parameters producedestimated average masses of 184 kg for extant Tapirus terrestris,223 kg for Tapirus bairdii, and 287 kg for Tapirus indicus. Theseestimates fall inside the known values of the extant species and

reflect their known relative sizes (Hershkovitz, 1954; Padilla andDowler, 1994), supporting our estimated mass of T. polkensis.

CONCLUSIONS

Like many fossil species of tapirids, ‘‘Tapiravus’’ polkensiswas long known from a very limited sample. Intense collectingin the type region of central Florida produced more specimens,which allowed a better estimate of size variation in its lowercheek teeth and produced the first known upper molars of thespecies. Many of the new specimens were collected in situ withfossils of species characteristic of the late Hemphillian land mam-mal age, (see review in Webb et al., 2008). Surprisingly, no spec-imens of ‘‘T.’’ polkensis were recovered from relatively fossilif-erous Barstovian and Clarendonian sites collected in the CFPD inthe 1970s and 1980s, as this was the assumed age of Olsen’s(1960) original sample. Yarnell’s (1980) purported middle Mio-cene specimens of ‘‘T.’’ polkensis, most notably UF/TRO 1390,are late Hemphillian based on corrected identifications of asso-ciated equid teeth and other fossils. The increased sample of teethfrom the CFPD showed greater affinity with those of Tapirus,although of distinctly small size, which was more in accord withtheir younger geologic age (Hulbert, 1999; Hulbert et al., 2001).

It was the enormous sample of small tapir skulls, mandibles,and in many cases associated or articulated skeletons (Fig. 2.2)produced by the GFS in Tennessee that clearly showed that Ol-sen’s species was a member of Tapirus rather than Tapiravus(Hulbert and Wallace, 2005). The sample allows detailed analysisof intraspecific and ontogenetic variation, some not before ob-served in fossil tapirs. In particular, the reduced parasagittal crest,which generally does not unite to form a sagittal crest but insteadretains the juvenile condition into the full adult stage (with someexceptions) is unique within the genus, and is perhaps related tosome combination of small adult size and differences in jaw me-chanics that favored use of the masseter and pterygoideus musclesover the temporalis. If Tapirus merriami proves to have the samecondition, as hinted at by a few poorly preserved specimens, thenbody size is not a factor, as it is one of the largest known speciesin the genus. As only a relatively small percentage of the GFShas been excavated, the already extensive sample of Tapirus polk-ensis will continue to increase, providing an even richer resourceto study all aspects of its paleobiology.

ACKNOWLEDGMENTS

The accumulated specimens of Tapirus polkensis from both theCFPD and the GFS are the result of the efforts and generosity ofmany persons. For the CFPD, stratigraphic collecting in the regionwas pioneered by S. D. Webb and J. S. Waldrop; J. Ranson, J. S.Waldrop, P. Whisler, and R. Carter donated specimens to the UFcollection; and B. Fite allowed molds and casts to be made ofspecimens in her private collection. For the GFS, we thank theTennessee Department of Transportation for bringing attention tothe site and for its subsequent protection and preservation; formerGovernor Don Sundquist for the funds necessary to construct theMuseum of Natural History and for the initiation of the DonSundquist Center of Excellence in Paleontology; Provost and VicePresident of Academic Affairs Bert Bach of ETSU for additionalfunding of our field and lab crew; R. Noseworthy and H. Moorefor access to their specimens; and J. Supplee, S. Haugrud, B.Compton, A. Nye, M. Adams and many students, staff and vol-unteers for their skilled preparation.

The Florida portion of this study was initiated by Hulbert whenhe was on the faculty of Georgia Southern University and hisresearch on fossil tapirs was funded by the Georgia Southern Uni-versity Foundation and Faculty Research Subcommittee. Wethank M. W. Colbert and L. T. Holbrook for their helpful reviewsof the paper. This is University of Florida Contribution to Paleo-biology 610.

261HULBERT JR. ET AL.—LATE NEOGENE DWARF TAPIR

REFERENCES

BENSON, R. N. 1998. Radiolarians and diatoms from the Pollack Farm Site,Delaware: marine-terrestrial correlation of Miocene vertebrate assemblagesof the middle Atlantic Coastal Plain, pp. 5–19. In R. N. Benson (ed.),Geology and Paleontology of the Lower Miocene Pollack Farm Fossil Site,Delaware. Delaware Geological Survey Special Publication 21.

BOEUF, O. 1991. Tapirus jeanpiveteaui nov. sp., nouvelle espece de Tapiridae(Perissodactyla) du Pliocene de Charente (France). Palaeontographica, Ab-teilung A, 217:177–194.

COLBERT, M. W. 2005. The facial skeleton of the early Oligocene Colodon(Perissodactyla, Tapiroidea). Paleontologica Electronica, 8:12A �http://palaeo-electronica.org/2005�1/colbert12/issue1�05.html�

COLBERT, M. W. AND R. M. SCHOCH. 1998. Tapiroidea and other moropo-morphs, pp. 569–582. In C. M. Janis, K. S. Scott, and L. L. Jacobs (eds.),Evolution of Tertiary Mammals of North America, Volume 1: TerrestrialCarnivores, Ungulates, and Ungulatelike Mammals. Cambridge UniversityPress, Cambridge.

COOK, H. J. 1927. A new rhinoceros of the genus Teleoceras from Colorado.Proceedings of the Colorado Museum of Natural History, 7:1–5.

CROIZET, J.-B. AND A. C. G. JOBERT. 1828. Reserches sur les OssementsFossiles du Department du Puy-de-Dome. Paris, 224 p.

DESANTIS, L. R. G. AND S. C. WALLACE. 2008. Neogene forest refugiumfrom the Appalachians of Tennessee, USA: Geochemical evidence fromfossil mammal teeth. Palaeogeography, Palaeoclimatology, Palaeoecology,266:59–68.

DESMAREST, A. G. 1819. Tapirs fossiles, pp. 458–461. In Nouveau Diction-naire d’Histoire Naturelle (ed.), Nouvelle Edition. Chez Deterville, Paris,vol. 32.

FEJAR, O. 1964. The lower-Villafranchian vertebrates from Hajnacka nearFilakovo in southern Slovakia. Ustrednı Ustav Geologicky, Praha, 116 pp.

FERRERO, B. S. AND J. I. NORIEGA. 2007. A new upper Pleistocene tapir fromArgentina: remarks on the phylogenetics and diversification of NeotropicalTapiridae. Journal of Vertebrate Paleontology, 27:504–511.

FLORIDA GEOLOGICAL SURVEY. 1959. Known active mineral producers ofFlorida 1956–1957. Biennial Report, Florida Geological Survey, 13:70–84.

FRICK, C. 1921. Extinct vertebrate faunas of the badlands of Bautista Creekand San Timoteo Canon, southern California. University of California Pub-lications, Bulletin of the Department of Geology, 12:277–424.

FRICK, C. 1926. The Hemicyoninae and an American Tertiary bear. Bulletinof the American Museum of Natural History, 56:1–119.

GAZIN, C. L. AND R. L. COLLINS. 1950. Remains of land mammals from theMiocene of the Chesapeake Bay Region. Smithsonian Miscellaneous Col-lections, 116(2):1–21.

GILL, T. N. 1865. Description of the genus Elasmognathus. Proceedings ofthe Academy of Natural Sciences Philadelphia, 17:183.

GUERIN, C. AND V. EISENMANN. 1994. Les tapirs (Mammalia, Perissodactyla)du Miocene superieur d’Europe occidentale. Geobios, 27:113–127.

HATCHER, J. B. 1894. A median horned rhinoceros from the Loup Fork Bedsof Nebraska. American Geologist, 13:149–150.

HERSHKOVITZ, P. 1954. Mammals of northern Colombia, preliminary reportno. 7: tapirs (genus Tapirus), with a systematic review of American species.Proceedings of the United States National Museum, 103:465–496.

HOLBROOK, L. T. 2002. The unusual development of the sagittal crest in theBrazilian tapir (Tapirus terrestris). Journal of Zoology, London, 256:215–219.

HOOIJER, D. A. 1947. On fossil and prehistoric remains of Tapirus from Java,Sumatra, and China. Zoologische Mededeelingen Museum Leiden, 27:253–299.

HUANG, W. AND F. QIREN. 1991. Wushan Homind Site. China Ocean Press,Beijing, 205 p. (In Chinese)

HULBERT, R. C. 1995. The giant tapir, Tapirus haysii, from Leisey Shell Pit1A and other Florida Irvingtonian localities. Bulletin of the Florida Mu-seum of Natural History, 37:515–551.

HULBERT, R. C. 1999. Nine million years of Tapirus (Mammalia, Perisso-dactyla) from Florida. Journal of Vertebrate Paleontology, 19(3, supple-ment):53A.

HULBERT, R. C. 2005. Late Miocene Tapirus (Mammalia, Perissodactyla)from Florida, with description of a new species, Tapirus webbi. Bulletin ofthe Florida Museum of Natural History, 45:465–494.

HULBERT, R. C., B. J. MACFADDEN, AND J. S. WALDROP. 2001. Perissodac-tyla, pp. 280–306. In R. C. Hulbert (ed.), The Fossil Vertebrates of Florida.University Press of Florida, Gainesville.

HULBERT, R. C. AND S. C. WALLACE. 2005. Phylogenetic analysis of lateCenozoic Tapirus (Mammalia, Perissodactyla). Journal of Vertebrate Pa-leontology, 25(3, supplement):72A.

JANIS, C. M. 1990. Correlation of cranial and dental variables with body sizein ungulates and macropodids, pp. 255–291. In J. Damuth and B. J.MacFadden (eds.), Body Size in Mammalian Paleobiology, Estimation andBiological Implications. Cambridge University Press, Cambridge.

JEFFERSON, G. T. 1989. Late Cenozoic tapirs (Mammalia: Perissodactyla) ofwestern North America. Los Angeles County Museum Contributions inScience, Number 406, 21 p.

KAUP, J. J. 1833. Description d’ossements fossils de Mammiferes inconnusjusqu’a present, qui se trouvent au Museum grand-ducal de Darmstadt.2eme cahier (Chalicotherium, Tapir, Porcs, Carnivores). Darmstadt, 31 pp.

KRETZOI, M. 1951. The Hipparion-fauna von Csakvar. Foldtany Kozlony, 81:402–417.

LEIDY, J. 1859. Descriptions of vertebrate fossils, pp. 99–122. In F. S. Holmes(ed.), Post-Pleiocene Fossils of South Carolina. Russell and Jones, Charles-ton.

LINNAEUS, C. 1758. Systema naturae per regna tria naturae, secundum classes,ordines, genera, species, cum characteribus differentiis, synonymis, locis.Tenth Edition. Laurentii Salvii, Stockholm, 824 p.

LUNDELIUS, E. L. AND B. H. SLAUGHTER. 1976. Notes on American Pleis-tocene tapirs, pp. 226–243. In C. S. Churcher (ed.), Athlon: Essays in Pa-leobiology in Honour of Loris Shano Russell. Royal Ontario Museum, To-ronto.

MARSH, O. C. 1871. Description of Lophiodon validus. Proceedings of theAcademy of Natural Sciences, Philadelphia, 23:9–10.

MARSH, O. C. 1877. Notice of some new vertebrate fossils. American Journalof Science, series 3, 14:249–256.

MARTIN, H. T. 1928. Two new carnivores from the Pliocene of Kansas. Jour-nal of Mammalogy, 9:233–236.

MATTHEW, W. D. AND W. GRANGER. 1923. New fossil mammals from thePliocene of Szechuan, China. Bulletin of the American Museum of NaturalHistory, 48:563–598.

MERRIAM, J. C. 1911. Tertiary mammal beds of Virgin Valley and ThousandCreek in northwestern Nevada. University of California Publications, Bul-letin of the Department of Geological Sciences, 6:199–304.

MERRIAM, J. C. 1913. Tapir remains from late Cenozoic beds of the Pacificcoast region. University of California Publications, Bulletin of the Depart-ment of Geology, 7:169–175.

OLSEN, S. J. 1959. Fossil mammals of Florida. Florida Geological SurveySpecial Publication Number 6, 75 p.

OLSEN, S. J. 1960. Age and faunal relationships of Tapiravus remains fromFlorida. Journal of Paleontology, 34:164–167.

OWEN, R. 1870. On fossil remains of mammals found in China. Journal ofthe Geological Society of London, 26:417–434.

PADILLA, M. AND R. C. DOWLER. 1994. Tapirus terrestris. Mammalian Spe-cies, Number 481, 8 p.

PARMALEE, P. W., W. E. KLIPPEL, P. A. MEYLAN, AND J. A. HOLMAN. 2002.A Late Miocene-early Pliocene population of Trachemys (Testudines: Emy-didae) from East Tennessee. Annals of the Carnegie Museum of NaturalHistory, 71:233–239.

RAY, C. AND A. E. SANDERS. 1984. Pleistocene tapirs in the eastern UnitedStates, pp. 283–315. In H. H. Genoways and M. R. Dawson (eds.), Con-tributions in Quaternary Vertebrate Paleontology: A Volume in Memorialto John E. Guilday. Carnegie Museum of Natural History, Pittsburgh, Spe-cial Publication 8.

ROBERTSON, J. S. 1976. Latest Pliocene mammals from Haile XVA, AlachuaCounty, Florida. Bulletin of the Florida State Museum, 20:111–186.

ROULIN, X. 1829. Memoir pour servir a l’histoire du tapir; et description duneespece nouvelle appartenant aux hautes regions de la Cordillere des Andes.Annales des Sciences Naturelle Zoologie Paris, 17:26–55.

RUSTIONI, M. 1992. On Pliocene tapirs from France and Italy. Bollettino dellaSocieta Paleontologica Italiana, 31:269–294.

SAVAGE, D. E. AND D. E. RUSSELL. 1983. Mammalian Paleofaunas of theWorld. Addison-Wesley, Reading, Massachusetts, 432 p.

SCHLAIKJER, E. M. 1937. A new tapir from the lower Miocene of Wyoming.Bulletin of the Museum of Comparative Zoology, 80:231–251.

SCHOCH, R. M. 1984. The type specimens of Tapiravus validus and ?Tapi-ravus rarus (Mammalia, Perissodactyla), with a review of the genus, anda new report of Miotapirus (Miotapirus marslandensis Schoch and Prins,new species) from Nebraska. Postilla, Number 195, 12 p.

SCHUBERT, B. W. AND S. C. WALLACE. 2006. Amphibians and reptiles of theMio-Pliocene Gray Fossil Site and their paleoecologic implications. Journalof Vertebrate Paleontology, 26(supplement to 3:122A.

SCHULTZ, C. B., L. D. MARTIN, AND R. G. CORNER. 1975. Middle and lateCenozoic tapirs from Nebraska. Bulletin of the Nebraska State Museum,10:1–21.

SCOTT, K. M. 1990. Postcranial dimensions of ungulates as predictors of bodysize, pp. 301–335. In J. Damuth and B. J. MacFadden (eds.), Body Size inMammalian Paleobiology, Estimation and Biological Implications. Cam-bridge University Press, Cambridge.

SELLARDS, E. H. 1916. Fossil vertebrates from Florida: a new Miocene fauna;new Pliocene species; the Pleistocene fauna. Annual Report, Florida Geo-logical Survey, 8:77–119.

SELLARDS, E. H. 1918. The skull of a Pleistocene tapir including description

262 JOURNAL OF PALEONTOLOGY, V. 83, NO. 2, 2009

of a new species and a note on the associated fauna and flora. AnnualReport, Florida Geological Survey, 10:57–70.

SIMPSON, G. G. 1945. Notes on Pleistocene and Recent tapirs. Bulletin of theAmerican Museum of Natural History, 86:33–82.

SHUNK, A., S. G. DRIESE, AND G. M. CLARK. 2006. Latest Miocene to earliestPliocene sedimentation and climate record derived from paleosinkhole filldeposits, Gray Fossil Site, northeastern Tennessee, U.S.A. Palaeogeogra-phy, Palaeoclimatology, Palaeoecology, 231:265–278.

SPASSOV, N. AND L. GINSBURG. 1999. Tapirus balkanicus nov. sp., nouveautapir (Perissodactyla, Mammalia) du Turolien de Bulgarie. Annales de Pa-leontologie, 85:265–276.

SUGARMAN, P. J., K. G. MILLER, J. P. OWENS, AND M. D. FEIGENSON. 1993.Strontium-isotope and sequence stratigraphy of the Miocene Kirkwood For-mation, southern New Jersey. Geological Society of America Bulletin, 105:423–436.

TEDFORD, R. H. AND M. E. HUNTER. 1984. Miocene marine-nonmarine cor-relations, Atlantic and Gulf Coastal Plains, North America. Palaeogeogra-phy, Palaeoclimatology, Palaeoecology, 47:126–151.

TEDFORD, R. H., L. B. ALBRIGHT, A. D. BARNOSKY, I. FERRUSQUILA-VIL-LAFRANCA, R. M. HUNT, J. E. STORER, C. C. SWISHER, M. R. VOORHIES,S. D. WEBB, AND D. P. WHISTLER. 2004. Mammalian biochronology of theArikareean through Hemphillian interval (late Oligocene through earliestPliocene epochs) in North America, pp. 169–231, In M. O. Woodburne(ed.), Late Cretaceous and Cenozoic Mammals of North America: Biostra-tigraphy and Geochronology. New York, Columbia University Press.

TONG, H. 2004. Tapiridae, pp. 233–250. In S. Zheng (ed.), Jianshi HominidSite. Science Press, Beijing. (In Chinese)

TONG, H. 2005. Dental characters of the Quaternary tapirs in China, theirsignificance in classification and phylogenetic assessment. Geobios, 38:139–150.

TONG, H., J. LIU, AND L. HAN. 2002. On fossil remains of early Pleistocenetapir (Perissodactyla, Mammalia) from Fanchang, Anhui. Chinese ScienceBulletin, 47:586–590.

WALLACE, S. C. AND R. C. HULBERT. 2005. Morphology and systematics of

the Hemphillian (Miocene) Gray Fossil Site tapir. Journal of VertebratePaleontology, 25(3, supplement):127A.

WALLACE, S. C., J. NAVE, AND K. BURDICK. 2002. Preliminary report on therecently discovered Gray Fossil Site (Miocene), Washington Co., Tennes-see: with comments on observed paleopathologies – the advantages of alarge sample. Journal of Vertebrate Paleontology, 22(3, supplement):117A.

WALLACE, S. C. AND X. WANG. 2004. Two new carnivores from an unusuallate Tertiary forest biota in eastern North America. Nature, 431:556–559.

WEBB, S. D. 1969. The Pliocene Canidae of Florida. Bulletin of the FloridaState Museum, 14:273–308.

WEBB, S. D. 1973. Pliocene pronghorns of Florida. Journal of Mammalogy,54:203–221.

WEBB, S. D. 2000. Evolutionary history of New World Cervidae, pp. 38–64.In E. Vrba and G. Schaller (eds.), Antelopes, Deer, and Relatives: FossilRecord Behavioral Ecology, Systematics and Conservation. Yale UniversityPress, New Haven.

WEBB, S. D. AND R. C. HULBERT. 1986. Systematics and evolution of Pseu-dhipparion (Mammalia, Equidae) from the Late Neogene of the Gulf Coast-al Plain and the Great Plains, pp. 237–272. In K. M. Flanagan and J. A.Lillegraven (eds.), Vertebrates, Phylogeny, and Philosophy. University ofWyoming Contributions to Geology, Special Paper 3.

WEBB, S. D., R. C. HULBERT, G. S. MORGAN, AND H. F. EVANS. 2008. Ter-restrial mammals of the Palmetto Fauna (early Pliocene, latest Hemphillian)from the Central Florida Phosphate District, pp. 293–312. In X. Wang andL. G. Barnes (eds.), Geology and Vertebrate Paleontology of Western andSouthern North America, Contributions in Honor of David P. Whistler. Nat-ural History Museum of Los Angeles County Science Series, Number 41.

WEBB, S. D. AND N. TESSMAN. 1968. A Pliocene vertebrate fauna from lowelevation in Manatee County, Florida. American Journal of Science, 266:777–811.

WHITE, T. E. 1942. Additions to the fauna of the Florida phosphates. Pro-ceedings of the New England Zoology Club, 21:87–91.

YARNELL, K. L. 1980. Systematics of late Miocene Tapiridae (Mammalia,Perissodactyla) from Florida and Nebraska. Unpublished M.S. thesis, Uni-versity of Florida, Gainesville, 125 p.

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