-FLORIDA
_MUSEUM BULLETI

OF NATURAL HISTORY

THREE-TOED BROWSING HORSE
ANCHITHERIUM CLARENCEI

FROM THE EARLY MIOCENE (HEMINGFORDIAN)
THOMAS FARM, FLORIDA

Bruce J. MacFadden

Vol. 43, No. 3, pp. 79-109 2001

UNIVERSITY OF FLORIDA GAINESVILLE



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THREE-TOED BROWSING HORSE ANCHIRIERIUM CLLRENCEI
FROM THE EARLY MIOCENE (HEMINGFORDIAN) THOMAS FARM, FLORIDA

Bruce J. MacFadden'

ABSTRACT
Anchitherium clamncei Simpson 1932 is described from the early Miocene (early Hemingfordian, ca. 18 million-year-old)
ThomasFarm locality innorth central Florida. This rarespecies ofthree-toedbrowsing horse demonstrates diagnostic characters
including a reduced m3 hypoconutid heel and relatively robust metapodials, both of which also differentiate Anchitherium
from its close relative Kalobatippus. The distinctness of these two genera has been questioned for 85 years. Some workers
argue that Anchitherium Meyer 1844 is the senior synonym of Kalobatippus Osborn 1915, with the former genus being
distributed throughout Holarctica during the Miocene. Other workers believe that Ka/obatippus is restricted to the New World
whereasAnchitherium is restricted tothe Old World during the Miocene. Intheinterpretation presented here, both Kalobatippus
andAnchitherium occur as distinct genera in North America, with the former found principally in Arikareean faunas and the
latter found principally in Hemingfordian faunas (although A. clarencei extends into the early Barstovian in Florida). New
WorldAnchitherium sensu stricto, such asA. clamncei, has the derived characters shared with Old World species ofAnchitherium.
The postcranial morphology represented by A. clarencei from Thomas Farm indicates relatively flexible fore- and hind-limbs
with functional tridactyly.

Key words: Anchitherium, Equidae, Florida, Kalobatippus, Miocene

RESUMEN
Se describe a Anchitherium clarencei Simpson 1932 de la localidad Thomas Farm, regi6n centro-none de Florida  Mioceno
Temprano (Hemingfordiano Temprano, ca. 18 millones de afios). Esta rara especie de 6quido tridktilo ramoneador muestra
rasgos diagntsticos que incluyen un talon con hipocondlido reducido sobre el m3 y metapodiales relativamente robustos;
ambos caracteres diferencian a Anchitherium de su pariente mAs cercano Kalobatippus. Por 85 afios, la validez de estos dos
g6neros se ha cuestionado. Algunos investigadores argumentan que Anchitherium Meyer 1844 es el sin6nimo senior de
KWobatippus Osborn 1915, y que el primero se encuentra distribuido al travts del Dominio Hol~rtico durante el Mioceno.
Otros autores sugieren que para dicho intervalo de tiempo Kalobatippus se restringe al Nuevo MundoyAnchitherium al Viejo
Mundo. En la interpretaci6n que se presenta aqui tanto Kalobatippus comoAnchitherium seencuentran comog6neros diferentes
en Norteamdrica. el primero reconocido para las faunas arikareanas y el segundo fundamentalmente en las hemingfordianas
(aunque A. clamncei se reconoce para el Barstoviano Temprano de Florida). El Anchitherium sensu stricto del NuevoMundo,
tal es el caso de A. clarencei, presenta rasgos derivados que comparte con las especies del Viejo Mundo de Anchitherium. La
morfologia postcraneal de A. clamncei de Thomas Farm, indica extremidades anterioresy posteriores relativamente flexibles,
con tridactilia funcional.

TABLE OF CONTENTS

Introduction 80
Acknowledgments 80
History and Nomenclature ofAnchitherium Meyer 1844

and Kalobatippus Osborn 1915 80
Materials, Methods, Terminology, and Abbreviations 85
Systematic Paleontology

GenusAnchitherium Meyer 1844 86
Anchitherium clarencei Simpson 1932 88

Discussion 104
Anchitherium Meyer 1844 and Kalobatippus Osborn 1915 104
Thomas Farm Anchitherium clarencei and Old World dispersal 105

Summary and Conclusions 107
Literature Cited 108

1The author is Associate Director of Exhibits & Public Programs and Curator of Vertebrate Paleontology, Florida Museum of Natural History University of
Florida. Gainesville FL 32611-2710, email: bmacfadd@fimnkufl.edu.

B. J. MacFADDEN. 2001. Three-toed browsing horseAnchithenum clarencei from the early Miocene (Hemingfordian) Thomas Farm. Florida. Bull. Florida Mus
Nat. Hist 43(3):79-109.



80 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 43(3)

INTRODUCTION C. Herbel, South Dakota School of Mines, Rapid City, SD;
Thomas Farm is one ofthe best known Tertiary fossil R. M. Hunt, Jr., Nebraska State Museum, Lincoln, NE; C.

mammal sites in eastern North America. Located in R. Schaff, Museum of Compartive Zoology, Harvard
University; and R. H. Tedford, American Museum of NaturalGilchrist County, northern Florida, it preserves an
History, N.Y. I also appreciate the guidance and discussions

exceedingly rich sink-hole accumulation ofearly Miocene that I have had about this study with L. B. Albright III, R.
(early Hemingfordian) land mammals (Pratt 1990). This M. Hunt, Jr., J. O'Sullivan, and R. H. Tedford. I thank E.
locality is about 18 million years old based on correlations Simons for her assistance with the Pony Express program,
with similar sites in the western interior (Tedford et al. curation of relevant specimens, her excellent photographic
1987). Since its discovery in 1931, Thomas Farm has work, and other assistance with the research done during this
produced literally tens ofthousands ofcatalogable fossil study. I extend my thanks to all the Pony Express diggers who
vertebrate bones and teeth, ofwhich about 80 percent of have collected fossil horses from Thomas Farm during the
the macrofauna represent fossil horses. Although there 1990s, including those who foundAnchitherium specimens.

have been different opinions about the number of equid D. Johnson prepared the line drawings ofthe fossil specimens.
V. Bravo kindly translated the Abstract into Spanish. R. C.species and their proper taxonmic names (e.g., compare
Hulbert provided a helpful review that significantly improved

Simpson 1932; White 1942; Bader 1956), as currently the manuscript. This research was supported by National
envisioned, Thomas Farm horses (Family Equidae) Science Foundation research grant IBN-9528020 and the
include three valid taxa, i . e ., Parahippus leonensis Pony Express and Vertebrate Paleontology funds of the
Sellards 1916, Archaeohippus blackbergi (Hay 1924), University ofFlorida Foundation . This is University ofFlorida
and Anchitherium clarencei Simpson 1932. As a rough Contribution to Paleobiology number 489.
qualitative approximation based on specimens collected
during the 1990s, the medium-sized three-toed P HISTORY AND NONEMCLATURE OF
leonensis is very common (representing -90% of the ANCHITHERIUMMEYER 1844 and
equid fossils from this site), whereas the tiny three-toed KALOBATIPPUS OSBORN 1915
A. blackbeqi is uncommon (-9 percent) and the three- An understanding ofthe nomenclature and taxonomy
toed browser A. clarencei is very rare (< 1 percent). ofAnchitherium clarencei from Thomas Farm spans two

Parahippus leonensis has been the subject of continents and two centuries of paleontological
numerous studies, including systematics (White 1942; investigations. I will concentrate here primarily onNorth
Bader 1956; Forsten 1975; Hulbert and MacFadden American material and only highlight selected studies of
1991), taphonomy (Pratt 1990), and population relevant Old World Anchitherium.
dynamics*aleoecology (Hulbert 1984). Because of its In the middle of the nineteenth century the German
rarity, Archaeohippus blackbergi from Thomas Farm is paleontologist Meyer ( 1844) erected the name
less well studied (e.g., Simpson 1932 as A. "nanus"; Anchitherium (anchi-, Gr. near, probably in reference to
White 1942; Bader 1956; Forsten 1975) and this species near the ancestry of modern horses; -therium, Gr. beast)
is currently the subject of a Ph. D. dissertation by UF for early Miocene, low-crowned (brachyodont), three-
zoology student Jay O'Sullivan. The purpose ofthis paper toed fossil horse remains from western Europe. The type
is to describe the hypodigm of Thomas Farm species ofAnchitherium, A. ezquerrae Meyer 1844, was
Anchitherium clarencei and to discuss the question of collected from Cerro de Isidro, Madrid, Spain (Abusch-
the validity of the extinct equid genera Anchitherium Siewert 1983; Sinchez et al. 1998). Leidy (e.g., 1869;
Meyer 1844 and Kalobanppus Osborn 1915. Simpson 1873) assigned remains of middle Tertiary fossil horses
(1932) and White (1942) represent the only detailed from numerous, widespread North American localities
descriptions of Thomas Farm Anchitherium and these (e.g., Texas, Nebraska, and Oregon) to Anchitherium,
were published more than a half-century ago. Within the and in so doing, implied a Holarctic distribution for this
past two decades, renewed excavations have yielded more genus. In one ofthe classic monographs on Anchitherium,
material, particularly of the lesser-known and/or the Russian paleontologist Kowalevsky (1873) did a
previously undescribed postranial elements. Thus, a better brilliant study ofthe anatomy and phylogeny ofthis genus
understanding ofthis very rare horse is now possible. based on specimens from Europe. Of relevance to this

study, Kowalevsky also tacitly accepted a Holarctic
ACKNOWLEDGMENTS distribution for Anchithenum by referencing the presence

I thank the following persons for allowing me to study (as described by Leidy 1869) of this genus in North
relevant equid specimens in their collections; R Bjork and America.



MacFADDEN: Three-toed browsing horse Anchitherium c/arencei from Early Miocene (Hemingfordian) Thomas Farm, Florida 81

Osborn ( 1915) erected the genus Kalobatippus relative to K praestans, K. agatensis is larger and has
(kalobamon- Gr., walking on stilts, in reference to gracile relatively more elongated metapodials.
metapodials; -(11)ippus-Gr., horse) and used as the type Hay (1924) described the new species Miohippus
species Anchitherium praestans (Cope 1879) from the navasotae based on a small sample of isolated anchithere
early Miocene John Day basin of Oregon (Fig. 1). He teeth from early Hemingfordian Garvin Gully Fauna,
described this new genus as follows (Osborn, 1915, plate located about 8 km SE ofNavasota in the Miocene Texas
CVIII): "Upper molars with metaloph united to ectoloph GulfCoastal Plain. In addition to an overall complex of
as in Anchitherium, but M3 and heel of m3 unreduced primitive equid dental characters, Hay (1924) mentioned
and like Miohippus in pattern. Limb bones and that the upper molar contains some cement and a faint
metapodials much elongated, lateral digits unreduced crochet. Ifthis were the case, then this should probably
fromMiohippus stage; phalanges short, inner cuneiform be more properly referred to a parahippine. However,
of pes abutting upon cannon-bone." Osborn (1918, p. the illustrations provided in his paper (Hay, 1924, plate
69) further elaborated upon the description of I) indicate that these characters are poorly represented.
Kalobanppus, with the emended description to include Because of its direct relevance to the present study, the
the following: importance of this species is further discussed in the

context of Forsten's (1975) study ofTexas Gulf Coastal1. Metaloph united to ectoloph (as in Anchither-
Plam horses, as described below.ium, Hypohippus, and Archaeohippus)

In his description of "Anchitherium" agatense from2. Anterior margin of orbit above posterior end of lateral equivalents of the type locality (Agate SpringsM3, as in Archaeohippus.
National Monument) in the Harrison Formation ofNW3. Size exceeding that ofany ofthe known species
Nebraska and adjacent Wyoming, Romer (1926) providedof Miohippus and Archaeohippus.
a thorough and excellent review of the validity of the4. Teeth more brachyodont than in Anchitherium.
genus Kalobatippus. Of Osborn's (1918) fifteen points5. No internal cingulum.
(listed above), Romer concluded that only one (# 12),6. Protolophs of molars and metalophs of P3-4 i.e., metapodial length, served to differentiate these twoincomplete.
genera. In view of the known metapodial variation of7. Last upper molar, and heel of m3 unreduced.
other recognized equid genera (e.g., he citesMesohippus8. No crochet.
and Miohippush Romer concluded that this character9. Incisor row broadly rounded.
also was insufficent for recognition ofboth Anchitherium10. Lachrymal fossa shallow.
and Kalobat*us and hence they were synonymous. In11. Malar fossa broad and not very deep.
the same year Matthew (1926) published a synthetic12. Hind foot with elongate metatarsals and short
review of fossil Equidae. In his Fig. 25 (p. 167) hephalanges; foot longer and more slender than
graphically indicated the distribution of Kalobatippusin Anchitherium or Hypohippus.
as North American, whereas Anchithenum was restricted13. Lateral digits not more reduced than in Anchi-
to the Old World.therium.

Simpson ( 1932) described Anchitherium clarencei14. Metatarsal III-cuboid facet strong.
from the Midway Local Fauna of the eastern Florida15. Metatarsal III with strong meso-entocuneiform
panhandle. In his discussion of the nomenclature andfacet, as in Anchitherium and Hypohippus.
phylogenetic position of this species, he says that the

In this same monograph Osborn (1918) proposed available "characters place it at once as in the
the species Kalobatippus agatensis from the late anchitheriine line and, in the American fauna, closest
Arikareean of Nebraska. As also demonstrated in the either to Kalobatippus or to the earlier and more primitive
type material of K praestans , represented by an species ofHypohippus . It is very difficult to draw a good
associated skeleton, both species clearly have the generic distinction between these two groups, or between
diagnostic characters of the genus, including, in either one and the European genus Anchitherium....I
particular, the relatively unreduced m3 heel and very would prefer to place all the species of Kalobatippus
elongated metapodials (Fig. 2). Comparison of the and the earlier species of Hypohippus in the genus
holotype of K praestans (AMNH 7269) with that of K Anchitherium, to which the present form would then
agatensis (AMNH 14211 ) indicates character differences obviously be referable" (p . 33).
sufficent tojustify these two distinct species. In particular, Ofdirect relevance to the present study, White (1942)



82 
BUT TRTIN FLORIDA MUSEUM NATURAL HISTORY VOL. 43(3)

O.WS

JDO

IFH
GHO A

m BP
CC# PF

QA

SV

WC
Legend:
Ka/obatippus O MW ITF
Anchitherium ~ GGI

Arikareean (Open)
Hemingfordian (Black)
Barstovian (Shaded)

Figure 1. Map of localities discussed in text; BP, Bridgeport, NE; CQ, Clay Quarry, CO; FH, Flint Hills, SD; GG, Garvin Gully, TX;
GH, Goshen Hole, WY; JD, John Day, OR; MW, Midway, FL; PF, Pollack Farm, DE; QA, Martin Canyon Quarry 4 CO; SC, Sioux
County, NE; SV, Sespe-Vaqueros formations, CA. TF, Thomas Farm, FL; WC, Willachoochee Creek, FL; WS, Warm Springs, OR.



MacFADDEN: Three-toed browsing horse Anchitherium clarencei from Early Miocene (Hemingfordian) Thomas Farm, Florida 83

1
45 ~

4

7

1.a

4& 2
4

6a

e .
a

6b

6.C

- Sa -.1-U

Figure 2. Original figure (modified) illustrating holotype ofKalobatippuspraestans, AMNH 7269, from the
John Day Fossil Beds, OR (from Osborn, in Cope 1915, plate CVIII). Note, in particular, the reduced m3 heel
("2," see arrow) and slender metapodials ("6" and "6a").



84 BULLETnN FLORIDA MUSEUM NATURAL HISTORY VOL. 43(3)

described ajuvenile mandible ofAnchitherium cim'encei tinct species. On a related subject, Forsten (1975) noted
from the the middle Miocene Thomas Farm Local Fauna. that in several characters, including the reduction ofthe
He thus followed Simpson's ( 1932) generic and specific M3/m3 , A . clarencei from Thomas Farm is more
assignments and added another locality to the known advanced than Kalobatippus and resembles Hypohippus
distribution ofthis species. and Old World Anchitherium. This is corroborated by

Schlaijker (1935) described a new species of small ideas presented here (also see Hulbert 1993), where A.
equid, Hypohippus avus, from the early Miocene of clarencei from Florida possesses shared-derived char-
Goshen County, Wyoming. The holotype (MCZ 2811) acters that separate it from more primitive Kobatippus
represents a beautifully preservedjuvenile skull with M2 and ally it with Hypohippus and Old WorldAnchitherium.
erupting. No other referred material is known from this Bryant (1991) described two specimens, including a
locality. Some undescribed specimens in the AMNH Lp2 (UF 114723) and partial left P3-Ml (UF 118529),
(F:AM collection) from the Keeline locality ofNiobrara ofAnchitherium clarencei from the Willacoochee Creek
County, Wyoming, which are believed to be referable to Fauna from the Torreya Formation in the eastern Florida
the Harrison Formation (Hunt, pers. comm. 2000), are panhandle, ca. 20 km to the NW of the type locality for
probably referable to this species (MacFadden, pers. this species. This occurrence extends the biostratigraphic
observ. 1999). range ofA. clarenci into the early Barstovian. As such,

Wehrli (1938) presented a detailed description of the temporal duration of this species in Florida is from
Anchitherium aurelianense from 35 localities in about 18 to 15 . 5 (MacFadden et al . 1991 ).
southwestern Germany and Switzerland and also Recent studies considerably extend the known
discussed the supposed distinction between Kalobatippus geographic range, as well as further resolve the bio-
and Anchitherium. Like Romer (1926), Wehrli (1938) chronology, of Anchitherium in North America. Emry
addressed each of Osborn's (1918) fifteen points and also and Eshelman (1998) reportA. sp. from the Pollock Farm
concluded that the variation between these two genera Local Fauna of Delaware, which contains a diagnostic
was also seen within European Anchitherium. He there- early Hemingfordian assemblage (including the horses
fore concluded that Kalobatippus was synonymous with Parahippus leonensis and Archaeohippus blackbergi)
Anchitherium. Stirton (1940), in his classic "Phylogeny and is calibrated by a Sr-isotope age of 17.9 i 0.5 Ma
of the North American Equidae," listed seven species of on interbedded mollusk shells. Donohoo and Prothero
Anchithenum and did not mention the genus Kalobatippus. (1999) described a new early Hemingfordian fauna from

In her review of Gulf Coastal Plain horses from the the Sespe and Vaqueros formations of northern Orange
Miocene ofTexas, Forsten ( 1975) makes Anchitherium County, California . This local fauna is constrained
navasotae (Hay 1924) and A. clarencei Simpson 1932 paleomagnetically between 17-19 Myr and is reported
synonymous. This decision obviously has implications to contain A. clarencei (Prothero, pers. comm. 1999).
for the Thomas Farm sample because A. clarencei would Dingus (1990) reports fragmentary teeth ofknchitherium
therefore be rendered a junior synonym. More recent from the late Arikareean to Hemingfordian John Day
workers (e.g., Hulbert 1993), however, have not followed Formation near Warm Springs, Oregon.
Forsten's (1975) synonymy. This distinctness of these In an overview ofNorth American Equidae, Evander
two species is likewise followed here for the following (1989) considered both Anchitherium and Kalobat*pus
reasons: (1) as Forsten (1975) noted, the mean length of to be distinct and valid, although he did not discuss the
the p3-m2 ofthe Garvin Gully Anchitherium is less than geographic distribution ofthese two genera. Interestingly,
those from Florida; (2) the m3 in the type specimen ofA. his cladistic analysis related Anchitherium toHypoh,ppus
navasotae is not reduced as is the same tooth in the sample and Megahippus, whereas it placed Kalobatipus with
referred to A. clarencei from Florida. It is, however, noted the more derived Equinae. More recently, MacFadden
that this decision is based on small samples that are not ( 1992, 1998) used Kalobatippus as theNorth American
amenable to statistical analysis. If in the future more genus and did not mention Anchitherium as being valid
specimens referred to these species from both Texas and in North America. Given the diversity of opinions that
Florida became available, then it would be important to have been presented over the years, the validity and
further test discrimination ofthese two species . But, with distribution of Anchitherium and Kalobatippus have
the presently available evidence, A. navasotae (Hay) 1942 remained unresolved. The currentstudy sheds additional
andA. clarencei Simpson 1932 areconsidered tobedis- light on this subject .



MacFADDEN: Three-toed browsing horse Anchitherium clarencei from Early Miocene (Hemingfordian) Thomas Farm, Florida 85

MATERIALS, METHODS, TERMINOLOGY, molars); E, early adult (molars erupted and in early
AND ABBREVIATIONS wear); M, adult (all teeth in middle wear); L, late

Relevant fossil materials of anchithere horses were wear (all teeth heavily worn).
studied from the following museum collections (acronyms P 1 M 3 T R L ( o r p lm3trl); tooth row length from anterior-
are used in the text): most part of DP 1 (or dp 1 ) to posteriormost part of
AMNH; Depaknent of Vertebrate Paleontology, The Amen- M3 (or M3).

can Museum ofNatural History, New York City. P2M3TRL (or p2m3trl); tooth row length from anterior-
F:AM; Frick:American Mammals, part of the AMNH most part ofP1 (orpl)toposteriormost part ofM3 (or

collection. M3); = measurement 9 ofEisenmann et al. (1988, p. 7).
MCZ; Museum of Comparative Zoology, Harvard Upper dentitions (Fig. 3)

University, Cambridge, Massachusetts. APL; greatest anteroposterior length of Ml, M2, or M3;
UF/FGS; Florida Geological Survey Collection, now part =measurement C2 of Eisenmann etal. (1988, p. 23).

of UF (see below). TRN; greatest transverse width of Ml, M2, or M3; =
UF; Vertebrate Paleontology Collection, Florida Museum measurement C4 of Eisenmann et al. (1988, p. 23).

ofNatural History, University ofFlorida, Gainesville. MSTHT; mesostyle height ofenamel, excludes specimens
The following other abbreviations and terminology for ONT = L (late wear).

are used in the text: CROCHET; crochet development; P=present, R=
Anchithere; an adjective or noun used to describe the rudimentary, or A=Absent (not illustrated in Fig. 3).

polyphyletic, horizontal assemblage of low-crowned RIBS; P=present; R=rudimentary; or A=absent (not
late Oligocene-Miocene horse species traditionally illustrated in Fig. 3).
assigned to either advanced Miohippus, CINGULUM; internal (lingual) cingulum, P=present, R=
Kalobatippus, Anchitherium, Sinohippus, . rudimentary, or A=absent (not illustrated in Fig. 3).
Hypohippus, or Megahippus. This is obviously not Lower dentitions (Fig. 3)
a strict phylogenetic category. apl; greatest anteroposterior length; = measurement C2

L; left side. of Eisenmann et al. (1988, p. 29).
L.F., Local Fauna; a geographically and temporally trn; greatest transverse width; = measurement C6 of

restricted fossil assemblage Eisenmann et al. (1988, p. 29).
M, m; molar (upper, lower) mtcmstht; metastylid/metaconid height of enamel,
Ma; megannum, in reference to a point, in millions of excludes specimens for ONT = L (late wear).

years, on the geological time scale m3heel; greatest anteroposterior length of hypoconulid
Myr; million years ago on the geological time scale, heel ofm3 (see Fig. 4).

usually in reference to a duration or span of time. m3ratio; mapUm3heel, an indication ofthe relative size
P, p; premolar (upper, lower). ofthe hypoconulid heel on m3.
R; right side. Metatarsal III (Fig. 3)

Dental terminology follows the convention of upper The metatarsal (MI) was chosen to charaterize the
case for upper teeth (i.e., I, C, P, M) and lower case for general morphology, size-related limb parameters, and
lower teeth (i.e., i, c, p, m). Anatomical terminology relative limb robustness because: (1) the only complete
generally follows Getty (1975) and dental terminology metapodials for Thomas Farm Anchitherium are
follows Stirton (1941) and MacFadden (1984). Many of represented by MT III; and  fortunately, (2) the associated
the measurements presented here follow the conventions limb bones for relevant type specimens ofclosely related
of Eisenmann et al. (1988). species also include MT III. Measured characters and

During this study a database was developed that for ratios used here are as follows:
every specimen included the following possible suite of PRXW; greatest transverse (mediolateral) width across
coded variables or measurements: proximal articular surface; = measurement B3 of
Generah-tooth row and ontogeny Eisenmann et al. (1988, p. 61).
U/1; Upper or lower tooth. GRTL; greatest proximodistal length; = measurement C 1
SIDE; right or left, of Eisenmann et al. (1988, p. 61).
ONT; ontogenetic stage as asiessed fromteeth; J, juvenile MDSH; midshaft mediolateral width; = measurement B3

(deciduous premolars and/or incompletely erupted of Eisenmann et al. (1988, p. 61)



86 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 43(3)

ri
 E 1-*PRxw~

r-2 - - la

» f\ 5 3* 'I

012 11
tI i cm

MDSH'=

G
RTL

CD j
1, 4j illi5-15

--

-czzz apl - ~ DSTB~ 4 ff <*

<DSAR.

Figure 3. Dental and MT II[ measurements and abbreviations (also see text). Upper molar, occlusal (A) and external
(B) views. Lower molar, occlusal (C) and internal (D) views. MTIII measured characters (ID.

DSTB; transverse (mediolateral) width across distal worn maximum MSTHr or mtcmstht ca. 10 to 14 mm.
tuberosities; = measurement B10 of Eisenmann et Preorbital facial fossa large, oval, and moderately well
al. (1988, p. 61). developed excavated depression on maxillary, nasal, and

DSAL greatest transverse (mediolateral) width across lacrimal bones, but lacking a well defined rim or
distal articular trochlea; = measurement Dll of pocketing. Anteriormost part of orbit lying above M3.
Eisenmann et al. (1988, p. 61). Upper and lower cheek teeth with cingula moderately

INDEX; metatarsal index of robustness (=GRTL/ developed, rudimentary, or absent. Upper cheek teeth
MDSH; not illustrated in Fig. 3). lacking cement and crochet, ribs poorly developed,
All coded variables and measurements were analyzed metaloph and protoloph connected to ectoloph except in

using SAS (Statistical Analysis System; SAS Institute, unworn or little-worn teeth. M3 reduced relative to M2.
1985) provided on the University of Florida mainframe Lower teeth with moderately separated metaconi(Is and
computer (NERDC, Northeastern Regional Data Center). metastylids, m3 with characteristically reduced

hypoconulid heel which does not come into wear until
SYSTEMATIC PALEONTOLOGY late maturity. Metapodials ca. 230 mm to 255 mm long

Class Mammalia Linnaeus, 1758 and robust (mean metatarsal INDEX = 10.0; see Table
Order Perissodactyla Owen, 1848 1). Well developed facets for cuboid and mesento-

Family Equidae Gray, 1821 cuneiform on MI' III. Lateral metapodials relatively well
Genus Anchitherium Meyer, 1844 developed in contrast to later equids, e.g., Parahippus.

Generic diagnosis.-Moderately large, brachyo- Proximal phalanges not elongated.
dont, anchitheriinetridactyl horse. DPl/dpl-M3/m3 tooth Anchitherium differs from Kalobatippus in having
row lengths ca. 120 mmto 135 mm; P2*2-M3/m3 tooth more reduced m3 hypoconulid heels and longer, broader
row lengths ca. 113 mmto 127 mm. MlAPL, M2APL, (in mid-section), and more robust metapodials;
mlapl, or m2apl ca. 19 mm to 22 mm. Unworn or little- Anchitherium differs fromMiohippus andMesohippus



Table 1. Dental and metatarsal III measurements for Anchitherium and Kalobatippus based on specimens examined during this study. These two genera were
sorted into a priori groups based on qualitative differences (described in the text) that are frequently used to distinguish these two genera. For abbreviations,
see text and Fig. 3.

Character Taxon N, x, s, range Taxon N, x, s, rangel Probability Different?2

P1M3TRU Anchitherium 9, 128 . 8, 7 . 0, 116 . 8- 140 . 6 Kalobatippus 6, 117 . 6, 7 . 9 , 109 . 3 - 128 . 9 0 .012 Yes
P2M3TRL3 Anchitherium 17, 120 . 7 , 7 . 6 , 107 . 7- 133 . 7 Kalobatippus 6, 109 . 3 , 8 .7 , 100 . 4- 121 . 2 0 .006 Yes
UlMAPL' Anchitherium 71 , 20 . 8, 2 . 1 , 16 . 2 -25 . 3 Kalobatippus 19, 19 . 4, 2 . 7, 16 . 5 -25 . 9 0 .020 Yes
UMTRN~ Anchitherium 25, 23 . 6, 2 . 2 , 19 . 2-27 . 4 Kalobatippus 6, 20 . 8 , 1 . 2 , 19 . 4-22 . 4 0 .004 Yes
1mtmw' Anchitherium 47, 13 . 4, 1 . 6 , 10 . 1 - 16 . 2 Kalobatippus 13 , 13 . 2, 1 . 7, 10 . 9- 16 . 2 0 .723 No
HEIGHTS Anchitherium 66, 10 . 0, 2 . 2 , 5 . 2 - 16 . 7 Kalobatippus 15, 8. 6, 1 . 0, 6 . 3 - 10 . 2 0 .022 Yes
m3ratio Anchitherium 12, 4 . 4, 0 . 9, 3 . 4-6. 0 Kalobatippus 5 , 3 . 4, 0 . 3 , 3 . 1 -3 . 9 0 .013 Yes
GRTL Anchitherium 22, 243 . 0, 12 . 8 , 216 . 0-264 . 0 Kalobatippus 7, 212 . 6, 20 . 0, 194 . 0-254 . 0 0 .001 Yes
PlUCW Anchitherium 20, 32 . 2 , 2 . 4, 27 . 8-38 . 7 Kalobatippus 7, 24 . 9 , 2 . 5 , 21 . 6-28 . 0 0.000 Yes
MI)SH Anchitherium 24, 24 . 1 , 2 . 2 , 20 . 4-31 . 4 Kalobatippus 7, 17 . 5 , 1 . 4, 15 . 8-20 . 0 0.000 Yes
DSTB Anchitherium 22, 34 . 4 , 2 . 1 , 30 . 6-39 . 7 Kalobatippus 7, 27 . 4, 2 . 2, 24 . 6-31 . 4 0 .000 Yes

M
acFAD

D
EN

: 
Three-toed brow

sing horse Anchitherium
 c/arencei from

 Early M
iocene (H

em
ingfordian) Thom

as Farm
, Florida 

87

DSAR Anchitherium 20, 30 . 4, 1 . 2 , 29 . 0-33 . 4 Kalobatippus 7, 23 . 1 , 2 . 8, 18 . 9-26 . 9 0 .000 Yes
INDEX Anchitherium 22, 10 . 0, 0 . 7, 8 . 4- 11 . 4 Kalobatippus 7, 12 . 1 , 0 . 9, 11 . 1 - 13 . 1 0 .001 Yes

'N, number of specimens measured; x, mean; s, standard deviation; range, i.e., observed minimum to maximum.
2Are Anchitherium versus Kalobatippus different (assuming an acceptable cutoff probability ofp < 0.05) using either the t- or Wilcoxon tests for significance?
All linear measurements were assumed to be normally distributed with equal variances (the latter of which usually resulted in lower probability levels than for
unequal variances) and thus the t-test was used; RAI10 and INDEX are both ratios and thus the non-parametric Wilcoxon test was used.
'Includes both upper and lower dentitions as combined data sets.
4Upper and lower transverse widths analyzed separately.
S HEIGHT = pooled sample ofMSTHT (uppers) and mtcmstht (lowers); Well-worn teeth (ONT = " L") removed from analysis.



88 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 43(3)

in larger size, stronger connection ofthe metaloph to the there were discernable differences between these two taxa,
ectoloph, reduced internal cingula, weaker upper cheek- as had been previously described in the literature. It was,
tooth ribs, better separated metaconids and metastylids, however, unclear which morphological characters would
and more pronounced cuboid and ectocuneiform facets be most important in quantitative discrimination and to
on MT III; Anchitherium differs from Hypohippus in what extent these differences might be related to size
being less hypsodont and having faint ribs in the upper (Kalobatippus is generally a smaller horse than Anchi-
cheek teeth (they are absent in the latter genus), relatively therium).Results of t-tests of all five metapodial
more pronounced m3 heel, and preorbital facial fossa characters (GRTL, PRXW, MDSH, DSTB, and DSAR)
lacking either pocketing or well defined rim, and in most indicate that there are statistically significant differences
species smaller size. Anchitherium differs from in all these size-related characters. In addition, a Wilcoxon
Parahippus (including "Desmatippus ") in lacking non-parametric test ofthe metapodial character INDEX,
cement on the cheek teeth and a crochet on the upper pre- which is an indicator of relative robustness, also yielded
molars and molars, and having less elongated phalanges. statistically significant results (Table 1). These characters

Included North American species.-A. navasotae all indicate that the MT III ofAnchitherium is both larger
(Hay 1924), A. clarencei Simpson 1932, and one or more and relatively more robust than that of Kalobanppus,
undescribed species from the western U.S. (as represented thus confirming the observations ofprevious workers.
in the AMNH collections). There also are dental characters that distinguish

Distribution.-Early Hemingfordian of Delaware, Kalobatippus from Anchitherium, most ofwhich relate
Florida, Texas, High Plains (Nebraska, Colorado, Wyo- to relative size, including toothrow lengths, upper and
ming, South Dakota, and California); late Hemingfordian lower molar lengths (UlMAPL), HEIGHT, and upper
of Florida; possibly late Hemingfordian of California molar transverse width (UMTRN; Table 1). Many
(Fig . 1 ). Tedford et al . ( 1987) stated that the genus workers have indicated that the m3 heel ofAnchitherium
Anchitherium persists in North America through the is reduced relative toKalobanppus (Fig. 4). The character
Barstovian; this is corroborated in Florida (Bryant 1991). m3ratio, which takes into account the relative develop-
While it is indeed true that other anchitheres are found ment ofthe m3 heel, is statistically significant (p = 0.013,
elsewhere in North America during the Barstovian (16.5 assuming a cut-off ofp < 0.05). In summary, there are
to 11.5 Myr; MacFadden, pers. observ. 1999), theexact quantitative characters of the MT III and dentition that
biochronological range of Anchitherium s. s. in North serve to differentiate Anchithenum from Kalobatippus.
America must await a comprehensive analysis of all
Miocene anchithere horses on this continent. Anqhitherium clarencei Simpson, 1932Discussion.-Stirton (1940) listed seven species
assignable to North American Anchitherium sensu lato. Type specimen.-UF/FGS V-5074, R Ml -M3 ,
As currently envisioned, ofthese seven, three are referable Midway L. F., Gadsden County, FL. (Also see other
to Kalobatippus as K. praestans (Cope 1819) G K. referred specimens from the Midway locality in Simpson
gracihs Marsh 1892), K avus (Schlaikjer 1935), and [19321). The holotype, which is an adult dentition in
K agatensis Osborn 1918, whereas Anchitherium middle wear (Fig. 5), preserves diagnostic and important
includes A. navasome, A. clarencei, and one or more characters represented in this species, including weakly
new, undescribed species from western North America. developed ribs on ectoloph, both protoloph and metaloph

In many respects Kalobatippus and Anchitherium connected to ectoloph, rudimentary internal cingulum,
are very similar and hence the confusion about the validity triangular hypostyle connected to metaloph, M3 (APL =
ofthese two genera, particularly in North America. Most 16.7 mm, TRN = 21.4 mm) smaller than M2 (APL =
workers who have considered Kalobanppus to be distinct 21.5 mm, TRN=24.3 mm), and brachyodont teeth (Ml
from Anchitherium have focused on the metapodial MSTHT = 7 . 7 mm, M2 MSTHT = 8 , 5 mm, M3 MSTHT
proportions, principally the relative robustness of MT = 7.8 mm; also see Table 2).
III. This important, defining character has heretofore not Referred material from Thomas Farm.-Cranial
been analyzed statistically, mostly due to the paucity of anddental: MCZ 19930, flattened but relatively complete
relevant specimens. During this study all available MT skull of mature adult with R and L Il, 12, R and & Pl-
IIIs were measured for Kalobatippus and Anchitherium M3 ; UF/FGS V-5243 , right mandible with p2-m3 (also
(Table 1). Upon examination and in a qualitative sense, see Simpson 1932); UF 17615, L mandibular fragment



MacFADDEN: Three-toed browsing horse Anchitherium clarencei from Early Miocenc (Hemingfordian) Thomas Farm, Florida 89

with p2, p3, fragmentary p4; MCZ 3810, L mandible ~-11>-0.'with ascending ramus, dp2-dp4, ml erupting (also see
'.\White 1942); UF 19756, L mandible with ascendmg ./ 2 - NO.9407 Type

ramus, dp2-dp4, ml erupting; MCZ 7595 , L dP2 ; UF A. M.

156492, UF 164050, 164051, isolated incisors; UF Hypohippus 0360rni
156492 L occipital condyle.

Axial skeleton: UF 171842, 181198, fragmentary
cervical vertebra. ~Forelimb: MCZ 7626,2 L scapulae; MCZ 7598, L
scapula, MCZ 7600, Rhumerus , UF 1473 , 200364 distal NO. lal;~. ellrt' rlf.

Rhumerus; UF 172615, 174950, R radius; MCZ 7601, Anchitkerium aurelianense

L radius; UF 44720, distal L radius; MCZ 7633, L ulna;
MCZ 7603, L scaphoid; UF 19843, L lunar
(intermediate); MCZ 7459, R pisiform; UF 190343, R
proximal MC II; UF 45507, L proximal MC III.

\51 - No./42// 1Ppe <ren
Hindlimb: UF 174127, L innominate; UF 1325 , A. M.

fragment proximal L femur; UF 177675, fragment distal Kalobat*pus agatensis
L femur; UF 1437, R patella; UF/FGS V-6595, MCZ
759, UF 43625, L astragalus; MCZ 7599, UF 157922, --
R calcaneum; MCZ 7458, L calcaneum; UF 43601,
44724, L navicular; UF 155689, 58605, R ~~.72697*,•A. M.
ectocuneiform; UF 60717, 182749, L ectocuneiform;UF Kalo6atippus prfestans66944, 204045, R cuboid; MCZ 7608 (2 specimens),
UF 155081, R MT III; UF/FGS V-6748, proximal R
MT III; UF 47569, proximal L MT III.

Miscellaneous podial elements, UFfFGS V-5301,
--=------ ---~- --=' No.726# TypeV-6592, fragments of distal articular surface of A. M.

metapodial III; UF 58782, 175395, proximal phalanx of Miohippus eguiceps
medial digit III; UF 47450, 98400, 175396,2nd (medial)
phalanx of medial digit III; UF 203700, 204948, distal Figure 4. Left m3s ofselected anchithere horses showing
(ungual) phalanx of medial digit III; UF/FGS V-5273, the development of the posterior heel (right). In the
fragment of lateral metapodial with distal articular primitive condition, as seen for example in Miohippus
surface; UF/FGS V-6593 , UF 19985 , 43624, 164118, equiceps (bottom, which includes m2and m3), the heel
172006, MCZ 7605 and uncataloged; proximal phalanx is relatively well developed. In the advanced condition,
of lateral digits (II or IV); UF/FGS V- 10077, UF 59091 , as seen for example in Hypohippus osborni (top), the
161068, 165150, 165914, 196874, MCZ uncataloged heel is relatively reduced and usually does not form part
(6); medial phalanx of lateral digits (II or IV); UF 19833, ofthe occlusal surface ofthe tooth until late wear. Taken
19839, 47571, 204949, ungual (distal) phalanx oflateral from Osborn (1918, plate 5). Natural size.
metapodial; UF 1418, 165811, 180631, 183658, 183294,
183603, 185254, 195643, sesamoids.

Geographic location.-early Hemingfordian (18
Ma) to early Barstovian (-15.5 Ma) of Florida, early on the nasal, lacrimal, and maxillary bones, malar fossa
Hemingfordian Flint Hill L.F., South Dakota, and poss- absent, rounded incisor arcade; teeth brachyodont;
ibly early Hemingfordian Sespe and Vaqueros formations, moderately large horse, similar in size to modern donkey
California; possibly also from Frick (AMNH) Clay (Equus asinus), mean P1M3TRL = 125 . 3 mm ;
Quarry and Martin Canyon Quarry A, Colorado. P2M3TRL = 117.5 mm. Upper cheek teeth with well

Revised Diagnosis.-Same as for the genus, with developed styles in the molars; relatively large dPl, cement
the following specific complex ofcharacters: elongated absent, no crochet, metaloph connects to the ectoloph;
cranium, preorbital facial fossa shallow and developed internal cingula well developed on the upper premolars,



90 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 43(3)

the skull indicates a relatively large horse, with a greatest
skulllength of-373 mm and a condylar-basal skull length
of -342 mm (both measurements are approximate
because of postmortem distortion). This size is similar
to a modern donkey, Equus asinus (UF 156889), con-
tained in the UF VP collection. The upper incisor arcade
is rounded and the incisors (R and L Il and I2 preserved)

FS. V-5074 have cups (infundibula). The precanine diastema (R =
15.0 mm, L = 14.4 mm; from posteriormost part of I3
alvoeli to anteriormost part of C alvoeli) is shorter than
the postcanine diastema (R = 32.7 mm; L = 29.0 mm;
from posteriormost part of C alvoeli to anteriormost part

xvi--/laK\-0" Bt=~liv,'#19 ofP 1). The nasal notch, which lies anterodorsal to dPl,
is unretracted relative to the condition seen in advanced,

- later Cenozoic equids. Although located in a badly
crushed region, the infraorbital foramen (IOF) appears

Figure 5 . Holotype ofAnchitherium clarencei , UF/FGS to lie dorsal to the posterior half of P3 . The anterior
V-5074, R Ml-M3, from the Midway L. F., Gadsden margin ofthe orbit lies dorsal to the junction of Ml and
County, Florida, external (top) and occlusal (bottom) M2. The cheek region (not illustrated) is dorsoventrally
views. From Simpson (1932, p. 32, Fig. 18). Natural crushed, but indicates a shallow, large, dorsally positioned
size. preorbital facial fossa lacking either a distinctive rim or

posterior pocket. There does not appear to be a ventrally
positioned malar fossa. The maximum transverse width
across the occipital condyles is 54.2 mm.

moderately developed or rudimentary on the molars; In the upper cheek teeth the dP 1, which is retained
mean Ml/M2 APL=20.8 mm; mean M1/M2 TRNW = in adult dentition, is anteroposteriorly longer than its
23.3 mm; MSTHT/mtcmstht = 9.6 mm (Table 2). transverse width; lingually there is a well delevoped

Mandible shallow (mean depth beneath posterior part cingulum; the labial halfofthe tooth is in occlusal wear.
of m3 E 53 mm); internal cingula poorly developed The anterostyle of P2 is well developed. The internal
relative to upper premolars; well developed and distinct cingulum is relatively well developed on the premolars
metaconids and metastylids, ml/m2trnw = 13.gnun; and poorly developed or absent onthe molars. The dental
m3 hypoconulid heel reduced and is not part ofthe occlusal pattern ofP2 through M3 is similar, with a well developed
surface until late wear. MT III short relative to other W-shaped ectoloph with high crests indicating transverse
Anchitherium (mean GRIL = 218.7 mm) but relatively shear; the protoloph and metaloph are well developed,
more robust than Kalobanppus (mean INDEX = 9.8, N = lack proto- or metaconules or crochets, and are connected
3, s = 0.3 mm, observed range = 216 to 222 mm). to the ectoloph (Fig. 7). Ribs on the ectoloph between
Proximal phalanges of MT III relatively unreduced. the styles vary from rudimentary to moderately developed.

Anchitherium clarencei differs from the closely A prominent hypostyle is located in the posterior portion
related species A. navasome because the former is slightly ofthe cheek teeth. As Simpson (1932, p. 32) described,
larger in size and has a more advanced reduction of the the hypostyles for A. clarencei are "triangular, circular,
m3 hypoconulid heel. pitted, united by crest to hypocone." The M3 is smaller

Description.-Although there have been previous than either the M 1 or M2 (Table 2). There are very strong
descriptions ofthe morphology ofAnchitherium clarencei and well developed external cingula that extend upward
from Thomas Farm, recent collecting and integration of on the teeth to form the parastyles and mesostyles. The
the hypodigm from the UK FGS, and MCZ collections mesostyle crown heights are brachyodont (with
warrants further description here. hypsodonty index [MSTHr/APL] of<< 1) and higher

Cranium anddentition. A single crushed skull, MCZ crowned relative to primitive horses such as Miohippus,
19930, ofA. clarencei is known from Thomas Farm (Fig. but shorter than Hypoh*pus and more advanced forms
6). In contrast to other middle Miocene horses (e.g., like Parahippus (also compare with MacFadden 1992,
Parahippus leonensis and Archaeohippus blackbergi), p . 240, Fig . 11 . 6).



Table 2. Cheek tooth,(22 or p2/4«ough M3 or m3) measurements of Anchitherium clarencei from Florida. For each entry, the sequence r#resents APL or:apt, TRW %
& trn, and MST*r *r.mtcm*tht. See ted'for abbreviations.
Specimen no. Locality Position P2*2 P343 P411'4 Ml/ml Ml/mt MB/inj m3*def
UF/EGS V5074 type Midway RU 22.0,23.0,7.7 21,5,24.3,8.-5 16.7, 21.4,7.8
MCZ 19934 Thomas Farm RU 24.7,20.3,7.4 21.4,26.3,8.6 20.9,24.8,8.7 21.3,23.3,8.8 20.0,22.5,8.21 18.1,20.8, 7.2 7.2
UF/FGS V5243b Thomas Farm Rl 20.9, 11.4, 9.1 20.4, 12.7, 10.2 20.7, 14.6, 10.4 21.1, 14.2, 11.3 20.0, 13.2, 11.8 24,0,11.4,«10.8 6.2
MCZ 3810 Thommq Farm Ll 22.0,12.1,6.1 19.7,14.4,7.2 21.6,13.4,7.5 20.0,13.9,11.0 20.0,12.7, - - -

UF 176159 ThomasfFarm LL 20.5, 12.8, 9.0 20.0, 15.6, 10.4 20.0, 15.6, 10.4 - - - -
AMNH 22684 Midway Ll - - - 23.4,11.0,8.9 5.3

UF 118529 Willacoochee LU 21.2, 22.2, 7.1 19.6, 22.3, 7.3 19.7, 21.4 5.5 - - -
UF lj14723 Willacoochee Ll 21.0,11.9,9.3

Three-toed browsing horse Anchitherium
 clarencei from

 Early M
iocene. (H

em
ingfordian) Thom

as Farm

*P1M3*R-Lf= 12~:2;~2MBTRL,= 115.2.
bj,lmjtrl -3 126.j; pi#3*1=., 119iS.
°Dedduous premolar:series (not'used in statistics presented in Table 1).

$L



92 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 43(3)

/9

024i i i cm

Figure 6. Ventral view of crushed cranium of Anchitherium clarencei, MCZ 19930, from Thomas Farm, early
Hemingfordian of Florida.

As represented inMCZ 3810, the alveoli forthelower lie between, and ventral to, c and pl. The postcanine
symphysial dentition indicate a rounded incisor series. diastema (posteriormost part ofc to anteriormost part of
There is no precanine diastema, as the canine is appressed pl) is 31.6 mm in MCZ 3810 and >40.8 mm in UF
to the i3. On the L side of MCZ 3180 a single mental 17615. With regard to p2-m3, the labial cingulum is
foramen lies about midway between, and ventral to, the poorly developed, whereas the lingual cingulum is strong
canine and pl (Figs. 8,9); on UF 17615 four foramina and well developed. The p2 has a relatively elongated



MacFADDEN: Three-toed browsing horse Anchitherium clarencei from Early Miocene (Hemingfordian) Thomas Farm, Florida 93

A  14<t
-.

R

012

1 1 Icm
ect rib cin

B ant Mr' fVi et +7
. 0

1„Li, *
dJ ff

4# 1,

prt met hyp

Figure 7 . Photograph (A) and line drawing (B) of LPl -M3 of Anchitherium clarencei, MCZ 19930, from Thomas
Farm, early Hemingfordian of Florida. ant, anterostyle. cin, cingulum. ect, ectoloph; hyp, hypostyle; met, metaloph;
prt, protoloph; rib, rib.

and expanded region anterior to a well developed width of 59.9 mm and width across the distal trochlea of
paraconid, a single metaconid/metastylid, and a well 55.6 mm. In general proportions and morphology the
developed metalophid with a well developed entoconid humerus of A . clarencei is distinctly equine, although
posterolingually (Fig. 8). In p3-m3 the protolophids with some notable exceptions (Fig. 10). The deltoid
and metalophids are equal/subequal in size and there are tuberosity is relatively poorly developed and the teres
distinct and relatively well separated metaconids and major tuberosity is absent. The morphology of the
metastylids. The m3 is characterized by a moderately proximal articular surface is different from advanced,
developed hypoconulid heel. In most respects the dental i.e., equine, horses (e.g., Equus). In Equus this region
pattern of Anchitherium clarencei demonstrates a between the greater and lesser trochanters has atrochlear
stage of evolution similar to primitive anchitheriines region with a well developed intermediate tubercule for
such asMiohippus, with the principal difference being accommodation ofthe biceps brachii tendon, which acts
that the former genus is larger in overall size-related as a passive stay apparatus during standing (Hermanson
characters . and MacFadden 1992). In A . clarencei the trochlear

Forelimb. The scapula (not illustrated) contains a region is curved to form a fossa defined by the greater
well developed and rugose olecranon process for and lesser tubercules and the INT is rudimentary (Fig.
attachment of the biceps brachii tendon . The mean 10). In this morphology, A . clarencei is similar to
greatest width (N = 3 ) of the glenoid fossa is 44 . 1 mm . Mesohippus, Merychippus, andextantTapirus terrestris,
On the blade the coracoid process is poorly developed. as illustrated in Hermanson and MacFadden (1992, p.
There is a well developed coracoid crest that is recurved 379-380, Figs. 1,2).
ventrally as it extends the length ofthe scapula. The radius has a mean greatest length of 255 mm

The complete humerus (MCZ 7600) is 225 mm in (N = 2), a mean greatest transverse width (proximal to,
greatest length, with a mediolateral (transverse) proximal and excluding the radial tuberosities) of the proximal



94 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 43(3)

A

B
i

012
LLIcm

C

D

Figure 8. Mandibles ofAnchitherium clanncei from Thomas Farm, occlusal (A, C, ID and external (B, D, F) views,
UF 19756, L mandible with dp2-dp4, ml erupting (top); UF/FGS V-5243, R mandible with p2-m3 (bottom); MCZ
3810, L with dp2-dp4, ml erupting (next page). Note: C and D are reversed.



MacFADDEN: Three-toed browsing horse Anchitherium clarencei from Early Miocene (Hemingfordian) Thomas Farm, Florida 95

E

012

articular surface of 46.0 (N = 4), and a mean greatest The carpus is represented by three bones (not
transverse width (distal to, and excluding) of the distal illustrated). On the antero-internal face of the scaphoid
articular surface of 39.8 mm (N = 2). The shaft of the (MCZ 7603) there are two well developed facets for the
radius is crushed, but the anterior surface is convex and lunar and posteriorly there is a well developed volar
the posterior surface is concave . In life, the radial shaft tuberosity. The lunar ( intermediate) of A. clarencei is
would have been slightly bowed. In general proportions represented byasingle specimen (UF 19843). Other than
and morphology the radius ofA . clarencei is distinctly being relatively less broad transversely relativetothe radial
equine, although with some notable exceptions (Fig. 11). and ulnar bones, in most characters this element resembles
In particular, on the distal articular surface the medial advanced equines. The pisiform (MCZ 7459) is concave
facet for the lunar (intermediate) carpal bone is relatively internally, convex externally, and, relative to Equus, has
small in contrast to its development in advanced equines a very large cuneiform facet and smaller ulnar facet.
such as Equus . This condition in A . clarencei reflects Hindlimb . A partial left pelvis is represented by UF
the lesser development of the central (III) carpal, 174127 (not illustrated; also other specimens in the
metacarpal, and phalanges relative to their lateral (II or MCZ). It has a relatively elongated ilial shaft in contrast
IV) equivalents . to primitive horses like Mesohippus (Hussain, 1975 ).

The ulna (MCZ 7633), although broken distally, The region of the obturator foramen is not preserved.
indicates a shaft that extends more than halfway down A single specimen (UF 177675, not illustrated)
the shaft ofthe radius (Fig. 11). In contrast to the strong preserves the distal articular region of the R femur.
fusion of the ulna and radius in advanced equines (e.g., The greatest transverse width across the medial and
Equus), the ulna of ,4 . clarencei appears to have been laterial condyles (distal to the epicondyles ) is 57 . 4
loosely affixed to the radius. mm. The lateral ridge of the trochlea has a well defined



96 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 43(3)

0 1 2 cm
, k) Ill

4=

jIil Ii· i//,25~-- _I * 16 *3 / -3
2 - 

-1-9-- =*4, 3)))/
1/,

2'FS V-5243

0 1 2 cm
L_1__1 .., * 2,.fI:#

MC Z.3810

-. , .- * + :---- F

Figure 9. Mandibles ofAnchitherium clarencei from Thomas Farm. UF/FGS V-5243 (top),
occlusal and internal views (modified from Simpson 1932, p. 32, Fig. 19). MCZ 3810 (bottom),
external and occlusal views (modified from White 1942, plate 9).

and distinct ridge; the corresponding medial ridge is not described for tridactyl horses. Relative to a similar-sized
preserved. Equus, e.g., a donkey (E. asinus, UF 156889, that was

The calcaneum has a mean greatest length of 92.1 also used for other postcranial comparisons below), the
mm (N = 3) and greatest mean transverse width across tuber calcis in A. clarencei has a more pointed surface
the sustentaculum of 39.9 mm (N = 3). In general (Fig. 12) for articulation with the Achilles tendon. The
morphology the calcaneum is as Hussain (1975) development of the proximat lanceolate facet, which



MacFADDEN: Three-toed browsing horse Anchitherium clarencei from Early Miocene (Hemingfordian) Thomas Farm, Florida 97

ItAbt Cgt

dt
bbt

012
iii cm

Figure 10. Humerus of Anchitherium clanncei (MCZ 7600) from Thomas Farm, anterior
view (A), proximal articular surface (B), and posterior view (C). bbt, fossa for biceps
brachii tendon; dt, deltoid tuberosity; gt, greater tubercle; It, lesser tubercle.

articulates withthe astragalus, deserves some discussion in this character could be used to separate Old and New
here. As reviewed in Hussain (1975), this facet is absent World Anchitherium. In all three specimens of A.
in primitive equids and Old World Palaeotherium, clarencei from Thomas Farm, the proximal lanceolate
rudimentary in Old World Anchitherium, and well facet is either absent, poorly developed, orconfluentwith
developed in New World Anchitherium and advanced the facet ofthe processus cochlearis for articulation with
equines, e.g., Equus. Ifthis were the case, then differences the astragalus. This observation is thus different from



98 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 43(3)

B

Z

012
1 1 Icm

D,

If

Figure 11 . Lower forelimb ofAnchitherium clarencei from Thomas Farm . Anterior view (A) of left radius (MCZ
7601) and ulna (MCZ 7633); extemolateral view (B) of left radius (MCZ 7601) and ulna (MCZ 7633) showing
development ofulnar notch and length of reduced ulnar shaft (distalmost part ofwhich is missing); photo (C) and line
drawing (D) of distal articular surface of radius (MCZ 7601). lf, lunar facet.

that of Hussain (1975). Further analysis of the from the dorsalmost part of the medial trochlear ridge to
distribution ofthe character and its various states in fossil the navicular facet) is 48.5 mm (N =2)and mean greatest
horses is necessary before it warrants the definitive transverse width across the navicular facet is 33.3 mm
phylogenetic significance suggested by Hussain ( 1975) (N = 3 ). All three astragali ofThomas Farm A. clarencei

In the astragalus, the mean greatest length (measured demonstrate similar morphology and relatively little



MacFADDEN: Three-tod browsing horse Anchitherium clarencei from Early Miocene (Hemingfordian) Thomas Farm, Florida 99

A B

,0

C D~

012 =**'0 9

1 Icm Sts M

E F -ps.1»3.
af 1 23 F~. 1.1;f'/

[Ift'*q 3 »~ f af
012

1 I cm

Figure 12. Right calcaneum (UF 157922) of Anchithenum clanncei from Thomas Farm  internolateral (A) and
dorsal (C, E) views as compared to donkey, Equus asinus (UF 156889; B, D, and F). af, astragalar facet; pc,
processus cochlearis facet; plf, proximal lanceolate facet; tc, tuber calcis.

variation in the development of the articular facets. The in Equus (Fig. 13). Kowalevsky (1873) reported that the
medial trochlear ridge contacts, or nearly contacts, the posterolateral calcaneal facet was absent in
navicular facet. As noted by Hussain (1975), the medial Anchitherium. As Hussain (1975) also observed for all
and lateral trochlear ridges in A. clanncei are slightly North American equids, this facet is distinct and well
more inclined relative to the sagittal plane than they are developed in A. clarencei from Thomas Farm (Fig. 13).



100 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 43(3)

A B

1

nf
nf 012

Icm
C D

er %

pcf

pcf

Fig. 13. Left astragalus (MCZ 759) ofAnchitherium clarencei from Thomas Farm dorsal (A) and plantar (C) views
as compared to donkey, Equus asinus (UF 156889; B, D); nf, navicular facet; pcf, posterolateral calcaneal facet.

The distal articular surfice contains a large navicular in contrast to the larger development of non-articular
facet and a small, but distinct  cuboid facet (not illu- areas seen in advanced equines such as Equus. On the
strated). ectocuneiform the proximal and distal articular surfaces

With regard to the other more distal ankle bones, the contain  respectively, continuous navicular and MT III
mean anteroposterior length (26.5 mm, N = 2) of the facets and lack the separation (or subdivisions) ofthese
navicular is essentially the same as the mean transverse facets seen in advanced equines such as Equus (Hussain
width (26.9 mm, N = 2). These proportions are similar 1975). The proximal surface of the cuboid contains a
to more advanced equines, and contrasts with large calcaneal facet and small astragalar facet (Fig. 15).
Mesohippus, where in the latter genus the anteroposterior There are well developed posterior navicular and
length is greater than the transverse width (Hussain ectocuneiform facets on the internal surface ofthe cuboid.
1975). This increased transverse width in Anchitherium The distal part ofthe cuboid (UF 66944) contains facets
clarencei reflects the emphasis on MI' III relative to either for articulation of the MT III and MT IV; both of these
MT II or IV. The proximal (astragalar) facet of the are relatively smaller in their development in contrast to
navicular in A. clarence; is concave and lacks the non- the condition in advanced equines such as Equus. The
articular area seen in more advanced horses. The distal presence ofwell developed facets for MT III and MT IV
articular surface of the navicular is convex and has a in Anchitherium is advanced relative toMesoh*pus, the
well developed continuous ectocuneiform facet (Fig. 14) latter ofwhich lacks the cuboid-MI' III articulation. As



MacFADDEN: Three-toed browsing horse Anchitherium clarencei from Early Miocene (Hemingfordian) Thomas Farm, Florida 101

A C All-

01 2
1 1 I cm

B D mtillf
./- alill

, 9, r

\ ef

Figure 14 . Navicular (UF 43601 , A, B) and ectocuneiform (UF 60717, C, D) of Anchitherium clarencei from
Thomas Farm, proximal (A, C) and ventral (B, D) views, respectively. af, astragalar facet. ef, ectocuneiform facet;
nf, navicular facet; mtIIIf, met:atarsal III facet.

noted by Hussain ( 1975), on the cuboid ofAnchitherium mean (N = 3 , MCZ 7608 [2], UF 155081 ) observed ratio
there is a well developed tubercle for attachment of the of DSTB/DSAR is 3 1.5/29.2, indicating the more
plantar ligament. primitive morphology. In anterior view and at the distal-

The MT III ofA. clarencei is at the lower end ofthe most part of the MT III shaft there is a distal articular
observed range (mean GRTL=218.7 mm) forthe sample concavity which allows for more rotation ofthe proximal
of New World Anchitherium measured during this study phalanx. The distal sagittal (trochlear) ridge ofthe distal
(Table 1). On the proximal articular surface (Fig. 16) articular surface is well developed posteriorly, is faint
there is a large and continuous ectocuneiform facet that along the distalmost curve, and is absent on the
lacks the non-articular area seen in advanced equines corresponding anterior trochlear surface (Fig. 16). This
such as Equus (Fig. 16). On the posteromedial part of development of the sagittal ridge is characteristic of
the proximal articular surface there is a mesentocuneiforn tridactyl horses. In more advanced monodactyl horses
facet; posterolaterally there is a well developed cuboid such as Equus, this ridge extends for a greater part of its
facet. Just distal to the proximal articular surface on the circumference onto the anterior articular surface; its
caudal part of the MT III shaft there are well developed function is to restrict lateral motion ofthe foot (Hussain
facets for articulation with MT II and MT IV. These 1975).
prominent facets indicate a high level offunctionality of Miscellaneouspodials. Given the lack ofassociation
the lateral metapodials relative to more advanced equids ofskeletal elements (i.e., virtually all bones collected at
(Hussain 1975). In primitive horses, the mean width of Thomas Farm are disassociated), it is unclear whether the
the distal tuberosities (DSTB) is greater than the width remainding footbones listed above in "Referred Specimens"
across the condyles ofthe distal articular surface (DSAR, belong to the fore- or hindlimbs. Nevertheless, there are
Table 1). In advanced, monodactyl horses the reverse is some important characters preserved in these podials.
normally observed (Hussain 1975 ). ForA. clarencei, the A partial lateral metapodial (either II or IV,



102 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 43(3)

pit undifferentiated, UF/FGS V-5273), which preserves the
cf distal one-quarter of this bone (Fig. 17), indicates a

), relatively robust shaft withno evidence ofdistal reduction
A seen in more advanced, particularly monodactyl, horses.

The distal articular surface has a weak sagittal ridge (not
illustrated) for articulation ofthe proximal phalanx.This

af ridge extends only about halfway along this surface.
The proximal medial (III) phalanx ofA. clanncei is

short in contrast to more advanced horses in which this
elementis elongatcd relative to the medial (2nd) phalanx

nf III (Fig. 17). The proximal articular surface of the
proximal central phalanx has a groove that is developed
on the plantar half of this area, but does not extend
dorsally to the extent seen in advanced equines. This
groove articulates with the distal sagittal ridge of the

1

MT III. On the plantar side of the proximal medial
phalanxthere is aprominent proximal V-scar that extends

scar for the attachment of digital ligaments is shorter
about one-third the length ofthe shaft (Fig. 18). This V-

than is seen on more advanced equines (Camp and Smith
1942; Sondaar 1968; Hussain 1975). The mean length
(27.8 mm, N = 2) of the medial central (III) phalanx is

mtillf ec 72 percent the mean length (38.4 mm, N = 3) of the
proximal central (III) phalanx. The meantransverse width
of the medial central phalanx is approximately equal to

c the mean length (29.4 mm, N = 2).
The proximal (Fig. 17) and medial phalanges ofthe

metapodials n and IV ofA. clarencei from Thomas Farm
are characteristically equid as described in Sondaar
(1968) and Hussain (1975). The distal articular surface
ofthe proximal lateral metapodial lacks a sagittal ridge,
indicating increased lateral flexibility of the side toes

mtIVf relative to more advanced equids. As represented by
0 1 2 UF204948, the distal (ungual) phalanx ofthe medial digit

1 I Icm III ofA. clarencei is primitive in several aspects. Relative
to Equus, in life the proximal articular surface (for
articulation with the medial phalanx) would have
indicated a less digitigrade stance, where more of the

Figure 15. Right cuboid (UF 66944) of Anchitherium sole ofthe hoofwould contact the ground during normal
clarencei from Thomas Farm. (A) proximal articular resting stance. The "V-shaped slit" (Fig. 17F) is well

surface, (B) internal (medial) view), (C) distal articular developed in A. clarencei relative to Equus and other

surface. af, astragalar facet; cf, calcaneal facet; ec, advanced, monodactyl equids (Husgnin 1975). Several
ectocuneiform facet; mtIIIf, MT III facet; mtIVf, MT specimens are preserved of the lateral distal (ungual)
IV facet; nf, navicular facet; plt, plantar ligament phalanx (Fig. 17G). This forms an assymetrical, well

tubercle. developed hoof core for the side toe. It has a prominent
extensor process developed on the proximal articular
surface. Hussain (1975) noted that the extensor process
is present in fossil equids such as anchitheres and
Merychippus and indicates muscular activity and
functioning lateral digits.



MacFADDEN: Three-toed browsing horse Anchitherium clarencei from Early Miocene (Hemingfordian) Thomas Farm, Florida 103

A C~-imf

1 ef
cf

D
1

mtllf
mtIVf

E

dac

012
dsrlcm

Figure 16 . Right metatarsal III (MCZ 7608) of Anchitherium clarencei from Thomas Farm, (A) anterior view, (B)
posterior view, (C) proximal articular surface, (D) posterior view of proximal one-quarter, showing facets, (E) distal
articular surface, with anterior aspect above and posterior aspect below showing development of distal saggital ridge.
cf, cuboid facet; dac, distai articular concavity; dsr, distal saggitai ridge; ef, ectocuneiform facet; mf, mesentocuneiform
facet; mtIIf, MT II facet; mtIVf, MT IV facet.



104 BULLETIN ELORIDA MUSEUM NATURAL HISTORY VOL. 43(3)

A B C

.C
71
-

F . G_ID E
3*Vft'56881.~~~

012
1 1 Icm

Figure 17. (A) External view of lateral metapodial (UF/FGS V-5273) ofAnchithenum clanncei from Thomas Farm.
Ventral views ofproximal (B, UF 98400) and medial (D, UF 175395) phalanges III ofAnchitherium clarencei from
Thomas Farm compared to proximal (C) and medial phalanges (E) of extant donkey Equus asinus, UF 156889. (F)
Dorsal view of distal (ungual) phalanx III of A. clanncei, UF 204948. v, V-shaped slit. (G) Dorsal view of lateral
distal phalanx. ep, extensor process.

DISCUSSION Anchitherium Meyer 1844 and Kalobatippus
Until recently a comparison of North American Osborn 1915.-The question of the potential validity

Anchitherium and Kalobatippus has been hampered by of these two genera relates to the variation of their
the lack of relevant material and sufficently large fundamental differentia, some of which cannot be
statistical samples with which to evaluate intraspecific assessed given the available material  whereas others can
versus higher-level variation. Therefore, the sample of be addressed at this time. Two salient characters of
A. clarencei accumulated over more than a half-century generic significance include the reduction in the m3
of sporadic digging at Thomas Farm is important to an hypoconid heel and the relative slenderness/robustness
understanding of the phylogeny and distribution of ofthe metapodials. From the specimens examined during
anchithere horses, which are characteristically rare in this study it seems that there is a morphocline in the
the fossil record. reduction ofthe m3 heel fromMiohippus to Kalobatippus



MacFADDEN: Three-toed browsing horse Anchitherium clarencei from Early Miocene (Hemingfordian) Thomas Fann, Florida 105

A

\\ III/11- 111.fj// 111111

0 1 2
i I cm 11*jit.

Figure 18. Ventral views ofproximal phalanx III showing the development ofthe V-scar of Anchitherium clanncei
(UF 175395) from Thomas Farm (A) compared to that of extant Equus asinus (UF 156889, B).

to Anchitherium to Hypohippus (Fig. 4). As described Anchitherium and this hallmark character serves, along
above the relative development (length) ofthe m3 heel in with the relative reduction ofthe m3 heel, to differentiate
Anchitherium is shorter than in Kalobatippus (Table 1; these two tan.
m3ratio). This, therefore, seems to be a valid character Thomas Farm Anchitherium clarencei and Old
to discriminate these two genera. World dispersal.-The reduction ofthe m3 heel in UF/

The population variation of metapodials can be FGS V-5243 and the relatively robust MT III proportions
assessed from a sample of Anchitherium sp. from the (Fig. 19) justify assignment of the Thomas Farm
early Hemingfordian Bridgeport L. E of Nebraska. anchithere to Anchitherium. Simpson's species A.
Statistical analyses (N = 15) indicate that specimens from clarencei seems valid, although a detailed comparison
this quarry form a tight group, all of which are more with the closely related, slightly smaller A. navasotae
robust than in the type and referred specimens of (Hay 1924; Forsten 1975) and other currently
Kalobatippus (Fig. 19). Furthermore, the Coefficents of undescribed species (e.g., as preserved in the Frick
Variation (CVs) for all measured MT III characters are Collection) is warranted. A. clarencei possesses many
less than 5% (Table 3), which fall within acceptable limits characters that make this species similar to Old World
f6r a uniform sample population ofa fossil morphospecies Anchitherium, including size, reduction of the m3 heel,
(Simpson et al. 1960; MacFadden 1989). Thus, it seems robust metapodials, triangular shape of the hypostyle,
that there is not continuous variation in the relative and presence of an internal cingulum on the upper
robustness of metapodials of Kalobatippus and premolars .



106 
B

U
LLE

TIN
 FLO

R
ID

A M
U

SEU
M

 N
ATU

R
AL H

ISTO
R

Y VO
L. 43(3)

270

/El
260 A. species =

Bridgeport Q.
K. agatensis

G
re

at
es

t P
ro

xi
m

od
is

ta
l L

en
gt

h 
(G

RT
L,
 m

m
)

250 Agate O =/

240 A. large sp.
Harrison Fm.

230
K. praestens
John Day

no I
A. clarencei

K. avus Thomas Farm
210 Harrison Fm.

K species
~~ 1~Stenomylus Q.

190 1 1 1 1 1 1 1
14 16 18 20 22 24 26 28 30 32

Midshaft width (MDSH, mm)

Figure 19. Bivariate plot of midshaft width of MTIII versus greatest proximodistal length for North American
species of Kalobatippus and Anchitherium measured during this stu*.



MacFADDEN: Three-toed browsing horse Anchitherium clarence, from Early Miocene (Hemingfordian) Thomas Farm, Florida 107

Table 3. Univariate statistics, including variation parameters, from a population ofAnchitherium sp. from the Bridgeport
Quarry, Hemingfordian of western Nebraska (University of Nebraska State Museum locality MO 113 and 114). For
character abbreviations see text and Figure 3.

Character N Mean CV (%) Range (minimum to maximum)

GRTL 15 247.6 6.5 2.62 235.5-259.0

PRXW 12 32.8 1.0 3.05 31.2-34.1

MDSH 15 24.1 1.2 4.98 22.1-26.8

DSTB 15 34.2 1.4 4.09 31.1-36.9

DSAR 14 30.5 1.1 3.61 29.2-33.4

The postcranial elements represented in Thomas locality in north-central Florida. The accumulation of
Farm A. clarencei mostly confirm previous ideas about these fossils during this time now allows a better
the functional morphology and stage of evolution of understanding of the morphology and systematics of
Anchitherium in general (e .g ., Camp and Smith 1942 ; Anchitherium clarencei Simpson, 1932, and such other
Sondaar 1968 ; Hussain 1975) . In particular, the shape primitive brachyodont horses as Kalobatippus . A
and relative development of articular facets on the reappraisal of the validity and distribution of
metapodial, wrist, ankle, and phalangeal bones indicate Kalobatippus and Anchitherium indicates that both
a functionally tridactyl horse in which the fore- and hind- genera existed in North America. A. clarencei was
feet retained some ofthe flexibility seen in more primitive widespread in North America during a very narrow time
horses. A. clarencei lacked the passive stay apparatus interval between about 18 and 17 Myr ago; it also
developed in the forelimb of advanced horses such as persisted locally in the early Barstovian of Florida. A.
Dinohippus and Equus (Hermanson and MacFadden clarencei is morphologically very similar to Old World
1992). Anchitherium and its occurrence at 17-18 Myr ago, which

So far as the available evidence indicates, corresponds to Planktonic Foraminiferal zones N5 to N7,
Anchitherium dispersed into the Old World, but is consistent with this horse being a part of the middle
Kalobatippus did not. Species like A. clarencei Miocene intercontinental Holarctic dispersal across the
demonstrate the morphological complex of characters Bering land bridge. So far as is known, Kalobat*pus
seen in Old World Anchitherium, particularly size, did not disperse into the Old World. The morphology of
reduced m3 heel , triangular hypostyle , and internal thefootofA. clarencei indicates a relatively high degree
cingulum development. In addition to morphological of flexibility and functional tridactyly.
similarities, the occurrence of A. clarencei during the Althougb many studies over the past several decades
early Hemingfordian makes it a reasonable temporal have concentrated on unravelling the complex
candidate for dispersal during a major time of Holarctic interrelationships offossil horses, fertile ground remains
faunal interchange atabout 18 Ma. (Tedford etal. 1987; for a detailed phylogenetic study of the anchitheres,
Woodburne and Swisher 1995; Sanchez etal. 1998) and currently a horizontal assemblage of species traditionally
thereafter when they become part ofthe middle Miocene referred to the North American genera Miohippus,
"Anchitherium faunas" ofthe Old World . Anchitherium, Kalobatippus, Hypohippus, and Mega-

hippus. Once this is accomplished, then comparative
SUMMARY AND CONCLUSIONS evolutionary and ecological studies can be undertaken

For over a half-century fossil horses have been to better understand the paleobiology of this interesting,
collected from the rich Hemingfordian Thomas Farm yet relatively poorly known, group of fossil horses.



108 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 43(2)

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, 45
r -r 1



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