Ursus minimus Baryshnikov Lavrov 2013

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© RUSSIAN JOURNAL OF THERIOLOGY, 2013
Russian J. Theriol. 12(2): 107118
The earliest member of the genus Ursus is regarded
to be the fossil bear U. minimus Devèze de Chabriol et
Bouillet, 1827 (=U. arvernensis Croizet et Jobert, 1828),
which presumably was the ancestral taxon for black
bears, cave bears, and brown bears of Eurasia and
North America (Baryshnikov, 2007). The greatest sim-
ilarity of U. minimus to the Asian black bear (U. thibet-
anus) is expressed in their dental morphology. Hence,
the findings of the teeth of Pliocene ursids in Europe
are often determinated as U. ex gr. minimus-thibetanus
(Wagner, 2010).
U. minimus is represented by cranial fragments,
lower jaws, isolated teeth and some bones of postcrani-
al skeleton (Croizet & Jobert, 1828; Depéret, 1890;
Maier von Mayerfels, 1929; Roshchin, 1956; Ryziewicz,
1969, Berzi, 1966; Jánossy, 1978; etc.). However, its
taxonomic position remains questionable. Some re-
searchers divide U. minimus for several taxa: U. boeck-
hi Schlosser, 1899 (Early Pliocene, Europe), U. mini-
mus s.str. (Late Pliocene, Europe), U. yinanensis Li,
1993 (Late Pliocene, China) and U. abstrusus Bjork,
1970 (Early Pliocene, North America) (Li, 1993; Ted-
ford & Harington, 2003; Wagner, 2010). The others
Introduction
All recent bears of the Old World (except of bam-
boo bear, Ailuropoda melanoleuca (David, 1869) be-
long to the tribe Ursini Fischer, 1814 and derive (ac-
cording to the data of mitochondrial phylogeny) from
bears of the New World (tribe Arctotheriini F. Ameghi-
no, 1903) at the beginning of the Late Miocene (Torto-
nian), near 12.86 Ma (Krause et al., 2008). The ances-
tor of ursine bears is regarded to be a member of the
genus Ursavus Schlosser, 1899, presumably U. pri-
maevus (Gaillard, 1899) (Baryshnikov, 2007).
Ursine bears radiation occurred at the time corre-
sponding to the time period near the Miocene-Pliocene
boundary (5.39 Ma by molecular data). The basal posi-
tion by molecular phylogeny (see Krause et al., 2008) is
occupied by the sloth bear, Melursus ursinus (Shaw,
1791). The appearance of the genus Ursus L., 1758, is
referred to the beginning of the Pliocene (5.05 Ma).
The time of divergence of the two species of black
bears (Ursus thibetanus G. Cuvier, 1823 and U. amer-
icanus Pallas, 1780) was determinate as 4.08 Ma.
Pliocene bear Ursus minimus Devèze de Chabriol et Bouillet, 1827
(Carnivora, Ursidae) in Russia and Kazakhstan
Gennady F. Baryshnikov & Alexander V. Lavrov
ABSTRACT. Mandibular fragments of the small Pliocene bear from Kosyakino in Northern Caucasus,
Russia (MN15) and from Moiseevka in Irtysh River basin, Kazakhstan (MN14) revealed morphological
similarity with the specimens of Ursus minimus. During the evolution of this species, the enlargement of
molars and equalization of the m1 and m2 in length took place. Our study ascertained the presence of
geographical variability of U. minimus in Eurasia in the Early Pliocene (U. m. boeckhi in Europe and U. m.
ssp. in Kazakhstan) as well as in the Late Pliocene (U. m. minimus in Europe and U. m. yinanensis in China).
KEY WORDS: Ursus minimus, Ursidae, Pliocene, Caucasus, Kazakhstan.
Gennady F. Baryshnikov [G_Baryshnikov@mail.ru], Zoological Institute, Russian Academy of Sciences, Univer-
sitetskaya nab. 1, Saint Petersburg 199034, Russia; Alexander V. Lavrov [lavrov@paleo.ru], A. A. Borissiak
Paleontological Institute, Russian Academy of Sciences, Profsoyuznaya ul. 123, Moscow 117647, Russia.
Ïëèîöåíîâûé ìåäâåäü Ursus minimus Devèze de Chabriol et
Bouillet, 1827 (Carnivora, Ursidae) â Ðîññèè è Êàçàõñòàíå
Ã.Ô. Áàðûøíèêîâ, À.Â. Ëàâðîâ
ÐÅÇÞÌÅ. Ôðàãìåíòû íèæíå÷åëþñòíûõ êîñòåé ìàëåíüêîãî ïëèîöåíîâîãî ìåäâåäÿ èç ìåñòîíàõîæ-
äåíèé Êîñÿêèíî íà Ñåâåðíîì Êàâêàçå, Ðîññèÿ (MN15), è Ìîèñååâêà â áàññåéíå ðåêè Èðòûø,
Êàçàõñòàí (MN14), îáíàðóæèëè ìîðôîëîãè÷åñêîå ñõîäñòâî ñ îáðàçöàìè Ursus minimus.  ïðîöåññå
ýâîëþöèè âèäà ïðîèñõîäèëî óâåëè÷åíèå ðàçìåðîâ êîðåííûõ çóáîâ è èìåëî ìåñòî âûðàâíèâàíèå
äëèíû m1 è m2. Íàøå èññëåäîâàíèå ïîäòâåðäèëî ñóùåñòâîâàíèå ó U. minimus â Åâðàçèè ãåîãðàôè-
÷åñêîé èçìåí÷èâîñòè êàê â ðàííåì ïëèîöåíå (U. m. boeckhi in Europe and U. m. ssp. in Kazakhstan),
òàê è â ïîçäíåì ïëèîöåíå (U. m. minimus in Europe and U. m. yinanensis in China).
ÊËÞ×ÅÂÛÅ ÑËÎÂÀ: Ursus minimus, Ursidae, ïëèîöåí, Êàâêàç, Êàçàõñòàí.

108 G.F. Baryshnikov & A.V. Lavrov
consider these taxa to be subspecies of the single poly-
typical species of U. minimus, which formed the Pan-
Holarctic distribution (Baryshnikov, 2007). Some pale-
ontologists consider that all bear fossils from Europe of
this age belong to a single species  U. minimus
(Morlo & Kundrát, 2001). Moreover, the idea has been
put forward on separating of black bears in two genera:
Protarctos Kretzoi, 1945 (P. boeckhi, MN14; P. rus-
cinensis Depéret, 1890, MN15; P. yinanensis, MN16
17), and Euarctos Gray, 1864 (E. pyrenaicus Depéret,
1892, MN15; E. minimus, MN1617; and recent spe-
cies: E. thibetanus and American baribal E. america-
nus), was suggested by Qui et al. (2009). Thus the
species U. thibetanus and U. americanus are excluded
from the genus Ursus. However, this opinion is based
mainly on the morphology of one tooth m1 only. This
point of view is disputable by the reasons of the signif-
icant variability of dental characters in bears as well as
molecular studies supporting the monophyly of the ge-
nus Ursus (Pagés et al., 2008).
European findings of U. minimus in the Early Rus-
cinian (MN14) are known from Alcoy in Spain, Mont-
pellier in France (MN14a), Kuchurganian beds (Tru-
domirovka) in Ukraine, Baraolt-Cãpeni in Romania
(=Barót-Köpecz in Hungary), and Dorkovo in Bulgaria
(Schlosser, 1899; Maier von Mayerfels, 1929; Korot-
kevich, 1967; Dubrovo & Kapelist, 1979; Spassov,
2003; Montoya et al., 2006; Wagner, 2006). In the late
Ruscinian and early Villanyian localities, the species
was recorded in Perpignan, France (MN15a), Layna,
Spain and Wê¿e 1, Poland (MN 15b), Wölfersheim,
Germany (MN15b), Odessa Catacombs, Ukraine (MN
15/16), Gaville, Triversa, Arondelli, Ponzano, Italy
(MN16), Les Etouaires, France (MN16b), Vèeláre 2,
Slovakia (probably MN16), and Osztramos 7, Hungary
(MN16b) (Roshchin, 1956; Berzi, 1966; Ryziewicz,
1969; Soria & Morales, 1976; Jánossy, 1978; Mazza &
Rustioni, 1994; Alberdi et al., 1997; Morlo & Kundrát,
2001; Sabol et al., 2008; Wagner, 2010; Wagner et al.,
2012). Bears from aforementioned localities had been
referred to different taxa, but later were assigned to U.
minimus (synonymy see in Baryshnikov, 2007).
In Asia, U. minimus was discovered in Kvabebi,
Georgia (MN16, Vekua, 1972), Kosyakino and Udun-
ga (MN15) in Russia (Vereshchagin, 1959; Sotnikova
& Kalmykov, 1991; Baryshnikov, 2007; Sotnikova,
2008), as well as in Yushe (as Ursus sp.), Liang-Chia-
Ho [as U. cf. boeckhi; assigned to Helarctos sinoma-
layanus by Thenius (1947)] and Yinan (as U. yinanen-
sis, MN16/17) in China (Zdansky, 1927; Teilhard de
Chardin, 1940; Qiu et al., 2009). In North America,
there are several findings (as U. abstrusus) in the Early
Blancanian sites (Hagerman, White Bluffs, Buckeye
Creek) and Late Blancanian sites (Cita Canyon) in the
USA (Kurtén & Andersen, 1980; Kelly, 1994) and in
Canadian Arctic (Elsmere Island; Tedford & Haring-
ton, 2003).
Though the remains of Ursus minimus are known
from numerous localities, the findings of this species
are rather rare. The evolutionary changes of teeth and
Figure 1. The geographic positions of the localities of Ursus minimus considered in the paper.
1  Kosyakino, 2  Moiseevka.

109
Pliocene Ursus minimus in Russia and Kazakhstan
skull characters of this species, as well as its variability,
remain unclear. Therefore, the prior attention was giv-
en to the complete description of the material from the
territories of Russia and Kazakhstan. This material
makes possible estimating of morphological changes
throughout all specific range of U. minimus from West
European to Chinese localities.
In this publication we describe the morphological
features of the lower jaws from Northern Caucasus
(Kosyakino) and from the northern part of Kazakhstan
(Moiseevka) for the first time (Fig. 1). Examined ma-
terial is stored in Zoological Institute, Russian Acade-
my of Sciences in St. Petersburg (ZIN) and in A.A.
Borissiak Paleontological Institute, Russian Academy
of Sciences in Moscow (PIN). For comparative analy-
sis, we used the collections of several European depos-
itories (see Institutional abbreviations).
In the definition of the mammal ages and their corre-
lation with the chronostratigraphical scale as well as the
MN-zones we follow Mein (1990), Fejfar & Heinrich
(1990), Fejfar et al. (1998), and Wagner et al. (2012).
Institutional abbreviations. CBUL  Claude Ber-
nard University Lyon 1, Villerbann, France; IGF 
Museo di Storia Naturale, Sezione Geologia e Paleon-
tologia, Università di Firenze, Italy; ISEA  Institute
of Systematics and Evolution of Animals, Krakow,
Poland; SNMB  Slovak National Museum, Bratisla-
va, Slovakia; NHMN  Muséum National dHistoire
Naturelle, Paris, France; PIN  A. A. Borissiak Pale-
ontological Institute, Russian Academy of Sciences,
Moscow, Russia; ZIN  Zoological Institute of the
Russian Academy of Sciences, Saint Petersburg, Russia.
Localities and material
Kosyakino. This locality (sand quarry) is situated
near Stavropol city in Northern Caucasus, Russia
(45°03¢N, 41°57¢E). The mammalian fossils were lo-
cated in the sandy alluvial deposits and were redeposit-
ed by the ancient river (Vereshchagin, 1959).
Originally the list of mammalian taxa from this
locality included: Ursus cf. arvernensis Croiz. et Job.,
Dinocyon cf. thenardi Jourd., Felis cf. issiodorensis
Croiz. et Job., Ochotona cf. antiqua Pidopl., Lepus sp.,
Amblicastor caucasicus Argirop., Steneofiber sp., Anan-
cus arvernensis Aymard, Dinotherium sp., Hipparion
gracile Kaup, Tapirus cf. arvernensis Croiz. et Job.,
Figure 2. The fragment of the right mandibular ramus of Ursus minimus from Kosyakino, Northern Caucasus (ZIN 34996);
labial (A), lingual (B) and occlusal (C, D) views.

110 G.F. Baryshnikov & A.V. Lavrov
Dicerorhinus orientalis Schlosser, Aceratotherium cf.
incisivum Kaup, Propotamochoerus provincialis Ger-
vais, Procapreolus sp., Pliocervus sp., Pseudalces sp.,
Gazella sp., etc. (Argiropulo, 1939, 1940; Beliaeva,
1940, 1944; Vereshchagin, 1959).
Later some of these taxa were redefined. The beaver
Amblicastor caucasicus was determinated as porcupine
Hystrix caucasicus (Lopatin et al., 2003); hemicyonid
Dinocyon cf. thenardi as ursid Agriotherium sivalense
minutum Gerv. (Baryshnikov, 2007). The list of the
lagomorph species was also modified: Prolagus cauca-
sicus Averianov et Tesakov, Ochotona cf. antiqua,
Hypolagus cf. igromovi Gureev (Averianov & Tesa-
kov, 1998).
The geological age of Kosyakino is determinated as
Early Ruscinian (MN14) based on lagomorphs (Averi-
anov & Tesakov, 1998) or as Late Ruscinian (MN15)
according to carnivores data (Vislobokova et al., 2001).
Ursid findings from Kosyakino were represented by
two right mandible fragments. The specimen ZIN 34996
(Fig. 2) includes the lower canine, alveoli p1p3 and
also cheek teeth p4 and m1. The color of bone is light
gray. Tooth enamel is light brown, with indistinct dark
spots (collected by N.K. Vereshchagin in September
13, 1953). The specimen PIN No.225/253 (Fig. 3)
includes the fragment of the lower canine, alveoli p1
p3 and molars m1-m2. The bone is dense; its color is
beige turning to light brown. Tooth enamel is colored
as that of the specimen ZIN 34996. The bone mineral-
ization is high. Vereshchagin (1959: Fig. 24, 1, 3)
identified the lower jaw fragments from Kosyakino as
Ursus cf. arvernensis but not described it. This paper
includes illustrations of both lower jaw fragments of
ursids from Kosyakino. Vereshchagin (1959) reported
that 12 ursid bones totally were collected in the locality.
Moiseevka. The locality is situated at the right bank
of the Irtysh River near Moiseevka village in Zhelezin-
sky District of Pavlodar Region, Kazakhstan (53°27¢N,
75°28¢E). The age of the finding is not precise, but
Pliocene age is mentioned in the museum label.
The member of green clay is located at the left bank
of the Irtysh River; these clays were dated as Oligocene 
Middle Miocene. The same type of deposits is present
at the right bank of the Irtysh River. This member is
overlain by Late Miocene and Pliocene deposits (Niki-
forova, 1953). Near from the village Moiseevka the
member sandy (psammitic) and marlaceous clays was
established as Moissevskaya svita, in which were found
fossils of Equus stenonis Cocchi fossils (Kostenko,
1963). Zinova (1982) included Moissevskaya svita as a
member within the compound of Podpusk-Lebiazchin-
skaya svita characterized by presence of Archidiskodon
gromovi Garutt et Alex., Equus stenonis Cocchi, Elas-
motherium sp., Gazella cf. sinensis Teih. et Piv.,
Vulpes odessanus Odinz. (=Eocyon odessanus, see
Sotnikova & Rock, 2010). E. Vangengeim (1977) con-
sidered that Podpusk-Lebiazchinskaya svita is analo-
gous to Khaprovian age (Middle Villafranchian) of
Eastern Europe. Vislobokova (1996) noted a presence
of faunal horizons dated earlier than Middle Villafran-
chian in the Moisevskaya svita.
Deposits of Novostanychnaya svita (stratum) in the
neighborhood of the Moiseevka village are of Middle
Pliocene age (Zinova, 1982: 44). In the deposits of this
unit the bones of small mammals Desmanidae gen.?,
Steneofiber, Prosiphneus, and Baranomys had been
collected. According to the opinion of Zazhigin (1980)
the presence of Baranomys and degree of evolutionary
development of beaver Steneofiber teeth makes possi-
ble attribution of Novostanychnaya svita to the horizon
directly below the Akchaghylian beds. Its very likely
that described lower jaw originates from these deposits.
The deposits of this svita have been later attributed by
V. Zazhigin to the Late Miocene (MN13; Zykin et al.,
2007). We determine the age of the ursid lower jaw
from Moiseevka approximately as Early Pliocene (Ear-
ly Ruscinian, MN14). This suggestion confirmed by the
ursids morphological features described below.
Describing material from Kazakhstan presented by
right ramus of the lower jaw with m1m2 (PIN No.5332/
1). It was found at the right bank of Irtysh River (out-
crop number 130, specimen 207) in 2.5 km upstream
from the Moiseevka village, Omsk Region (now Pavlo-
dar region, Kazakhstan), collected by K. Nikiforova,
Institute of Geological Sciences of Academy of Scienc-
es of USSR, Moscow, September 7, 1948. The bone
color is dark gray. Teeth are well preserved, the enamel
is brown colored. The specimen was identified and
labeled as Ursus arvernensis. This specimen was nei-
ther described nor figured earlier.
Systematic Paleontology
Order Carnivora Bowdich, 1821
Family Ursidae Fischer, 1814
Genus Ursus Linnaeus, 1758
Ursus minimus Devèze de Chabriol et Bouillet, 1827
Description. Kosyakino (ZIN 34996, PIN No.225/
253; Figs. 2, 3). The lower margin of the mandible is
straight. The ramus is high; its height is decreasing
forward. The mandibular symphysis is short, reaches
the level of the premolar p3; a chin prominent at the
ventro-caudal symphyseal edge is relatively small, but
its well expressed. The masseteric fossa is rather shal-
low and extends anteriorly to the level of the posterior
margin of m3. Judging by the preserved part of the
coronoid process, its anterior margin should be gradu-
ally upraised over the tooth row. There are two mental
foramina: the anterior one is located at the level be-
tween p2/p3 and posterior one is located directly below
the contact between p4 and m1.
The axis of the tooth row is slightly curved in dorsal
projection. There is an angle between the axes of pre-
molar and molar rows. The masticatory surface of m3 is
inclined anteriorly.
The shape of the canine is typical for bears. There
are two carnassial ridges on the enamel surface (anteri-

111
Pliocene Ursus minimus in Russia and Kazakhstan
Figure 3. The right mandibular ramus of Ursus minimus from Kosyakino, Northern Caucasus (PIN No.225/253); labial (A),
lingual (B) and occlusal (C, D) views.
or and posterior one). These ridges are slightly notched
and run from the basis of the crown toward the canine
apex. Also, a weakly developed ridge runs along the
middle line of the lingual side of the crown. The tooth is
somewhat turned along the longitudinal axis, so that the
longitudinal axis is directed lingual from the row of
cheek teeth.
The row of anterior premolars p1p3 is crowded
towards the canine. The postcanine diastema is absent.
The teeth p1 and p2 were single-rooted. The premolar
p3 in ZIN 34996 is single-rooted as well. In the speci-
men PIN No.225/253 p3 is completely preserved, its a
small, single-cusped, and double-rooted tooth. In the
recent species of the genus Ursus, the premolar p3 is
single-rooted and frequently absent (in U. arctos L., U.
maritimus Phipps).
The premolar p4 has two separated roots. There are
two longitudinal enamel crests run nearly from basis of

112 G.F. Baryshnikov & A.V. Lavrov
the crown to the apex of the main cusp. The anterior
keel runs from a small cuspid near the crown margin.
The posterior keel passes into elongated horizontal
ridge. There is a slender buccal cingulid, which is better
developed in the posterior portion of the tooth crown.
The lingual cingulid is well expressed. It is looks like to
a ridge in the posterior portion of the crown. It is
upraised directly behind the base of the main cusp and
forms separated cuspid (probably metaconid).
The lower carnassial tooth m1 is comparatively
small in contrast to other bears. The habitus of m1 is
rather compact: its length is approximately twice the
tooth width. The paraconid is short, shaped as a sharp
tubercle; its anterior margin is parallel to the dorso-
ventral axis. The paraconid is approximately equal to
metaconid in height. The protoconid is robust, high and
has a trenchant anterior margin. The carnassials notch
between paraconid and protoconid is rather shallow.
The metaconid is massive, well separated from the
protoconid. It is shifted posteriorly far from the caudal
margin of the protoconid. In the specimen PIN No.225/
253, the metaconid has a single apex (Fig. 3D), whereas
the specimen ZIN 34996 has an accessorial cusp
(premetaconid) in front of the metaconid (Fig. 2D),
similar to recent black bears and brown bears. The
talonid portion is comparatively short (the length being
nearly equal to the width) and doesnt have the inner
basin. The talonid is slightly wider than the trigonid,
and there is a slightly expressed constriction between
them. The greater part of the talonid is formed by the
hypoconid which looks like a high three-edged cusp.
The hypoconid possesses no separated inner structure
in contrast to cave bears and brown bears. The ento-
conid is divided from the hypoconid. The entoconid has
a single apex and is significantly smaller and lower than
the hypoconid. There is a small entoconulid (ZIN 34996)
in front of the entoconid. It is necessary to note that the
entoconulid is absent on the specimen PIN No.225/
253. The hypoconulid is absent in ZIN 34996. The
posterior part of the crown has a distinct buccal cin-
gulid. The lingual cingulid is absent.
The molar of m2 is slightly smaller in length than
m1. The masticatory surface is subrectangular, without
a distinct constriction. The trigonid and talonid are
nearly equal in width. The anterior margin of the crown
has an arched ridge. The paraconid is not developed.
The protoconid has a single apex and it is rather low.
The metaconid do not have an additional tubercles and
it is noticeably higher than the protoconid. The inner
ridges, running from the protoconid and metaconid
merge together. These ridges divide anterior (the trigo-
nid) and posterior (the talonid) parts of the interior
region of the crown. The anterior part of the crown is
cup-shaped and comparatively small. The posterior part
is more extensive, spreading onto the talonid and dis-
playing enamel folds. The hypoconid is single-cusped
and it tends to form an inner lobe. The entoconid is
ridge-shaped and exceeds hypoconid in height, being
composed of two tubercles divided by a small cuspid.
The distal ridge runs along the posterior margin of the
crown, linking the hypoconid and entoconid; there are
no clear traces of the hypoconulid. The buccal and
lingual cingulids are absent.
The molar m3 is comparatively small and oviform.
A slight separation of the talonid from the trigonid is
traced on the buccal side of the tooth (this separation is
especially well developed in the cave bears). The outer
margin of the crown is upraised like a ridge with slight-
ly expressed protoconid and hypoconid. The lingual
surface of the tooth is somewhat wrinkled.
Moiseevka. The lower margin of the mandible frag-
ment (PIN No.5332/1, Fig. 4) is nearly straight with a
slight concavity below m1; as a result, the height of the
mandibular ramus decreases from the diaphysis to-
wards the level of m1, increasing again at the level of
m2. The symphysal part is large in regard to the mandi-
ble size; it extends backwards up to the level of p2. The
chin (the ventral prominent) is absent. There are two
approximated mental foramina distanced from each
other at 6.3 mm. The posterior opening is located below
the alveolus of p3.
The postcanine diastema is absent. The canine is
broken; its remaining part implies its size was some-
what smaller than that in ZIN 34996 (Kosyakino). The
area between the canine and the molar m1 is occupied
by three alveoli from anterior premolars p1p3, which
were single-rooted, as well as by two alveoli from the
premolar p4.
The lower carnassial tooth is similar by proportions
and shape to the specimen from ZIN 34996 (Kosyaki-
no), being, however, somewhat smaller. The metaconid
is single- cusped, less robust than that in the specimen
from Kosyakino. The hypoconid is large; there is no
accessorial tubercle between it and the protoconid. The
entoconid is shaped like a ridge formed by two closely
spaced cuspids (the first one being higher). The addi-
tional, tiny cuspid (entoconulid) is located in front of
the entoconid, and closes the inner area of talonid from
the lingual side.
The proportions and shape of the molar m2 are
similar to those in PIN No.225/253 from Kosyakino,
but, in contrast to the latter, the tooth is markedly
shorter than m1. The metaconid is robust and single-
cusped. The hypoconid is pronouncedly higher as com-
pared to the entoconid (unlike in PIN No.225/253). The
entoconid is ridge-like, and only two poorly expressed
and widely spaced cuspids are present. The buccal
cingulid is well developed.
Comparison. The comparison of a tooth sizes of U.
minimus from various geological ages (horizons) shows
that tooth sizes increased during the species evolution.
The latest members of the species possess the largest
Figure 4. The fragment of right mandibular ramus of Ursus minimus (PIN No.5332/1) from Moiseevka, Kazakhstan; labial
(A), lingual (B) and occlusal (C, D) views.

113
Pliocene Ursus minimus in Russia and Kazakhstan

114 G.F. Baryshnikov & A.V. Lavrov
U. m. boeckhi U. m. minimus
Baraolt-Cãpeni,
Romania
(=Baróth-Köpec,
Hungary)
Moiseevka,
Kazakhstan
Kosyakino,
Russia
Perpignan,
France
France
(locality
unknown)
Gaville,
Italy
Measurements,
mm
CBUL 3302, cast PIN 5332-1 PIN
225-253
ZIN
34996
CBUL
41.326
NHMN, coll.
Bravard 12q,
cast
IGF
11568,
sin
Length c1m3 ca109 125.3 125.1 136.0
Length c1m2 ca83.9 ca94
Length alvp4m3 66.3 66.1 76.1 76.5
Length alvp4m2 49.2 52.9
Length m1m3 53.2 ca56 54.7 63.1 64.5
Length m1m2 38.2 ca42
Height behind m1 29.9 37.3 36.7 49.5
Height behind p4 39.5 42.6 42.4 49.0
Height behind p2 33.6 35.7 32.8
Teeth
c1 L 14.5 ca17.1 18.7 26.3 23.5 25.0
c1 W 12.6 ca10.0 11.5 13.8 13.8 14.5
p3 L 7.6 7.0
p3 W 4.2 4.5
p4 L 11.9 12.1 13.3 11.4
p4 W 6.1 6.9 7.7 6.9
m1 L 20.9 20.4 ca22.1 21.0 20.4 23.6 25.1
m1 W 9.4 9.4 9.3 9.7 9.1 12.5 11.5
m2 L 17.9 17.9 20.0 20.0 22.5 22.7
m2 W 10.6 11.3 11.2 11.8 15.5 13.8
m3 L 14.5 14.3 15.1 16.3
m3 W 11.6 11.1 11.6 13.5
Table 1. Sizes of the mandibles of Ursus minimus.
cheek teeth (Tabs. 13). The increasing of m2 is nota-
bly expressed: in the specimens from the Early Ruscin-
ian of Europe (Baraolt-Cãpeni, Moiseevka, MN14) the
length of m2 is significantly smaller than that of m1.
However m1 and m2 from the Late Ruscinian speci-
mens (Perpignan, Kosyakino, MN15) are approximate-
ly equal in length. The lower jaw from the Late Villány-
ian (Gaville, MN16) has m1 which is significantly
longer than m2. Moreover, tooth sizes are notably larg-
er than those in the bears from the Early Ruscinian.
Length ratio of m1/m2 of U. minimus yinanensis from
China (Dongxiang, Yinan) are similar to those from the
Early Ruscinian, although the geological age of the
Chinese taxon is more late (it is equal to MN1617; Qiu
et al., 2009). In recent U. thibetanus m1 and m2 are
approximately equal in length. It may be hypothesized
that Asian black bear diverged from the Late Ruscinian
ursids. This proposal was confirmed by the results of
the molecular studies (Talbot & Shields, 1996) and
paleontological data (Baryshnikov & Zakharov, 2013).
All examined specimens have similar proportions
of m1. Height of the paraconid and metaconid is ap-
proximately equal (in the ancestral Miocene Ursavus
primaevus the metaconid is higher than paraconid).
The dimensions of these cusps changed during the
evolution, therefore in the recent Ursus thibetanus the
paraconid is pronouncedly higher than metaconid. The
metaconid, in general, is single-cusped (Baraolt-Cãpe-
ni, Perpignan, Vèeláre). However, many specimens from
Odessa Catacombs and Gaville have premetaconid
(Roshchin, 1956; Berzi, 1966; Ryziewicz, 1969; Vekua,
1972). Even in the same series of specimens this feature
may be rather variable (Kosyakino, Wê¿e 1). Recent
Asian black bear (U. thibetanus) has smaller double-
cusped metaconid connected to protoconid (in some
cases, it can be formed only by a single cusp of the
metaconid).
Evolutionary changes of m1 morphology also in-
clude the increasing of the talonid size, which is en-
larged transversally in the latest representatives of the
species (Tab. 1). In Ursus minimus the talonid and
trigonid are separated by the large transversal groove
facing the lingual side of the crown. The same peculiar-
ities are typical for recent U. thibetanus. This groove
may be of exposed type (ZIN 34996, Kosyakino) or
closed type, in the latter the groove is overlapped by
enamel cuspid close to the tooth border (the specimen
from Moiseevka). The hypoconid of all described spec-
imens is large, its inner lobe is not separated. The
entoconid morphology in described specimens is vari-
able. The entoconid of the most specimens (Baraolt-
Cãpeni, Wê¿e 1, Perpignan, Vèeláre, Odessa Cata-

115
Pliocene Ursus minimus in Russia and Kazakhstan
Table 2. Measurements (mm) of lower molar m1 of Ursus minimus.
Table 3. Measurements (mm) of lower molar m2 of Ursus minimus.
combs, Gaville, and PIN No.225/253, Kosyakino) is
single-cusped and displaced to the caudal side of the
crown. Sometimes there is an accessory cuspid, located
anteriorly from the entoconid (ZIN 34996, Kosyakino).
The entoconid may be ridge-shaped or double-cusped
(Moiseevka specimen). It is necessary to note that the
entoconid of Ursavus primaevus is double-cusped (Bary-
shnikov, 2007: Fig. 59). In recent Ursus thibetanus, as
a rule, the entoconid is singe-cusped.
The structure of the metaconid of m2 is rather dif-
ferent in U. minimus. The metaconid is single-cusped
and nearly equal in height to protoconid (in the speci-
men from Moiseevka locality). Frequently the meta-
conid is considerably higher than protoconid (Baraolt-
Cãpeni, Kosyakino, Perpignan, Odessa Catacombs).
Sometimes there are accessory cuspids, located anteri-
orly and posteriorly from the main cusp of metaconid
(Wê¿e 1, Odessa Catacombs, Kvabebi). The entoconid
is regularly double-cusped and shifted backwards (in
CBUL 3302 from Baraolt-Cãpeni it is single-cusped).
It looks like weakly serrated ridge with more expressed
posterior cuspid (Moiseevka, Perpignan). The ento-
Localities Museum number Greatest
length
Buccal
length of
trigonid
Width
of trigonid
Width
of
talonid
Width of
constric-
tion
U. minimus boeckhi
Baraolt-C²peni, Romania
(MN14)
CBUL 3302, cast 20.9 ca14.4 9.0 9.4 8.7
Moiseevka, Kazakhstan
(early MN15)
PIN 5332-1 20.4 13.2 7.9 9.4 8.1
U. minimus minimus
PIN 225-253 ca22.1 - 7.6 9.3 7.8 Kosyakino, Russia
(MN15) ZIN 34996 21.0 14.1 8.0 9.7 8.0
Perpignan, France
(MN15)
CBUL 41.326 20.4 13.0 8.0 9.1 7.7
ISEA MF/833/67/5 21.0 13.0 7.5 8.8 7.6
ISEA MF/833/67/9 22.8 14.3 8.5 10.9 9.4
ISEA MF/833/67/13 21.2 12.9 7.8 9.1 7.5
ISEA MF/833/67/15 19.2 12.3 7.7 8.5 6.8
WÄüe 1, Poland (MN15)
ISEA MF/833/67/17 19.4 13.1 8.1 9.0 8.3
V¹eláre, Slovakia (MN16) SNMB Z26702 21.4 14.5 8.5 9.3 8.3
France (locality unknown) NHMN, coll. Bravard
12q, cast
23.6 14.4 9.8 12.5 10.2
IGF 11568, sin 25.1 15.2 10.4 11.5 9.2 Gaville, Italy (MN16)
IGF 11568, dex 24.8 16.6 9.7 10.3 8.9
Localities Museum number Greatest
length
Buccal
length of
trigonid
Lingual
length of
trigonid
Width
of
trigonid
Width
of
talonid
U. minimus boeckhi
Baraolt-C²peni, Romania
(MN14)
CBUL 3302, cast 17.9 12.0 - 10.6 10.5
Moiseevka, Kazakhstan
(MN14)
PIN 5332-1 17.9 11.2 9.7 11.3 10.5
U. minimus minimus
Kosyakino, Russia (MN15) PIN 225-253 20.0 12.6 10.0 11.0 11.2
ISEA MF/833/67/6 20.4 12.4 10.4 11.0 11.5
ISEA MF/833/67/7 21.2 12.3 11.5 12.3 11.8
ISEA MF/833/67/8 20.6 13.1 11.8 11.2 11.3
WÄüe 1, Poland (MN15)
ISEA MF/833/67/21 20.5 11.9 11.1 10.9 11.6
Perpignan, France (MN15) CBUL 41.326 20.7 11.6 10.5 11.6 11.8
France (locality unknown) NHMN, coll.
Bravard 12q, cast
22.5 14.8 12.5 15.5 15.0
IGF 11568, sin 22.7 13.2 12.5 12.8 13.8 Gaville, Italy (MN16)
IGF 11568, dex 22.4 13.1 12.8 11.8 12.7

116 G.F. Baryshnikov & A.V. Lavrov
conid of m2 is double-cusped in recent Ursus thibeta-
nus, similar to the aforementioned specimen of U. min-
imus.
Conclusion
This study takes the opportunity to determinate the
main trends of teeth morphological changes of the Ur-
sus minimus. The specimens of this species from the
Early Ruscinian (Baróth-Köpec, Moiseevka) are char-
acterized by archaic tooth morphology and small size.
The members of U. minimus from the Late Ruscinian
are characterized by larger size of the teeth in compar-
ison to the Early Ruscinian ursids. All specimens of U.
minimus from the Late Ruscinian are very close to each
other in tooth sizes and their morphology (Kosyakino,
Wê¿e 1, Perpignan and possible Odessa Catacombs).
The largest tooth sizes are correlated with maximum
number of structures at the masticatory surface in the U.
minimus specimens from the Early Villányian (MN16;
Gaville and Kvabebi localities).
Despite considerable intraspecific variability of the
tooth features in bears, studied specimens of U. mini-
mus are morphologically similar. All variations ob-
served are typical for intraspecific variability in bears
and other omnivorous carnivores. Therefore there are
no solid reasons for subdivision of Ursus minimus into
a different species.
The detection of tendencies of the tooth apparatus
evolution in U. minimus was made on the basis of
European fossils material. However, the tendencies and
peculiarities of the evolutionary process in the Asiatic
part of the specific range stay indistinctive. The speci-
mens of U. minimus from Caucasus (Kosyakino, Kva-
bebi) correspond to the European trends. The specimen
from Kazakhstan (Moiseevka) possesses some pecu-
liarities in morphology of m1 talonid in contrast to the
specimens from Europe. The available specimens of U.
minimus from China (Dongxiang, Yinan) are character-
ized by retaining of plesiomorphic features (small tooth
sizes and the m1/m2 length ratio; Qiu et al., 2009).
Thus U. minimus is characterized by geographic
variability in its large specific range which covered the
most part of Eurasia. The geographic variability of the
species was well expressed during both the Early
Pliocene (U. m. boeckhi in Europe and U. m. ssp. in
Kazakhstan) and the Late Pliocene (U. m. minimus in
Europe and U. m. yinanensis in China).
ACKNOWLEDGEMENTS. The material for ex-
amination and comparison has been provided by Dr. V.
Eisenmann (NHMN), Prof. C. Guérin (CBUL), Dr. E.
Crégut-Bonnoure (RMA), Dr. L. Rook (IGF), Prof. R.
Ziegler (SMNS), Dr. H. Lutz (NMM), Prof. A. Nada-
chowski, Dr. P. Wojtal and Dr. G. Lipecki (ISEA), Dr.
M. Sabol and Dr. A. Durisova (SNMB). Dr. J. Wagner
(Prague) and G. Nazimbetova (Almaty) gave us valu-
able advices in preparing the paper and Dr. S. Barysh-
nikova (ZIN) assisted us in this study.
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