Pro
ton
, P
i Vir
ltad
nza
5,
di
Received 28 December 2005
Quaternary Research 68 (20Introduction
Bos is a common member of the Eurasian middle
Pleistocene–Holocene assemblages, but the oldest clear record
of this genus comes from Africa: the skull fragment ASB-198-1
from Asbole, Ethiopia (∼0.8–0.6 Ma) (Geraads et al., 2004a).
In Europe, the oldest evidence of Bos is at the site of Venosa-
Notarchirico, Italy (∼0.5–0.6 Ma), where it has been found
associated with the oldest Acheulean tools in Europe (Cassoli et
al., 1999). It is worth mentioning that an older record for this
genus was proposed with Bos galerianus from the site of Ponte
Galeria, Central Italy (~0.7–0.8 Ma) (Petronio and Sardella,
1998), but this species was later reassigned to Hemibos, a genus
of Indian origin, as Hemibos galerianus (Martínez-Navarro and
Palombo, 2004).
The genus Bos is characterized by a robust postcranial
skeleton and a highly derived cranial anatomy. The middle–late
Pleistocene and Holocene species B. primigenius has a robust
skull with elongated and hollowed frontals covering the parietal
bones and the nuchal crest. There is no preorbital fossa. The
premaxilla has a short contact with the nasal bones. The occipital
is low andwide. Amarked neck is present at the base of the horn-
cores, which are large, posterolaterally inserted and dorsoven-
trally compressed, with an oval cross-section that lacks keels,The origin of the genus Bos is a debated issue. From ∼0.5 Ma until historic times, the genus is well known in the Eurasian large mammal
assemblages, where it is represented by Bos primigenius. This species has a highly derived cranial anatomy that shows important morphological
differences from other Plio-Pleistocene Eurasian genera of the tribe Bovini such as Leptobos, Bison, Proamphibos-Hemibos, and Bubalus. The
oldest clear evidence of Bos is the skull fragment ASB-198-1 from the middle Pleistocene (∼0.6–0.8 Ma) site of Asbole (Lower Awash Valley,
Ethiopia). The first appearance of Bos in Europe is at the site of Venosa-Notarchirico, Italy (∼0.5–0.6 Ma). Although the origin of Bos has
traditionally been connected with Leptobos and Bison, after a detailed anatomical and morphometric study we propose here a different origin,
connecting the middle Pleistocene Eurasian forms of B. primigenius with the African Late Pliocene and early Pleistocene large size member of the
tribe Bovini Pelorovis sensu stricto. The dispersal of the Bos lineage in Western Europe during middle Pleistocene times seems to coincide with
the arrival of the Acheulean tool technology in this continent.
' 2007 University of Washington. All rights reserved.
Keywords: Bovini; Pelorovis; Bos; African originAbstractAvailable online 12 July 2007Short
The Olduvai buffalo Pelo
Bienvenido Martínez-Navarro
a,


, Juan An
Lorenzo Rook
d
a
ICREA, Area de Prehistòria-IPHES, Universitat Rovira
b
Departamento de Geología y Ecología (Área de Paleontología), Facu
c
Department of Earth Sciences, University of Roma “La Sapie
Piazzale Aldo Moro
d
Dipartimento di Scienze della Terra, Università

Corresponding author.
E-mail addresses: bienvenido@icrea.es (B. Martínez-Navarro),
Johnny@uma.es (J. Antonio Pérez-Claros), mariarita.palombo@uniromal.it
(M.R. Palombo), lorenzo.rook@unifi.it (L. Rook), ppb@uma.es (P. Palmqvist).
0033-5894/$ - see front matter ' 2007 University of Washington. All rights reserve
doi:10.1016/j.yqres.2007.06.002aper
vis and the origin of Bos
io Pérez-Claros
b
, Maria Rita Palombo
c
,
aul Palmqvist
b
gili. Plaça Imperial Tarraco, 1. 43005 Tarragona, Spain
de Ciencias, Campus Universitario de Teatinos. 29071 Málaga, Spain
”, and CNR Istituto di Geologia Ambientale e Geoingegneria,
00185 Roma, Italy
Firenze, via G. La Pira 4, 50121 Firenze, Italy
07) 220–226
www.elsevier.com/locate/yqresgoing a little backward, outward, forward and slightly upward.
Both sexes bear horn-cores but show an important degree of
sexual dimorphism. The largest B. primigenius specimens are
from the latemiddle Pleistocene and probably attained individual
bodymasses around 1500 kg, a figure close to the upper size limit
d.

of ruminants: above that size there is no advantage to foregut
fermentation in terms of digestive efficiency (Clauss et al., 2003).
The phylogeny of the tribe Bovini, based on the sequence of
nucleotides for the mitochondrial b gene, groups Bos with Bi-
son and separates both genera from other Asian and African
buffaloes such as Bubalus and Syncerus, respectively (Hassanin
and Douzery, 1999). However, although Bos and Bison show
important differences in the anatomy of the skull and
postcranium, their hybridization is possible (Polziehn et al.,
1995). The phylogeny of bovine species based on amplified
fragment length polymorphisms (AFPL) (Buntjer et al., 2002)
also shows a tree in which Bison and yak species (Bison bison,
Bison bonasus and Poephagus) and oxen (Bos taurus, Bos
indicus and Bos gaurus) are grouped separately, and also from
both Bubalus and Syncerus. In previous systematic classifica-
tions, however, some authors (e.g., Gentry, 1978; Groves, 1981)
considered Bos, Bibos, Bison and Poephagus as subgenera of
the genus Bos. Similarly, other researchers also included in this
group the Late Pliocene genus Leptobos, considering it also as a
subgenus (e.g., Brugal, 1985; Moyà-Solà, 1987).
The Bison lineage (including the extinct forms Bison
paleosinensis, Bison sivalensis, Dmanisibos georgicus, Eobi-
son, Bison meneri, Bison schoetensacki, Bison priscus and the
extant forms B. bison and B. bonasus)(Bukhsianidze, 2005),
based on skull anatomy, can be interpreted as resulting from
anagenetic evolution of the Late Pliocene forms of Leptobos
group of Leptobos elatus—ascribed to the subgenus Leptobos,
which is characterized by curved horn-cores that go backward,
outward and upward—and the group of Leptobos etruscus –
which she ascribed to a subgenus named Smertiobos, with
mostly elongated horn-cores going backward, a little outward
and finally a little inward. The cranial anatomy and the base of
the horn-cores are situated forward at the same point, however,
in both groups of Leptobos (see Fig. 1). Duvernois (1990)
proposes that a form of Leptobos (Leptobos)orLeptobos
falconeri from the Siwaliks (Pilgrim, 1939), which is in
connection with L. (Leptobos), is the ancestor of the Pleistocene
genera Bison, Bos and Bibos. The cranial anatomy of Bos,
however, is highly derived as to be considered the result of a
direct anagenetic evolution from any form of Leptobos.
Phylogeny of Bos
The African genus Pelorovis sensu stricto (considering the
Late Pliocene and early Pleistocene forms) is a taxon that has
never been considered within the framework of the evolutionary
history of Bos, although some cladistic studies included it
within the same group (e.g., Geraads, 1992). Pelorovis, evolved
from the Early Pliocene African form Simatherium (Gentry,
1967; Vrba, 1987), is known as the Olduvai buffalo because the
type species of this genus, Pelorovis oldowayensis (Reck, 1927)
was discovered at Olduvai (Tanzania) and redescribed by
Pel
nius
221B. Martínez-Navarro et al. / Quaternary Research 68 (2007) 220–226across the Plio-Pleistocene transition (∼2.0–1.7 Ma) (Fig. 1).
After Duvernois (1990) there are two lineages of Leptobos, the
Figure 1. Posterior and superior views of Pelorovis turkanensis (KNM ER 524);
II, from Gentry, 1967, Pl. 3 Fig. 1 and Pl. 1 Fig. 2, respectively); Bos primigeLeptobos elatus (Cast MB FP 18, Dusino, from Duvernois, 1990, Pl. 5 and 4, respe
(MZB 94-0843); and Bison bonasus (MZB 94-0960). Bos and Pelorovis have the b
bones and overhanging the parietooccipital area. This morphology is not present inGentry (1967). Pelorovis is recorded in Late Pliocene and early
Pleistocene large mammal assemblages of Africa, and also in
orovis oldowayensis (Pel II, posterior view, and Pel I, upper view, Olduvai Bed
(MP 60037); Bos taurus (THK-0453S MCPA2); Bos indicus (MZB 82-7702;ctively); Leptobos etruscus (IGF-612); Bison priscus (IGF-1024); Bison bison
ases of the horn-cores situated posteriorly, showing an elongation of the frontal
Bison and Leptobos.