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Science Forum Index » Anthropology - Paleo Forum » Afr;apes are derived
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| Author |
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| Marc Verhaegen |
 Posted: Sat Jun 02, 2007 11:09 am |
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Guest
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Rel.small canines, thick enamel & short-legged bipedality are primitive for
hominids-pongids & predate the Homo/Pan split:
An Ape or the Ape: is the Toumaļ Cranium TM 266 a Hominid?
PaleoAnthropology: 36-50
MH Wolfpoff, J Hawks, B Senut, M Pickford & J Ahern 2006
The Toumaļ cranium TM 266 is the first known from any Late Miocene African
hominoid clade, and is one of the best preserved crania of any Miocene
hominoid. Since its publication there has been debate in the scientific
literature and discussion in the popular press over the assertion that this
cranium is significant because it is the earliest known hominid1. The basis
of the hominid assessment rests on two interpretations of the anatomy: a
hominid-like, small, flat-wearing canine; and, cranial features reflecting
an upright stance and bipedal locomotion. In fact, it is widely reported
that the specimen is an upright hominid biped (Haile-Selassie et al.2004,
Kimbel 2004, Lieberman 2002), although this is yet to be verified by
independent observations and study. The history of paleo-anthropology may be
relevant to this assessment, because there have been similar claims for
other extinct primate species. Here, we evaluate the hypothesis that
Sahelanthropus (the genus TM 266 is attributed to) is a hominid by examining
features of the canine and of the cranial base that are said to reflect
canine reduction and change of function, and upright posture and bipedal
locomotion. These are hominid autapomorphies and their presence or absence
in late Miocene hominoids has fundamental importance for identifying the
hominid clade.
.... a number of Miocene ape canines evince wear surfaces with a similar
pattern (Figure 4). It is known in males and females of Ugandapithecus,
Afropithecus, Nacholapithecus, Kenyapithecus, Ouranopithecus,
Ankarapithecus, Oreopithecus & Sivapithecus. All these forms also show
apical wear of the canine crowns, and poorly developed C-P 3 honing
complexes, as reported in TM 266. In... Gigantopithecus and
Ouranopithecus,... the resemblance to the TM 266 condition is especially
marked.
.... the TM 266 cranial base is like all female gorillas ...
.... The temporal placement of Sahelanthropus is compatible with indications
that the ancestral condition for hominid dental evolution was more like
known Miocene apes than like chimpanzees. ... |
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