The
July 11, 2002 issue of Nature's feature article describes Sahelanthropus tchadensis
(nickname: Toumai, a new genus and species of the hominid clade. Based on associated
fossils, the six specimens found in Chad in Central Africa are believed to be
beween six and seven million years old. Because of both primitive and advanced
morphological features, the fossils suggest more diversity in the human lineage
than previously thought - rendering the antiquated concept of the "missing
link" to further invalidity. Sahelanthropus has many traits indicative of
hominids, such as smaller canines, and thicker tooth enamel than apes, and the
point at the back of skull where neck muscles attach suggests that Toumaï
walked upright. Many of these advanced features are missing from later fossils
such as Australopithecus, but reappear in still later species that are classified
in the genus Homo. The age of the fossils suggests than human and chimpanzee lineages
diverged earlier than indicated by most molecular studies.
Brunet,
M. et al. A new hominid from the Upper Miocene of Chad, Central Africa. Nature,
418, 145 - 151, (2002). Vignaud, P. et al. Geology and palaeontology of the
Upper Miocene Toros-Menalla hominid locality, Chad. Nature, 418, 152 - 155, (2002).
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