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.
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,