TM 266-01-060-1 (Toumaï)

TM 266-01-060-1, "Toumaï", Sahelanthropus tchadensis

Discovered by Ahounta Djimdoumalbaye in 2001 in Chad, in the southern Sahara desert (Brunet et al. 2002, Wood 2002). Based on faunal studies, it is estimated to be between 6 and 7 million years old, and more likely in the older part of that range. This is a mostly complete cranium with a small brain (between 320 and 380 cc) comparable in size to that of chimpanzees.

No bones below the skull have been discovered yet, so it is not known whether Toumai was bipedal or not. Brunet et al. say that it would be a not unreasonable inference that it was a habitual biped because it shares characteristics with other hominids known to be bipedal. Other scientists have pointed out the foramen magnum (the hole through which the spinal cord exits the skull) of Toumai is positioned towards the back of the skull as in apes, indicating that the skull was held forward and not balanced on top of an erect body.

Brunet et al. consider Toumai to be a hominid, that is, on our side of the chimp-human split and therefore more closely related to us than to chimps. This is not at all certain. Some scientists think it probable; others have suggested that it may come from before the point at which the hominid and chimp lineages diverged, while Brigitte Senut (one of the discoverers of Orrorin tugenensis, "Millennium Man") has suggested that it may be an early gorilla. It is, I think, impossible to know how Toumai is related to us until other fossils can be found from the same time period.

Whatever it is, all scientists have been in agreement with its finders that Toumai is a find of major significance.

References

Brunet M., Guy F., Pilbeam D., Mackay H.T., Likius A., Djimboumalbaye A. et al. (2002): A new hominid from the upper Miocene of Chad, central Africa. Nature, 418:145-51.

Brunet M., Guy F., Pilbeam D., Lieberman D.E., Likius A., Mackaye H.T. et al. (2005): New material of the earliest hominid from the Upper Miocene of Chad. Nature, 434:752-5.

Wood B. (2002): Hominid revelations from Chad. Nature, 418:133-5.

Zollikofer C.P.E., Ponce de León M.S., Lieberman D.E., Guy F., Pilbeam D., Likius A. et al. (2005): Virtual cranial reconstruction of Sahelanthropus tchadensis. Nature, 434:755-9.

Links

Skull Fossil Opens Window Into Early Period of Human Origins, by D. L. Parsell (National Geographic News)

The Toumaï website (Centre National de la Recherche Scientifique)

Father of Us All?, by Michael Lemonick and Andrea Dorfman (Time)

Meet the Oldest Member of the Human Family, by Kate Wong (Scientific American)

New 'Ape-Man' Preliminary Response, by Carl Wieland (a creationist response)

Ancient skull more ape than human? (CNN)

This page is part of the Fossil Hominids FAQ at the talk.origins Archive.