July 12th, 2002

"Swamp-Pig Man"
Sahelanthopus tchadensis discovery. The oldest hominid yet found, by faunal estimates dated between 6 and 10 mya, and possibly pre-dating the last common ancestor of Pan and Homo was discovered recently and published in Nature on July 11th 2002.

Although the evidence for its putative lifestyle was ambiguous, it certainly lived in a habitat which would have been consistent with a wading ape.

The so-called Mega Lake Chad was one thousand kilometres long when 'Toumai Man' (the official name given to it.
 

 Toumai means 'hope' in the local language) lived and the faunal remains found alongside him included many aquatic and amphibious animals including an abundance of Anthracotheriids or 'swamp pigs'. In fact there was so many of these fossils that the workers decided to name the whole member after them - The Anthracotheriid Unit (AU.)

Many hominids have been named because of their aquatic paleohabitats. Australopithecus anamensis was so named because it was found by a lake and so was "Turkana boy" and yet it still surprises some that our ancestry might have been profoundly influenced by water.

As to whether Sahelanthropus tchadensis turns out to support the AAH or not - the jury is still out. The local habitat also included some very arid places, including some of the earliest known sandy deserts. More than 50% of the fauna found appears to be similar to that found on open-grassland habitats today and there is even evidence for a type of dung-beetle.

The fossil evidence is always a matter of interpretation and it would appear that this finding in particular provides more ambiguities than clarifications.

What we can say is that it supports the aquarboreal (wading-climbing) model of bipedal origins then one would predict to find some evidence (such as a posterior foramen magnum) for bipedalism and relatively little evidence for knuckle-walking. This would suggest that the earliest hominoids were already bipedal before the Pan/Homo split and throw the cat among the pigeons about the notion that it only evolved on the Homo line.

So, it looks like we will just have to wait and see if 'Tomai Man' beomes 'Swamp Pig Man'.