Geekathon, part five

In 2001, a fossil skull was discovered in the desert in Chad. It had a nearly complete cranium and some pieces of jawbone and teeth. Dubbed Toumai, it provoked an intense debate when its discoverers said it was a hominid - more exactly, if it was an early human. From the article:

Critics said that Toumai's cranium was too squashed to be that of a hominid - it did not have the brain capacity that gives humans primacy - and its small size indicated a creature of no more than 120 centimetres (four feet) in height, about the size of a walking chimp.

In short, they said, Toumai had no right to be baptised with French researcher Michel Brunet's hominid honorific of Sahelanthropus tchadensis - he was simply a vulgar ape.

Toumai's supporters used 3D computer reconstructions to show that the structure of the cranium had clear differences from those of gorillas and chimps and indicates that Toumai was able to walk upright on two feet, something our primate cousins cannot do with ease.

The argument just took on some added significance: The French team that found the fossil say they have determined its age to be between 6.8 and 7.2 million years old. So if it truly was an early human, the story of human evolution will have to be re-written because it will mean the split between apes and humans took place 500,000 to a million years earlier than previously believed.

If Toumai - the name means "hope of life" in the local Goran language - is accepted as a human, the implications are profound.

The fossil was found some 2,500 kilometers (1,500 miles) west of the Great Rift Valley. If that is still seen as humankind's ancestral home, it implies the early hominids ranged far wider from East Africa, and far earlier, than previously thought.

The discovery also implies hominids evolved quickly from apes after they split from a common primate ancestry.

Anatomically modern humans, homo sapiens, are generally believed to have appeared about 200,000 years ago.