CHICAGO —

French fossil hunters have pinned down the age of Toumai, which they contend is the remains of the earliest human ever found, at between 6.8 and 7.2 million years old.

The fossil was discovered in the Chadian desert in 2001 and an intense debate ensued over whether the nearly complete cranium, pieces of jawbone and teeth belonged to one of our earliest ancestors.

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;-If Toumai is truly an early human, that means that the evolutionary split between apes and humans occurred far earlier than previously thought.

And pinning down his age is key to redrawing the evolutionary map;-”The radiochronological data concerning Sahelanthropus tchadensis  is an important cornerstone both for establishing the earliest stages of hominid evolution and for new calibrations of the molecular clock,” Brunet wrote in a study which will appear in the March 4 edition of the Proceedings of the National Academy of Sciences.

“Thus, Sahelanthropus tchadensis testifies that the last divergence between chimps and humans is certainly not much more recent than 8 Ma million years ago.”

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