Meet the relative: man's earliest ancestor lived 7 million years ago

An ape-like creature who lived about 7 million years ago is almost certainly the earliest-known ancestor of humans, according to a study that could shed light on the identity of "Chad Man".

An ape-like creature who lived about 7 million years ago is almost certainly the earliest-known ancestor of humans, according to a study that could shed light on the identity of "Chad Man".

The discovery of the creature's fossilised remains in northern Chad in 2001 was hailed as the most important for 75 years as it appeared the remains had uniquely human traits.

Sceptics questioned whether the species was a hominid or an early ape, perhaps a female gorilla, but the scientists who made the original discovery say they have now found further fossils of Sahelanthropus tchadensis which confirms it as the earliest known ancestor of humans.

They have also performed a computer reconstruction of the creature's face which indicates that its features were more human than ape-like and suggest that it walked upright.

Professor Michel Brunet of the University of Poitiers said that Chad Man, nicknamed Toumai, which means "hope for life" in the local Goran language, possessed a unique combination of primitive ape-like features and more modern human traits.

Details of the new fossils - a jawbone and teeth - as well as the computer reconstruction of his face, are published today in the journal Nature . They suggest that Toumai lived soon after the human lineage diverged from the last common ancestor of man and chimpanzee, Professor Brunet said.

"[It] might have been an upright biped, suggesting bipedalism was present in the earliest known hominids, and probably soon after the divergence of the chimpanzee and human lineages," he said.

A graduate student at the University of N'Djamena in Chad, Ahounta Djimdoubmalbaye, found Toumai's fossilised skull in the Djurab desert in July 2001.

Professor Chris Stringer, head of human origins at the Natural History Museum in London, said in 2002 that the creature's brain size and skull shape were like an ape's but it had a flatter, more human, face and small teeth. However, others, notably Professor Milford Wolpoff, of the University of Michigan, said the skull was not human at all and more likely to be the head of a female ape. "Toumai may be a common ancestor of apes and humans, but it is not on the line directly leading to humans," Professor Wolpoff said.

When found, Toumai's skull had been squashed, but computer scans had enabled the researchers to produce a virtual, three-dimensional reconstruction of the creature's skull.

They found that the angle between the base of the skull, where the spinal cord enters the braincase, and the front plane of the face was similar to modern humans, and quite different to chimps and other apes which walk on all fours.

Toumai's fossils were found alongside the bones of many extinct animals such as three-toed horses, large wild boars, crocodiles and hippos, which have been dated accurately to living between 6 million and 7 million years ago.