Is 7-million-year-old skull really human?

Who or what was Toumai? Those who found his skull in 2001 insist he is the oldest human ancestor, a small fellow who lived by an African lake some 7 million years ago. Doubters have maintained that the skull belongs to an ancient chimpanzee or a gorilla.
More recent findings, announced last week (April 7), include teeth and jaw fragments unearthed in Toumai's neighborhood. Together with a reconstruction of his cracked skull, they support the idea that he was more man than ape.

When the skull was first found, Daniel Lieberman, a professor of anthropology at Harvard, called it "one of the greatest discoveries of the past 100 years." After studying the new evidence, Lieberman stands by that statement. "The next oldest, reasonably complete humanlike skull we have is just over 3 million years old," he notes. "The Toumai fossils go back close to the time when anthropologists believe our ancestors separated from chimpanzees."

In 2001, Michel Brunet, from the University of Poitiers in France, led a team who found the cracked and distorted cranium, along with two lower jaw fragments and some teeth, in a blisteringly hot, arid part of Chad, in north central Africa. The discovery pulled up the tree of evolution by its roots.

Brunet and his team named the creature Toumai, which means "hope of life" in the local language. It's a name often given to newborns in Chad. The fossils make him out to be about 3 to 4 feet tall, with thick brow ridges, and a flat, somewhat humanlike face. Close examination of the new teeth and jaw parts lead to the conclusion that they are of the same ancient age and belonged to creatures like Toumai.

The fossils are pictured and described in two articles in the April 7 issue of the journal Nature. The two reports are the product of an international collaboration among Brunet and his colleagues at the University of Poitiers; Lieberman; David Pilbeam, a professor of anthropology at Harvard; and researchers from the University of Zurich in Switzerland and from Chad.