The discovery of modern Man's most ancient family member, whom scientists believe offers a crucial link between humans and chimpanzees, has provided proof of hominid life seven million years ago, according to two studies published on 11 July 2002 in the British journal Nature.

The groundbreaking discovery of Toumai - the nickname for the new hominid - was made by a French-Chad collaboration of paleontologists (MPFT) from 10 countries working in the Djurab desert of northern Chad.

The group, headed by Michel Brunet of France's University of Poitiers discovered the remains in 2001 and early 2002 - a nearly complete cranium, two lower jaw fragments and three isolated teeth - and used surrounding fauna to date it to nearly seven million years ago.

Their findings on Toumai, or Sahelanthropus tchadensis, indicate that the evolutionary split between chimpanzees and humans took place at early as seven million years ago, earlier than previous molecular studies indicated.

Toumai was probably the size of a chimpanzee, the studies indicate, with an ape-like braincase, but certain dental and cranial features including a prominent brow-ridge link him to the genus Homo.

Toumai's discovery holds the promise of a new perspective on the little-known period between five million years ago, when the last clear hominid traces appear, and 10 million years ago, when apes dominated.

"This will have the impact of a small nuclear bomb," Daniel Lieberman of Harvard University, one of several scientists to have seen the skull, was quoted in a Nature press release as saying.

Nature's paleontology editor Henry Gee said: "Toumai is arguably the most important fossil disovery in living memory."

Toumai's location - some 2500 kilometers (1550 miles) west of east Africa's Rift Valley, where other early hominids were found - has also prompted the scientists to rethink the belief in an exclusively east African savannah population in favor of a pan-African hominid presence.

The nickname Toumai, suggested by Chad authorities to the scientists, is a traditional name given in the Djurab desert to babies born on the eve of the dry season. It means "hope of life" in the local Goran language.

Brunel, who began research in central Africa some 20 years ago, co-authored the Nature articles with Patrick Vignaud, also of University of Poitiers.

David Pilbeam of Harvard University. Franck Guy of Harvard University and Mackaye Hassane Taisso of the University of N'Djamena in Chad were listed as researcher co-authors.