Fossils fill evolutionary gap

2006-04-17 17:22

London - An international team of scientists have discovered fossils in eastern Ethiopia that fill a missing gap in human evolution.

The 4.1m-year-old teeth and bones belong to a primitive species of Australopithecus known as Au anamensis, an ape-man creature that walked on two legs.

The Australopithecus genus is thought to be an ancestor of modern humans.

Seven separate species have been named. Au anamensis is the most primitive.

Tim White, part of the University of California team researching the fossils, said: "This new discovery closes the gap between the fully blown Australopithecines and earlier forms we call Ardipithecus.

"We now know where Australopithecus came from before 4m years ago."

Fossils unearthed in Ethiopia

Found and analysed by scientists from the United States, Ethiopia, Japan and France, the fossils were unearthed in the Middle Awash area in the Afar desert of eastern Ethiopia.

According to the researchers, the area - about 230km northeast of the Ethiopian capital Addis Ababa - has the most continuous record of human evolution.

The remains of the hominid that had a small brain, big teeth and walked on two legs, fits into the one million-year gap between the earlier Ardipithecus and Australopithecus afarensis.

The Australopithecus afarensis includes the famous fossil skeleton "Lucy", who lived between 3.6 and 3.3m years ago and was found in 1974.

White, who reported the discovery in the journal Nature, said: "It is fair to say that some species of Ardipithecus gave rise to Australopithecus."

The fossils are from eight individuals, and include the largest hominid canine found so far, as well as the earliest known thigh bone of the species and hand and foot bones.

Remains of pigs also found

The finding also extends the range of Au anamensis in Ethiopia. Previous remains of the species were found in Kenya.

White said the large teeth suggest the hominid was able to eat fibrous foods and roots, compared to earlier species of Ardipithecus that had smaller teeth which restricted their diet.

Along with the hominid fossils, scientists discovered hundreds of remains of pigs, birds, rodents and monkeys as well as hyenas and big cats.

This gave them an idea of the habitat in which the Au anamensis existed.

White said: "Here, in a single Ethiopian valley, we have nearly a mile-thick stack of superimposed sediments and twelve horizons yielding hominid fossils.

"These discoveries confirm the Middle Awash study area as the world's best window on human evolution."

- Reuters