London, April 12 (Reuters): An international team of scientists have discovered 4.1 million-year-old fossils in eastern Ethiopia that fill a missing gap in human evolution.
The 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.
“This new discovery closes the gap between the fully blown Australopithecines and earlier forms we call Ardipithecus,” said Tim White, a leader of the team from the University of California, Berkeley.
“We now know where Australopithecus came from before 4 million years ago.”
The fossils were unearthed in the Middle Awash area in the Afar desert of Ethiopia. The area, about 230 km from Addis Ababa, has the most continuous record of human evolution, the scientists said.
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 which includes the famous fossil skeleton known as Lucy, which lived between 3.6 and 3.3 million years ago and was found in 1974.
“It is fair to say that some species of Ardipithecus gave rise to Australopithecus,” said White, who reported the discovery in the journal Nature.
He said the large teeth suggest the hominid was able to eat fibrous foods and roots.
The fossils from about eight individuals include the largest hominid canine found so far, the earliest known thigh bone of the species and hand and foot bones.
The finding also extends the range of Au. anamensis in Ethiopia. Previous remains of the species were found in Kenya.
, compared to earlier species of Ardipithecus that had smaller teeth which restricted their diet.
Along with the hominid fossils, the scientists discovered hundreds of remains of pigs, birds, rodents and monkeys as well as hyenas and big cats which gave them an idea of the habitat in which they existed.
”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,” White added.