Anthropologists have discovered the remains of the earliest known human ancestor in Ethiopia, dating to between 5.2 and 5.8 million years ago and which predate the previously oldest-known fossils by almost a million years. The previous discovery of the 4.4-million-year-old Ardipithecus ramidus was up to this point the oldest known hominid, the primate zoological family that includes all species on the human side of the evolutionary split with chimpanzees.
The fossil finds, reported in the July 12 issue of Nature, were made by National Science Foundation (NSF)-funded scientists over a four-year period in Ethiopia's Middle Awash study area, about 140 miles northeast of the capital, Addis Ababa. To the team of scientists, the discovery represents more evidence to confirm Darwin's conclusion that the earliest humans, or hominids, arose in Africa.
Yohannes Haile-Selaissie, a paleontologist at the University of California at Berkeley, made the recent fossil discoveries from these earliest creatures. Working under lead researcher and Berkeley colleague Tim D. White, Haile-Selaissie found a jawbone and teeth in December, 1997. More fossils were found, the last a tooth, uncovered in January, 2001.
The area where this hominid discovery took place has been the focus of much recent attention. Eleven hominid specimens have been recovered from five late Miocene localities within the Middle Awash region.
"The new fossils come from the oldest of the patches of exposed sediment at Saitune Dora, Alayla, Aas Koma and Digiba Dora," White said. "These bones and teeth were difficult to find on surfaces that are littered with stones ranging from pebbles to boulders."
The study of the Middle Awash has been ongoing since 1981
under the joint direction of White and Desmond Clark of UC-Berkeley, Giday WoldeGabriel of Los Alamos National Laborat
Contact: Bill Noxon
National Science Foundation