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Illustration: Jay Matternes

BERKELEY — Nearly 17 years after plucking the fossilized tooth of a new human ancestor from a pebbly desert in Ethiopia, an international team of scientists today (Oct. 1) announced their reconstruction of a partial skeleton of the hominid, Ardipithecus ramidus, which they say revolutionizes our understanding of the earliest phase of human evolution.

The female skeleton, nicknamed Ardi, is 4.4 million years old, 1.2 million years older than the skeleton of Lucy, or Australopithecus afarensis, the most famous and, until now, the earliest hominid skeleton ever found. Hominids are all fossil species closer to modern humans than to chimps and bonobos, which are our closest living relatives.

"This is the oldest hominid skeleton on Earth," said Tim White, University of California, Berkeley, professor of integrative biology and one of the co-directors of the Middle Awash Project, a team of 70 scientists that reconstructed the skeleton and other fossils found with it. "This is the most detailed snapshot we have of one of the earliest hominids and of what Africa was like 4.4 million years ago."

White and the team will publish the results of their analysis in 11 papers in the Oct. 2 issue of the journal Science, which has Ardi on the cover. They announced their findings at press conferences held simultaneously today in Washington, D.C., and Addis Ababa, Ethiopia. >>Read more