Posted on Friday 24 October 2003

An international team of fossil hunters is reporting today the discovery of the world's earliest known "near-modern" humans -- a thickly muscled subspecies of Homo sapiens who used stone tools to butcher hippopotamus and buffalo by the shores of an ancient African lake.

UC Berkeley's Tim D. White and colleagues found the well-preserved, 160,000- year-old fossilized skulls of two adults and a child, along with skull fragments and teeth of seven other individuals, in 1997 while combing a fossil- rich area of Ethiopia about 140 miles northeast of the capital, Addis Ababa.

Missing link

The discovery, reported today in the journal Nature, fills an important gap in the evolutionary sequence between earlier pre-human ancestors, known as Homo erectus, and our own species. The latest find is about 60,000 years older than the oldest known specimen of Homo sapiens. The facial bones suggest strikingly modern features, although these early humans would be somewhat bigger and stronger than nearly anyone alive today. White said the discovery offers the best evidence so far of what our immediate ancestors must have looked like 100,000 to 300,000 years ago, "a period of time for which we had virtually no evidence."

Just how and where the human species emerged is still hotly debated. Some experts hold to a "multiregional" theory, which suggests human evolution followed many paths simultaneously in different parts of the world, including the Neanderthal lineage arising in Europe.

But White said this latest find offered strong support for the now-dominant "out of Africa" idea, which holds that our ancestors showed up first in Africa and then spread throughout the world. Neanderthals, by this argument, were a side branch that went extinct rather than an important component of the human rootstock.

"The African fossil record is pretty clear now in its message: Our species, Homo sapiens, evolved in Africa," White said.

Independent experts, including some multiregional theorists who disagreed with White's conclusions, said the new find ranked among the most significant fossil discoveries of recent years.

"It fills in an almost empty space in our knowledge of human evolution," said anthropologist John Hawks at the University of Wisconsin at Madison, in an e-mail exchange. "There are very few fossils from Africa during the time that the distinctive characteristics of recent people were evolving, and none can be placed in time as well as these remains."

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