for National Geographic News
Scientists working in Africa have discovered a Stone Age skull that could be a link between the extinct Homo erectus species and modern humans (interactive guide to human evolution from National Geographic magazine).
The face and cranium of the fossil have features found in both early and modern human species. The skull is believed to be between 250,000 and 500,000 years old.
"[This skull] shows the continuity of the evolutionary record, so in that sense it is a link [between Homo erectus and modern humans]," said Scott Simpson, a paleontologist from Case Western Reserve University School of Medicine in Cleveland, Ohio.
Researchers discovered the skull five weeks ago at Gawis in Ethiopia's northeastern Afar region (map of Ethiopia). The area is rich in fossil and archaeological deposits ranging from 10,000 years to 5.6 million years in age.
An international group known as the Gona Paleoanthropological Research Project began field research in the area in 1999.
Asahmed Humet, a local Afar tribesman working with project, found the early-human cranium in a small gully at the base of a steep slope of sediments.
The skull was missing a lower jaw but had a nearly intact cranium. Most early human fossils are found in many small pieces.
The scientists believe the skull comes from the middle Pleistocene era, about 600,000 to 200,000 years ago.
Homo erectus is thought to be an ancestor of modern Homo sapiens. H. erectus first appeared in Africa and lived from about 1.9 to 0.8 million years ago. (See photos and more from a recent H. erectus discovery in the republic of Georgia.)
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