Fossil Finds Expand Early Hominid Anatomy

Article excerpt

Fossil finds expand early hominid anatomy

Renewed field research at the Ethiopian site of Hadar, where "Lucy" and other members of the earliest known hominid species turned up in the mid-1970s, has yielded a new batch of fossils that significantly expand the anatomical diversity of the more than 3-million-year-old species.

The finds, announced last week by project co-leaders Donald C. Johanson, William H. Kimbel and Robert C. Walter of the Institute of Human Origins in Berkeley, Calif., promise to reignite debates over whether Lucy and her cohorts represent one species or two, and whether at least some members of the species spent more time in trees than walking upright.

During two months of field exploration that began last October, a 10-member scientific team from the United States and Ethiopia found 18 fragmentary fossils that represent 15 individuals belonging to Lucy's species, Australopithecus afarensis. The specimens lay on the surface of heavily eroded layers of fossil-rich earth.

"We found fossil remains of hominids [the evolutionary family that includes modern humans] throughout the geologic horizon at Hadar," says Johanson, who led the team that discovered Lucy. "There should be many more to come in future field work."

A total of 15 tooth and jaw fragments possess characteristics similar to previous A. afarensis finds, but three fossils show anatomical features new to the Hadar hominid collection.

A specimen consisting of an upper jaw and partial face has bony pillars on each side of the nasal opening that resemble those of A. africanus, a South African hominid dating to at least 2.5 million years ago. …