Ancient Jawbone Could Shake Up Fossil Record

Nick Wadhams in Nairobi, Kenya
for National Geographic News
July 13, 2007

Jawbones from an early human ancestor, found recently in northeast Ethiopia, could shine light on a murky period of human evolution, paleontologists say.

The bones were found in the fossil-rich Afar region, just 20 miles (32 kilometers) north of the spot where the famed skeleton of "Lucy"—early human ancestor who lived 3.2 million years ago—was unearthed in 1974. (What was Lucy?)

The new bones are believed to date from 3.8 million to 3.5 million years ago.

Bridging the Gap

Though more research needs to be done, the group says the bones could bridge the gap between two known human ancestor species.

Australopithecus anamensis lived some 4.2 million to 3.9 million years ago, and Australopithecus afarensis—the species to which Lucy belonged—thrived from 3.6 million to 3 million years ago. (Explore our human roots through the Genographic Project.)

Some researchers believe that Lucy and others of her species were descendants of A. anamensis—and these new Ethiopian jawbones could end that speculation. (See map of Ethiopia.)

"This will help us test this very hypothesis and see if we can falsify it or prove it," said Yohannes Haile-Selassie, one of the lead researchers on the project and head of physical anthropology at the Cleveland Museum of Natural History in Ohio.

"We have had isolated teeth and [other skeleton parts] from previous years. What we didn't have was a complete jaw, which we have now," he said.

Along with the jawbone, the team has also uncovered more than 30 or 40 specimens to further test the hypothesis, Haile-Selassie noted.

Teeth Truths

Finding a complete jawbone is crucial in determining how a human ancestor developed. (Related: "Dental Detectives Reveal Diet of Ancient Human Ancestors" [November 9, 2006].)

Continued on Next Page >>




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