Ancient 'Nutcracker Man' challenges ideas on evolution of ...( Tiny marks on the teeth of an ancien...)

Tiny marks on the teeth of an ancient human ancestor known as the "Nutcracker Man" may upset current evolutionary understanding of early hominid diet.

Using high-powered microscopes, researchers looked at rough geometric shapes on the teeth of several Nutcracker Man specimens and determined that their structure alone was not enough to predict diet.

Peter Ungar, professor of anthropology at the University of Arkansas in Fayetteville, contends the finding shows evolutionary adaptation for eating may have been based on scarcity rather than on an animal's regular diet.

"These findings totally run counter to what people have been saying for the last half a century," says Ungar. "We have to sit back and re-evaluate what we once thought."

Ungar and his colleagues, Frederick E. Grine of State University of New York at Stony Brook and Mark F. Teaford of Johns Hopkins University, Baltimore, Md., reported their findings last week in the Public Library of Science One, a peer-reviewed, international, online journal. The research was funded in part by the National Science Foundation.

The researchers examined the teeth of Paranthropus boisei, an ancient hominin that lived between 2.3 and 1.2 million years ago and is known popularly as the "Nutcracker Man" because it has the biggest, flattest cheek teeth and the thickest enamel of any known human ancestor.

"Ungar and colleagues' work on Paranthropus boisei diet is extremely important," says Joanna Lambert, physical anthropology program director at NSF. "Understanding what and how early hominins ate sheds light not only onto the feeding biology of our fossil ancestors, but also onto the very evolution of our own species."

Scientists long have believed that P. boisei fed on nuts and seeds or roots and tubers found in the savannas throughout eastern Africa because the teeth, cranium and mandible appear to be built for chewing and crunching hard objects.

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