An upright hominid that lived side by side with direct ancestors of modern humans more than a million years ago had a far more diverse diet than once believed, clouding the notion that it was driven to extinction by its picky eating habits as the African continent dried, says a new University of Colorado at Boulder study.
The new study shows that Paranthropus robustus, once thought to be a "chewing machine" specializing in tough, low-quality vegetation, instead had a diverse diet ranging from fruits and nuts to sedges, grasses, seeds and perhaps even animals, said CU-Boulder anthropology Assistant Professor Matt Sponheimer. The findings cast doubt on the idea that its extinction more than 1 million years ago was linked to its diet, he said.
Paranthropus was part of a line of close human relatives known as australopithecines that includes the famous Ethiopian fossil Lucy that lived over 3 million years ago. Lucy is regarded by many anthropologists as the matriarch of modern humans.
"One line of Lucy's children ultimately led to modern humans while the other was an evolutionary dead end," he said. "Since we have now shown Paranthropus was flexible in its eating habits over both short and long intervals, we probably need to look to other biological, cultural or social differences to explain its ultimate fate."
A paper on the subject appears in the Nov. 10 issue of Science. Co-authors include the University of Utah's Benjamin Passey and Thure Cerling, Texas A&M University's Darryl de Ruiter, Ohio State University's Debbie Guatelli-Steinberg and Julia Lee-Thorp of the University of Bradford in Bradford, England.
Roughly 2.5 million years ago, the australopithecines are thought to have split into the genus Homo -- which produced modern Homo sapiens -- and the genus Paranthropus, Sponheimer said. Paranthropus stood about four feet tall and probably weighed less than 100 pounds, and its pelvis and leg structu
Contact: Matt Sponheimer
University of Colorado at Boulder