Discovery of "Ardi" named breakthrough of the year

Washington, December 18 (ANI): The discovery of Ardipithecus ramidus, or "Ardi," has received the top honor as the Breakthrough of the Year 2009 by the magazine 'Science' and its publisher, AAAS, the world's largest science society.

The fossil of "Ardi," a hominid species that lived 4.4 million years ago, was unveiled on October 1 by Kent State University Professor of Anthropology Dr. C. Owen Lovejoy and his colleagues.

Their research findings on "Ardi", a small-brained, 110-pound (50-kilogram) female, are changing the way we think of human evolution.

The fossil puts to rest the notion, popular since Darwin's time, that a chimpanzee-like missing link-resembling something between humans and today's apes-would eventually be found at the root of the human family tree.

Indeed, the new evidence suggests that the study of chimpanzee anatomy and behavior-long used to infer the nature of the earliest human ancestors-is largely irrelevant to understanding our beginnings.

Ardi instead shows an unexpected mix of advanced characteristics and of primitive traits seen in much older apes that were unlike chimps or gorillas.

As such, the skeleton offers a window on what the last common ancestor of humans and living apes might have been like.

The biggest surprise about Ardipithecus's biology is its bizarre means of moving about.

All previously known hominids-members of our ancestral lineage-walked upright on two legs, like us.

But, Ardi's feet, pelvis, legs, and hands suggest she was a biped on the ground but a quadruped when moving about in the trees.

Ardipithecus's foot contains a special small bone inside a tendon, passed down from more primitive ancestors, that keeps the divergent toe more rigid.

Combined with modifications to the other toes, the bone would have helped Ardi walk bipedally on the ground.

The wrists and finger joints of Ardipithecus were highly flexible. As a result, Ardi would have walked on her palms as she moved about in the trees-more like some primitive fossil apes than like chimps and gorillas.

"What Ardi tells us is there was this vast intermediate stage in our evolution that nobody knew about," said Lovejoy. "It changes everything," he added. (ANI)