Meet Ardi, our 4 million-year-old grandma

Published on Thursday 1 October 2009 22:18

FOSSIL remains of a short human-like creature that lived 4.4 million years ago could be the closest thing yet to the legendary "missing link".

The almost intact female hominid skeleton, unearthed from a desert in Ethiopia, is the oldest-known human-like skeleton, writing a new chapter in human evolution.

Ardipithecus ramidus, nicknamed "Ardi" by scientists, possessed a bizarre amalgam of human and ape or monkey traits.

Experts believe she stood about 4ft tall and walked on two legs some of the time, while also living in trees.

However, scientists were surprised to discover that her anatomy was very different from that of present-day chimpanzees. Ardi lacked the acrobatic ability of the modern-day apes and did not swing or hang from branches. Instead, she would have climbed carefully on all fours, grasping with her long hands and feet.

Her face was more vertical and human-like than a chimp's, having a jaw that jutted out less, and lacked sharp, dagger-like canine teeth. She is believed to have been omnivorous, eating berries, fruits and roots as well as small mammals.

Ardi is also thought to have had a back that was long and curved like that of a human, rather than short and stiff like a chimpanzee. Humans and chimpanzees are believed to share an as-yet undiscovered common ancestor, which lived between about five and seven million years ago.

Professor Tim White, of the University of California at Berkeley, one of the authors who described Ardi in the journal Science, said she was neither chimpanzee nor human. He added that Charles Darwin was "very wise" on the subject of human origins, warning of the dangers of making rash assumptions about our heritage.

"Darwin said we have to be really careful," said Dr White. "The only way we're really going to know what this last common ancestor looked like is to find it. Well, at 4.4m years ago we found something pretty close.

"And evolution of the ape lineages and the human lineage has been going on independently since the time those lines split, since that last common ancestor we shared."