LONDON: Ardi evolved from our common ancestor with chimpanzees and was equally at home walking on the ground and swinging through the trees. The remains of a woman who lived and died at the dawn of humanity have been uncovered in Ethiopia, providing the clearest picture yet of the origin of our species. The partial skeleton, the oldest from a human ancestor ever discovered, is that of a hairy female about 1.2 meters tall, with long arms, who walked on two legs but was adept at climbing trees and moving through the

forest canopy. She lived around 4.4 million years ago.

Experts have described the find as the most important regarding human evolution in the past century. The woman, nicknamed Ardi, belonged to a recently named species, Ardipithecus ramidus, and she could be the earliest discovered human ancestor who was capable of walking upright. The finding sheds light on a critical period of evolution at the root of the human family tree, shortly after our ancestors split from those of chimpanzees more than 6 million years ago.

Remnants of the skeleton, skull, pelvis, hands, feet and other bones were excavated from the sediments of an ancient river system near Aramis, northern Ethiopia, along with fragments from 35 other individuals.

Fossil hunters first glimpsed this species in 1992 when an Ardipithecus tooth was spotted among pebbles in the desert near Aramis. A two-year search was followed by a further 15 years’ work, involving 47 researchers. An in-depth description of the species, in 11 papers, appears today in the US journal Science.

Ardi weighed about 50kg, similar in weight to a living chimpanzee. But many of her features were far more primitive than those seen in modern apes, suggesting chimpanzees and gorillas have evolved considerably after splitting from the common ancestor they shared with humans.

The discovery of Ardi provides vital clues about the earliest

human ancestor that lived at the fork in the evolutionary road that led to humans on one side and chimps on the other.

“Darwin said we have to be really careful. The only way we’re really going to know what this last common ancestor looked like is to go and find it,” said Tim White, a lead author on the study and professor of human evolution at the University of California, Berkeley. “Well, we haven’t found it, but we’ve come closer than we’ve ever come, at 4.4m years ago.” The remains of animals, seeds and pollen at the excavation site reveal it to have been woodland where colobus monkeys swung in trees full of swifts, doves and lovebirds, and spiral-horned antelope, elephants, shrews and early forms of peacock roamed the forest floor

below.