An ape that lived 13 million years ago in what is now Spain may have been the last common ancestor of all apes, including chimpanzees, gorillas, orangutans and humans, researchers said today.
The fossil provides a missing link, not directly between humans and an apelike ancestor, but between great apes and lesser apes such as gibbons, the researchers said.
The creature, named Pierolapithecus catalaunicus, had a stiff lower spine and flexible wrists that would have made it a tree-climbing specialist, the researchers write in this week's issue of the journal Science.
"This probably is very close to the last common ancestor of great apes and humans," said Mr Salvador Moya-Sola of the Miguel Crusafont Institute of Paleontology in Barcelona, Spain , who led the study.
It would have looked something like a modern chimpanzee and probably ate fruit, said his colleague Ms Meike Kohler.
"It may have looked a little bit in the face comparable to that of a chimp but with some differences," she said in a telephone briefing.
"I would call it a missing link, because it really fills a gap," she added.
About 25 million years ago, old world monkeys, which now live in Africa and Asia, split off from the line that eventually led to apes.
The great apes, orangutans, chimpanzees, bonobos, gorillas and humans, are believed to have branched off from the lesser apes such as gibbons and siamangs about 11 million to 16 million years ago.
Humans branched off from chimpanzees an estimated 7 million years ago.
The researchers had just begun digging at the site near Barcelona when a bulldozer turned up the first bits of the fossilized skeleton. They immediately knew they had something unique.
The animal's rib cage, spine and wrist all looked like a great ape 's, specialized for climbing. Monkeys, in contrast, while excellent climbers, have more general movement abilities and are not so specialized.
But the new find has small hands, unlike modern great apes.
"This newly discovered fossil, a new ape species from Spain called Pierolapithecus catalaunicus, or its close relative, may have been the last common ancestor of all living great apes, or close to that ancestor," said Brooks Hanson, deputy editor for physical sciences at Sciencemagazine.
"Although this group includes humans, it's important to remember that we've had millions of years of evolution since then", she added.