Fossil ape makes evolutionary debut.

A roughly 13-million-year-old partial skeleton unearthed in northeastern Spain comes from a creature that, according to its discoverers, was a key evolutionary precursor of chimpanzees, gorillas, orangutans, and people.

A team led by Salvador Moya-Sola of the Miguel Crusafont Institute of Paleontology in Barcelona has assigned the find to a new genus and species, Pierolapithecus catalaunicus.

The spotty fossil record of apes that lived between 25 million and 5 million years ago consists mostly of jaw and skull fragments as well as isolated teeth. The new find is made up of an unprecedented variety of bones from a shoulder, and the face, chest, legs, hands, wrists, and upper jaw, including many teeth.

P. catalaunicus weighed around 75 pounds and was well suited for tree climbing, much in the style of later apes, the scientists report in the Nov. 19, 2004 Science. In particular, they say, the ancient ape's broad rib cage resembles rib cages of modern-day apes and would have facilitated the flexible arm movements needed for climbing.

In contrast, the relatively short, straight finger bones in the Spanish find bear a strong resemblance to the digits of living monkeys, Moya-Sola's group asserts. P. catalaunicus apparently moved through trees without swinging from branch to branch as apes now do, the researchers conclude.

Further excavations need to establish whether this ancient ape also inhabited Africa, where many anthropologists theorize that the first apes emerged.