Fossil Sheds Light on Great Ape Ancestry

Researchers in Barcelona, Spain, say they have uncovered a relatively complete fossil of one of the earliest great apes, the category that includes human beings. A report published today in the journal Science describes the new species, Pierolapithecus catalaunicas, which lived between 12.5 million and 13 million years ago. Apes diverged from monkeys near the beginning of the Miocene epoch about 25 million years ago. As long ago as 19 million years ago, the great apes then parted ways with the lesser apes, a group that includes modern gibbons. Dozens of species of great apes lived during the Miocene, but only humans, chimpanzees, gorillas and orangutans remain.

The fossil includes parts of a skull that has a rather vertical face as well as other bones that show features characteristic of great apes. For example, the highly curved rib bones indicate that Pierolapithecus had a broad flat chest and its shoulder blades were on its back rather than on the sides of its chest, as in monkeys. These features, together with a flexible wrist joint, are thought to help in swinging from branches. Although the specimen has short fingers similar to those of monkeys, its discoverer, Salvador Moy�-Sol� of the M. Crusafont Institute of Paleontology, and his colleagues propose that long fingers like those of great apes may have evolved later. Like modern great apes, Pierolapithecus's lower back was short and stiff, which is suggestive of an upright posture.

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