Spanish find provides lift to ancient ape.
The evolutionary affiliations of Dryopithecus, however, remain in dispute (SN: 10/23/93, p. 270). The scientists who unearthed the new specimen argue in the Jan. 11 Nature that it represents a direct ancestor of orangutans, an Asian ape. Other investigators familiar with the find assert that it may have served instead as a direct predecessor of African apes and hominids (members of the human evolutionary family), or perhaps even as a common ancestor of all later apes and hominids.
The newly unearthed bones, as well as a partial Dryopithecus skull previously found at the same site, apparently come from a single adult male, assert Salvador Moya-Sola and Meike Koehler of the Miquel Crusafont Istitute of Paleontology in Sabadell, Spain.
A number of lower-body features indicate that Dryopithecus favored climbing and swinging from one tree branch to another at a fairly slow pace, much in the fashion of modern orangutans, the Spanish researchers contend. The fossil creature has long arms and short legs relative to its estimated body size, a large hand with long, curved finger bones marked by grooves where powerful muscles attached, and a large clavicle resting atop a broad chest.
Moya-Sola and Koehler theorize that a common ancestor of all later apes and hominids existed well before Dryopithecus first appeared in Europe 12 million years ago. They speculate that Dryopithecus spawned a related extinct ape, Sivapithecus, whose fossils have been fond in Asia, and that it eventually led to modern orangutans.
In that case, Asian apes would have descended from Dryopithecus, evolving bodies built for slow climbing and hanging from branches, the scientists hold, whereas African apes veered toward a four-legged gait on the ground and hominids adopted an upright stance.
The Spanish Dryopithecus find indeed shows some similarities to orangutans, but its evolutionary position cannot yet be firmly established, assert Peter Andrews of the Natural History Museum in London and David Pilbeam of Harvard University in an accompanying commentary.
Some features of the Spanish skull and lower-body skeleton suggest a similarity to African apes and hominids rather than to orangutans, Andrews and Pilbeam maintain. For example, the body proportions of the new Dryopithecus specimen closely resemble the proportions of African apes, Pilbeam argues.
The Harvard investigator also argues that the shape of Sivapithecus arm bones differs substantially from those of Dryopithecus, indicating no direct evolutionary relationship between these ancient apes.
"The Spanish fossil is a wonderful find," Pilbeam remarks. "But I think it comes from a creature that was close to what the common ancestor of all [later apes and hominids] would have looked like."
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|Title Annotation:||Science News of the Week; researchers debate evolutionary affiliations of 9.5-million-year-old extinct ape Dryopithecus|
|Article Type:||Brief Article|
|Date:||Jan 13, 1996|
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