jueves, 11 de junio de 2009
"Human"-Faced Missing Link Found in Spain?
With a face scientists call "surprisingly human"—and an artist-supplied enigmatic smile—this missing link Mona Lisa may represent the last common ancestor of humans and great apes.Discovered in Spain, the Anoiapithecus brevirostris ape species shares traits of both primitive apes and early human ancestors—and hints that the human-great ape lineage began in Europe, not Africa, according to a June 2009 study.
Move over Ida—you're last month's news. There's a new (purported) "missing link" in town.
An 11.9-million-year-old fossil ape species with an unusually flat, "surprisingly human" face has been found in Spain. The discovery suggests humans' ape ancestors split from primitive apes in Europe, not Africa—the so-called cradle of humanity—a new study says.
The species, Anoiapithecus brevirostris, may also represent the last known common ancestor of humans and living great apes—including orangutans, gorillas, and chimpanzees—researchers say.
"With this fossil, our opinion is that the origin of our family very probably took place in the Mediterranean region," said study leader Salvador Moyà-Solà of the Catalan Institute of Paleontology in Barcelona.
Unearthed at a fossil-rich site near Barcelona in 2004, the fragmented skull remains suggest a species with human-like facial features, Moyà-Solà said.
But a familiar face in and of itself doesn't mean the fossil "has any special specific relationship with modern hominds"—humans and the great apes—the paleontologist added.
Rather, the human-like face is evidence of great diversity among ape species in the Mediterranean region 12 million years ago, he said.
Resembling both primitive ape species and our early ancestors, Anoiapithecus could be called a missing link.
The ape's wide nose and long palate, for example, resemble those of the ancient apes from which great apes and humans arose, the study says.
But Anoiapithecus' thickly enameled teeth and robust jaw are like those of primitive Kenyapithecus fossil apes, which lived in both Africa and Europe, according to the team. Kenyapithecus species have been proposed as common ancestors of humans and great apes.
Until now, however, there hasn't been a fossil linking Kenyapithecus to later apes thought to have evolved into more direct human ancestors, according to the study, published last week in the journal Proceedings of the National Academy of Sciences.
The Spanish ape suggests this key evolutionary transition occurred after Kenyapithecus arrived in Europe from Africa some 15 million years ago—likely crossing over before the Mediterranean Sea formed, separating Africa from Europe—Moyà-Solà said.
"The 'folks' that migrated from Africa to the Mediterranean area were in fact completely primitive, without the [hominid] features that identify the members of our family," he said.
"The ancestors of gorillas, chimps, and humans then went back to Africa close to some nine million years ago."
There, they would give rise to the first humans, the thinking goes.
The new study isn't the first to hint at a European origin for hominids.
A similar theory has been advanced, for instance, based on 10- to 13-million-year-old fossils of the chimplike Dryopithecus group from France, Hungary, and Spain.
Anthropologist David Begun of the University of Toronto believes the evolution of African apes can be traced to Dryopithecus species that had migrated from Africa to Europe during the pre-Mediterranean Sea period.
"The new Spanish fossils do indeed support that hypothesis," said Begun, who was not involved in the new study.
However he "does not see any compelling evidence" linking Kenyapithecus with the newfound Spanish species.
"Frankly, [the new species] does not look like Kenyapithecus to me," he added.
Moyà-Solà, the study leader, doesn't rule out the possibility that each of the great ape species evolved independently from different Kenyapithecus species.
And it's possible that Africa could yet yield a species that, like the new Spanish ape, bridges the gap between early human ancestors and more primitive apes, he admitted.
"It's impossible to test our hypothesis [as of yet], because the fossil record in Africa from this period is very poor," Moyà-Solà said. "We need more and better fossils from Africa."
To that end, he said, the team's next major scientific stop will be somewhere south of the Mediterranean.