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.
(Read National Geographic magazine editor Chris Sloan's take on how another ancient-ape discovery in Europe by a team led by Begun fits into the debate.)
"The new Spanish fossils do indeed support that hypothesis," said Begun, who was not involved in the new study and whose work has been partially funded by the National Geographic Society's Committee for Research and Exploration. (The National Geographic Society owns National Geographic News.)
However Begun "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.
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