Apes which flourished in savannahs of eastern Europe 7 million years ago had pre-human traits –– an international team of scientists has found
The last common ancestor we shared with chimps seems to have lived in the eastern Mediterranean – not in East Africa as generally assumed.
This bold conclusion comes from a study of Greek and Bulgarian fossils, suggesting that the most mysterious of all ancient European apes was actually a human ancestor, or hominin. However, other researchers remain unconvinced by the claim.
Go back 12 or more million years ago and Europe was an ape’s paradise. But, about 10 million years ago, environmental conditions deteriorated and the European apes began to disappear. Apes became largely confined to Africa, splitting there into gorillas, chimpanzees and humans.
At least, that’s what most researchers think happened. But in 2012, Nikolai Spassov at the National Museum of Natural History in Sofia, Bulgaria, and his colleagues reported the discovery of an ape tooth from Bulgaria that was just 7 million years old. It was, they said, the youngest European ape fossil yet found.
Very Ancient Greek
Spassov and his colleagues – including Madelaine Böhme at the University of Tübingen in Germany and David Begun at the University of Toronto, Canada – now think the tooth belongs to an ape called Graecopithecus that clung on in eastern Europe long after the other apes had disappeared from the continent. What’s more, the team says, Graecopithecus was no ordinary ape – it was a hominin.
Other than the Bulgarian tooth, Graecopithecus is known from just one fossil jawbone found near Athens in 1944. The fossil was reportedly unearthed as the occupying German forces were building a wartime bunker – although Spassov says the exact details of the story are unclear.
With so little fossil material to work with, Graecopithecus is the most poorly known of all European apes. This is not helped by the fact that the Greek jawbone – nicknamed El Graeco – has a heavily worn surface.
But Spassov and his colleagues have used a micro-CT scanner to peer into the jawbone of El Graeco, and found that the roots of one of the premolars are “fused” together in an unusual way.
“This condition is so far only known to occur regularly in hominins – pre-humans and humans,” Spassov says. “It is extremely rare in recent chimps.”
There are also hints from the jaw that Graecopithecus had relatively small canines – another hominin trait. Together, the two features suggest Graecopithecus may have been a hominin, the researchers say.
Signs of the times
In a complementary analysis, the team has also investigated the local geology in Greece and Bulgaria at the time to establish that Graecopithecus lived in exactly the sort of dry savannah-like environment traditionally thought to have driven early hominin evolution.
What’s more, geological dating techniques suggest it was alive between 7.18 and 7.25 million years ago – which means Graecopithecus slightly predates the oldest potential hominin found in Africa: Sahelanthropus is between 7 and 6 million years old.
Putting the pieces of the puzzle together, the team thinks that hominins might have split from the chimp evolutionary lineage in the eastern Mediterranean a little earlier than 7.25 million years ago. In other words, they say, that our last common ancestor with chimps may have been an eastern European.
David Alba at the Catalan Institute of Palaeontology in Barcelona, Spain says there is value to the new work: it provides convincing anatomical evidence that Graecopithecus is different from any other ancient ape found in Europe – something that wasn’t clear from earlier studies of the jawbone.
But he is less convinced by the idea that the tooth roots alone can confirm that Graecopithecus is a hominin. He says study co-author David Begun has been arguing for 20 years that the great apes first appeared in Europe. “It is not surprising at all that Begun is now arguing that hominins as well originated in Europe.”
Bernard Wood at George Washington University in Washington DC says the “hominin teeth” claim is relatively weak. “This would not be a character I would want to hang my hat on,” he says.
Read more at New Scientist