Fossils belonging to an ape that lived 10 million years ago have been discovered in Ethiopia. They give clues to the evolution of our closest living relatives, the other great apes.
Scientists from Japan and Ethiopia uncovered the nine fossilised teeth in the Chorora Formation in the Afar region of Ethiopia. This area has revealed many fossil specimens from other ancient animals and a variety of techniques have dated them to the time of the Miocene, around 10 million years ago.
'The ancestry of humans is increasingly well known,' says Prof Peter Andrews, human evolution expert at the Natural History Museum. 'But the fossil evidence for the evolution of our closest living relatives, the great apes, is almost non-existent.'
'It is really exciting, therefore, to find a fossil ape from this time period. There is only one other fossil ape known from this time, the more complete Samburupithecus .'
Gen Suwa, from the University of Tokyo, and his team studied the fossil teeth using 3D analysis techniques. They found shearing structures on the molars, similar to those on teeth of modern-day gorillas. These structures allow gorillas to shred fibrous vegetation.
This finding, says Dr Suwa, suggests that the fossils belong to a new species of ancient ape in the gorilla group. This would mean the time period when the ancestor of gorillas split from a common human-ape ancestor must have been more than 10 million years ago, rather than the current thinking of around eight million years ago.
However, other scientists say these teeth structures occur not just in gorillas, but in other apes too. 'These structures appear on at least three independent lineages of apes, including gorillas,' says Prof Andrews. 'And they could relate to a dietary shift rather than indicating a new genetic trait.'
'It is stretching the evidence to base a time scale for the evolution of the great apes on this new fossil.'
These findings do, however, provide more data supporting the theory that humans and modern apes originated in Africa.
This research is published in the journal Nature.