A bit of a jawbone (and a bit of computer modeling) has given us a long-awaited glimpse of our new oldest ancestor:
On 29 January 2013, scientists combing a stretch of northeastern Ethiopia’s Afar region found a 2.8-million-year-old jawbone that may belong to the earliest of the Homo species — perhaps the first ancient human. Its teeth are small, like those of other Homo species, and the parabolic shape of the jaw is a better match to Homo than to Australopithecus, says Brian Villmoare, a palaeoanthropologist at the University of Nevada Las Vegas. His team reports the discovery in Science. The researchers stopped short of putting a species name to the jaw — until they discover more remains. “We have every intention of finding them, but that’s just down to luck,” says Villmoare.
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But Homo‘s origins are increasingly confusing, as a reanalysis of 1.8-million-year-old fossil specimens, reported in Nature, demonstrates. In the early 1960s, a team led by palaeoanthropologists Louis and Mary Leakey found a deformed lower jaw, hand and partial skull in Olduvai Gorge, Tanzania.
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The Leakey team later designated the remains as a new species that they called Homo habilis, meaning the handy man.They contended that members of the species had made stone tools that had been discovered nearby years earlier.
But the material was so sparse that all manner of other fossils were later designated H. habilis.
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Reconstructing the broken pieces revealed that the jaw was more primitive-looking than the team expected. It was long and thin, and the rows of teeth on opposite sides were nearly parallel — more like an Australopithecus’s jaw than a human’s rounder one. A reconstruction of the skull bones, however, revealed that the brain was larger than expected, similar in size to that of H. erectus.
Previously discovered upper-jaw fossils classed as H. habilis, and dating back as far as 2.3 million years ago, look too different from the newly reconstructed jaw to belong to the same species….
So, you know, people. Always different. Even more different back then than now.