(Image: Philipp Gunz, Simon Neubauer & Fred Spoor)
Meet the digital handy man. This is a reconstruction of the skull of one of the first known members of the human genus, Homo habilis, which means "handy man", from about 1.8 million years ago.
The original fossil from Tanzania, which was first reported in 1964, is incomplete, consisting of just a few distorted fragments, coloured in the image above. But now a computer reconstruction has realigned the distorted fragments and filled in the missing parts, making it possible to compare the skull with other fossils from what was a critical time for early human evolution.
Three different Homo species existed between 2.1 and 1.6 million years ago: Homo erectus and Homo rudolfensis, as well as H. habilis.
The skull reconstruction caused a stir this week because it implied that these three hominids might have had older evolutionary roots than we thought.
It looks more primitive than much older remains from what was, until just this week, thought to be oldest bit of Homo we had – a fossil from Ethiopia from 2.3 million years ago called AL 666-1.
This means AL 666-1's owner couldn't have been an ancestor of H. habilis, and any joint ancestor must have been from much earlier.
The digitally reconstructed skull above shows the handy man shared some features with H. erectus, but in other ways resembled Australopithecus afarensis (the infamous "Lucy"), which lived some 3.2 million years ago.
Convenient find
This idea is backed up by another study published this week. It presented evidence of an even older Homo fossil – now the oldest known fossil from our genus. Dated to 2.8 million years ago, it was found in 2013 at the Ledi-Geraru site in Ethiopia and brings us the closest yet to our genus's split from the more ape-like Australopithecus.
"By digitally exploring what H. habilis really looked like, we could infer the nature of its ancestor, but no such fossils were known," says Fred Spoor from University College London, lead author of the reconstruction study, published in the journal Nature. "Now the Ledi-Geraru has turned up as if 'on request', suggesting a plausible evolutionary link between Australopithecus afarensis and Homo habilis."
Journal references: Nature, DOI: 10.1038/nature14224; Science, DOI: 10.1126/science.aaa1343
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