Washington: In a first, researchers have recreated in 3D the skull of the last common ancestor of Homo sapiens and the Neanderthals that lays bare open the "virtual fossil" for key evolutionary research.
Previous estimates based on ancient DNA have predicted the last common ancestor lived around 400,000 years ago.
However, results from the “virtual fossil” show the ancestral skull morphology closest to fossil fragments from the Middle Pleistocene suggests a lineage split of around 700,000 years ago.
The 'virtual fossil' has been simulated by plotting a total of 797 'landmarks' on the cranium of fossilised skulls stretching over almost two million years of Homo history.
It includes a 1.6 million-year-old Homo erectus fossil, Neanderthal crania found in Europe and even 19th century skulls from the Duckworth collection in Cambridge.
The landmarks on these samples provided an evolutionary framework from which researchers could predict a timeline for the skull structure, or 'morphology', of our ancient ancestors.
The virtual 3D ancestral skull bears early hallmarks of both species.
“For example, it shows the initial budding of what in Neanderthals would become the 'occipital bun' -- the prominent bulge at the back of the skull that contributed to elongated shape of a Neanderthal head,” the authors noted.
“We know we share a common ancestor with Neanderthals, but what did it look like? Many controversies in human evolution arise from these uncertainties," explained study's lead author Dr Aurelien Mounier, researcher at Cambridge University's Leverhulme Centre for Human Evolutionary Studies (LCHES).
The face of the virtual ancestor shows hints of the strong indention that modern humans have under the cheekbones, contributing to our more delicate facial features.
In Neanderthals, this area -- the maxillia -- is 'pneumatized', meaning it was thicker bone due to more air pockets, so that the face of a Neanderthal would have protruded.
The results were published in the Journal of Human Evolution.