The Ancient Ancestor that Links Humans and Neanderthals: New Virtual Fossil (VIDEO)

First Posted: Dec 21, 2015 09:12 AM EST

Could we have found the last common ancestor of humans and Neanderthals? Scientists have used new digital techniques to predict the structure of evolution in the lineage of Homo sapiens and Neanderthals in order to better understand what our ancient ancestor looked like.

We share a common ancestor with Neanderthals, which is the extinct species that were our closest prehistoric relatives. But scientists have long wondered what this ancient ancestor looked like. This is because fossil from the Pleistocene period are extremely scarce and fragmentary.

In this latest study, the researchers simulated the "virtual fossil" by plotted a totally of 797 "landmarks" on the cranium of fossilized skulls stretching over almost two million years of Homo history-including a 1.6 million-year-old Homo erectus fossil, Neanderthal crania found in Europe and even 19^th century skulls from the Duckworth collection in Cambridge.

The landmarks on the samples provided an evolutionary framework from which researchers could predict a timeline for the skull structure, or "morphology" of our ancient ancestors. They then feed a digitally scanned modern skull into the timeline, warping the skulls to fit the landmarks as they shifted through history.

In this case, the researchers found that the morphology of these skulls converged during the Middle Pleistocene, which is about 800,000 to 100,000 years ago. In all, the scientists generated three possible skull shapes that corresponded to three different predicted split times between the two lineages.

"We know we share a common ancestor with Neanderthals, but what did it look like" said Aurelien Mounier, one of the researchers, in a news release. "And how do we know the rare fragments of fossil we find are truly from this past ancestral population? Many controversies in human evolution arise from these uncertainties."

The new, virtual 3D ancestral skull bears the early hallmarks of both species. For example, it shows the initial budding of what in Neanderthals would become the "occipital bun," which is the prominent bulge at the back of the skull that contributed to elongated shape of a Neanderthal head. The face also shows hints on the strong indentation that modern humans have under the cheekbones, contributing to our more delicate facial features.

The findings reveal a bit more about what our ancient ancestor may have looked like. This, in particular, is important when it comes to better understanding how our own species evolved.