Inner Ear Formation Unique to Neanderthals Discovered in Ancient Human Skull

Researchers have discovered the presence of an inner-ear formation in an ancient human skull, initially thought to be present only in Neanderthals.

Micro-CT scans conducted by researchers at the Washington University in St. Louis on the fossilized human skull unearthed during a 1970s excavation, revealed the presence of an inner-ear formation. The human skull is approximately 100,000 years-old and was found at the Xujiayao site in china's Nihewan Basin.

"The discovery places into question a whole suite of scenarios of later Pleistocene human population dispersals and interconnections based on tracing isolated anatomical or genetic features in fragmentary fossils," said study co-author Erik Trinkaus, PhD, a physical anthropology professor at Washington University in St. Louis. "It suggests, instead, that the later phases of human evolution were more of a labyrinth of biology and peoples than simple lines on maps would suggest."

"We were completely surprised," said Erik Trinkaus, PhD, a physical anthropology professor at Washington University in St. Louis. "We fully expected the scan to reveal a temporal labyrinth that looked much like a modern human one, but what we saw was clearly typical of a Neandertal. This discovery places into question whether this arrangement of the semicircular canals is truly unique to the Neandertals."

Most often in the well preserved skull fossils of mammals, the semicircular canals are the remains of fluid-filled sensing system that aid humans in balancing when they alter their spatial orientation like running or turning the head from side to side.

Researchers earlier used the inner-ear structure as a marker to identify the human remains from Neanderthals and other hominid skeletons, according to Nature World News.

The fossilized skull has been dubbed Xujiayao 15 and was discovered among other human teeth and bone fragments with characteristics typical of early non-Neanderthals forms of late archaic humans.

This new find hints at migration patterns and possible interbreeding between the Neanderthals and early humans.

"The study of human evolution has always been messy, and these findings just make it all the messier," Trinkaus said. "It shows that human populations in the real world don't act in nice simple patterns.

The finding was documented in PNAS.