Researchers from Washington University in St. Louis discovered a 100,000-year-old human skull that contained an inner-ear structure similar to a Neanderthal's. The discovery of this inner ear structure may alter previous beliefs related to human evolution.
"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," said co-author Erik Trinkaus, a prominent paleoanthropologist and expert on Neanderthal biology and human evolution, in a university press release. He is also a professor at Washington University in St. Louis.
The study focused on micro-CT scans, which featured the interior design of a temporal bone inside the fossilized skull found in Xujiayao, Northern China 35 years ago.
The skull, dubbed the Xujiayao 15, was discovered with a few other relics of bone fragments and human teeth. All of these fossils were found to be similar to the appearance of archaic human beings, similar to early non-Neanderthals.
Semicircular canals - remnants of a fluid-filled hearing system - were well-preserved when discovered by researchers. This hearing system also helped in coordination, balance and spatial orientations.
Since the 1990s, researchers have been conducting CT scans to prove the existence of this curved structure. The team observed a pattern that resembled a labyrinth in these semicircular structures, a characteristic predominant in Neanderthal fossils.
Trinkaus studied Neanderthal fossils collected from different parts of the globe. He explained that these findings added to the confusion associated with explaining human evolution in the scope of biology, interbreeding and migration patterns.
Trinkaus explained his team expected the temporal labyrinth would resemble that of a modern human being when they first unearthed the fossil. Instead, they saw that it closely resembled a Neanderthal.
"This discovery places into question whether this arrangement of the semicircular canals is truly unique to the Neandertals," Trikaus added.
Further details of the study were published in the July 8 issue of Proceedings of the National Academy of Sciences.
