Micro-CT scans have revealed the first evidence of an inner-ear structure that was previously thought to be a trait found only found in Neanderthals. Dr. Erik Trinkaus, physical anthropology professor at Washington University in Saint Louis, Xiu-Jie Wu, Wu Liu, and Song Xing of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, China, and Isabelle Crevecoeur of the Université de Bordeaux in France announced the discovery in the July 7, 2014, edition of the journal Proceedings of the National Academy of Sciences. The find further complicates the evolution of modern humans.
The shape of the temporal labyrinth of the inner ear of Neanderthals has been used a signature that a fossil had a Neanderthal origin since 1994. The identification was based on CT scans and has been found in the majority of Neanderthal skulls that have been unearthed. The human skull designated as Xujiayao 15 that lived about 100,000 years ago in China was found to have a temporal labyrinth like Neanderthals. Xujiayao 15 was originally found in 1979 along with sufficient evidence to define the remains as a modern human.
The discovery brings into question all accepted theories of Neanderthal and human migration, interbreeding, and the evolution of humans. The researchers point out that this find indicates that reliance on a limited number of fossils to construct broad based assumptions and theories about human evolution are no longer valid methods. The new fossil evidence destroys present ideas about mating between modern humans and Neanderthals as well as theories of the extinction of Neanderthals.
The discovery of a “typical” Neanderthal temporal labyrinth in an otherwise modern human questions the validity of using the temporal labyrinth as a defining characteristic of Neanderthals. The commonly held theory that modern man came out of Africa, mated with and produced the demise of the Neanderthal species, and then migrated into Asia is now a question. The new find is the first evidence of possible gene flow between European Neanderthals and early man in China. The development of an inner ear structure like Neanderthals had could have been an isolated genetic variation in one group of humans.