Does This Neanderthal-like Ear on a More Modern Man Suggest Interbreeding?

A recent examination of a prehistoric skull, Xujiayao 15, has brought up the debate of interbreeding with Neanderthals again. The skull, discussed in greater detail here, was recently examined by Professor Erik Trinkaus of Washington University in St. Louis and colleagues, and they discovered something unexpected.

It is widely accepted that Neanderthals have a distinctive ear canal, or “temporal labyrinth”, which Trinkaus’ report describes as a relatively small anterior canal, a relatively larger lateral one, and a more inferior position of the posterior one relative to the lateral one. The Xujiayao 15 skull possessed this trait, but no other obvious Neanderthal traits to go along with it.

Vindija Cave is the Croatian site where Neanderthals lived about 30,000 years ago, and where a Neanderthal individual was selected as a DNA source for the Neanderthal genome project. A small number of scientists believe homo neanderthalensis should be reclassified as a subspecies of homo sapiens, “Homo sapiens neanderthalensis”, but they are generally considered to be their own species by most others.

The date of Neanderthal extinction is also under dispute thanks to fossil evidence found in Gorham’s Cave, a natural sea cave in Gibraltar. The generally accepted date is roughly 30,000 years ago, although there may be evidence that they existed up to 24,500. Either way, we know that Neanderthals existed alongside more modern humans for a long period of time. Recently, scientists released information about Neanderthal eating habits as mentioned in this Inquisitr article.

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Some evidence exists that suggests interbreeding between Neaderthals and Cro-Magnon man in populations throughout ancient Europe probably occurred. One such piece of evidence was found in a burial site at the Abrigo do Lagar Velho, Portugal. There, a 4 year old child’s fossils were buried, and after examination of the cranium, mandible, dentition and postcranian regions of the skull, traits of both modern man and Neanderthals were in evidence. More importantly, evidence to suggest the combined reproduction of the species are shown in a study of the Neanderthal genome, as discussed here.

Whether or not the Xujiayao 15 skull is evidence of interbreeding is a matter for debate. However Trinkaus had this to say, “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.”

[image via Wikimedia Commons/Dr. Mike Baxter]