Anthropologists are surprised by the presence of a unique inner-ear formation – long thought to occur only in Neanderthals – in an early human skull, dating back as far as 100,000 years and found at the Xujiayao site in Nihewan Basin, China.
A reconstruction of Neanderthal man. Image credit: Neanderthal Museum.
“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 Prof Erik Trinkaus of Washington University in St. Louis, who, along with his colleagues, reported the discovery in the journal Proceedings of the National Academy of Sciences.
“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.”
The early Homo skull at the center of the study, known as Xujiayao 15, was discovered in 1979 along with an assortment of other human teeth and bone fragments, all of which seemed to have characteristics typical of a non-Neandertal form of late archaic humans.
The Xujiayao 15 late archaic human temporal bone from northern China with the extracted temporal labyrinth superimposed on a view of the Xujiayao site. Image credit: Institute of Vertebrate Paleontology and Paleoanthropology / Chinese Academy of Science.
Prof Trinkaus and his team re-examined the Xujiayao 15 skull using an industrial computed tomography (CT) scanner.
“We were completely surprised. 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 Neanderthal,” Prof Trinkaus explained.
“This discovery places into question whether this arrangement of the semicircular canals is truly unique to the Neanderthals.”
_____
Xiu-Jie Wu et al. Temporal labyrinths of eastern Eurasian Pleistocene humans. PNAS, published online July 07, 2014; doi: 10.1073/pnas.1410735111
