Dental News - Fossil mandible points to complexity of Neanderthals’ origin

Dental Tribune International

Wed. 24. January 2018

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BURGOS, Spain: There are many scientists arguing that the Neanderthal lineage evolved linearly. However, a paper by a team of researchers from the Centro Nacional de Investigación sobre la Evolución Humana in Burgos in Spain has been refuting this hypothesis, revealing the true complexity of the origin of the Neanderthals. The study reassesses a mandible found in France in the twentieth century.

The mandible was discovered on 18 June 1949 in the La Niche cave in Montmaurin, where stone tools and fossil remains of different species of canids, equids and ursids also appeared, helping to place it in time. The presumed age of this mandible, between 200,000 and 240,000 years, had led to the supposition of a close morphological similarity to the mandible of European Neanderthals, particularly in the teeth. However, the mathematical techniques applied to the study of a wide variety of mandibles, including those of a group of recent African ones, show that it is more in line with the most archaic specimens from Europe, including those from Dmanisi in Georgia.

“We find here an archaic mandible, and dental pieces which taxonomically are indisputably Neanderthal, which helps to support the hypothesis that the Neanderthal lineage did not evolve linearly but in mosaic,” explained Dr José-María Bermúdez de Castro, who led the team, together with French researcher Dr Amélie Vialet from the natural history museum in Paris.

Considered for two decades to be the oldest human fossil found in France, the mandible was described in detail by G. Billy and Henri V. Vallois in 1977. That work was undertaken more than 40 years ago, in the context of what was then known and of the theories then current on the colonisation of the European continent. However, human evolution in Europe was undoubtedly more complex than was thought only several decades ago. The possibility that there could have coexisted at least two hominin lineages and that interbreeding, prolonged periods of isolation, genetic drift and other processes were habitual in the Middle Pleistocene in Europe is gaining momentum.

“The appearance of the classic Neanderthals in the Late Pleistocene is a question by no means finally settled. There remain many open questions, and the Montmaurin-La Niche mandible now joins the list of X-files,” concluded Bermúdez de Castro.

The study, titled “A reassessment of the Montmaurin-La Niche mandible (Haute Garonne, France) in the context of European Pleistocene human evolution”, was published in the PLOS ONE journal on 16 January 2018.