New U-series dates on the Petralona cranium, a key fossil in European human evolution

Abstract

Assigning an age to the nearly complete cranium found in the Petralona Cave in Greece is of outstanding importance because this fossil has a key position in European human evolution. This topic has been debated since its discovery more than 60 years ago, highlighting the difficulties in applying physical dating methods to prehistoric samples. Previous results obtained on various types of samples yielded a large age range between about 170 and 700 ka, precluding any consensus on the age of the human fossil. On the other hand, the original stratigraphic position of the cranium also remains enigmatic, in spite of all the efforts provided by various researchers. Here, we present new U-series dates performed on the calcite that grew directly on the cranium, which is the only sample able to provide crucial information on the age of the fossil. The results yield a finite age suggesting that the Petralona cranium has a minimum age of 286 ± 9 ka. Other speleothems and calcitic coatings were sampled in three main locations in the cave; among them, samples came from the ‘Mausoleum’ where the cranium was supposedly found cemented to a wall. The data show that the calcite covering the cranium is not contemporaneous with that of the Mausoleum wall, despite what was previously thought. The different possibilities, depending on whether or not the cranium was attached to the wall, are discussed in the paper. From a morphological point of view, the Petralona hominin forms part of a distinct and more primitive group than Homo sapiens and Neanderthals, and the new age estimate provides further support for the coexistence of this population alongside the evolving Neanderthal lineage in the later Middle Pleistocene of Europe.