Humanity's messy journey just got messier. A fossil skull from southern Greece has been identified as belonging to Homo sapiens and dated as at least 210,000 years old. If both claims prove true it would demonstrate that H. sapiens left Africa more than 100,000 years before our world-conquering dispersal. For some reason, this expansion failed to create a lasting presence.
When two skulls were first found in Apidima Cave in the 1970s they attracted interest because evidence for a Pleistocene-era human presence in Greece is otherwise almost non-existent. However, each had been distorted or fragmented, and the nature of the rocks in which they were buried made them hard to both extract and date accurately.
Archaeological technology has advanced since then, and an international team has re-examined the skulls and the strata in which they were found. Using computer tomography to reconstruct the skulls they have determined that one of the skulls came from a modern human (ie Homo sapiens), while the other belonged to a Neanderthal. In Nature, the team reports that uranium series dating indicates they have respectively been buried for at least 210,000 and 170,000 years, although the rock around them was solidified more recently.
Finding a Neanderthal skull in a region they have not been found before is interesting, but it is the H. sapiens one that has really shaken things up. Although this skull is much less complete than its counterpart, it has a rounded back, one of the clearest differences between H. Sapiens and Neanderthal skulls, and lacks distinctive Neanderthal features.
Somewhere between 50,000 and 100,000 years ago, H. sapiens engaged in a great expansion out of Africa. We traveled into a world already populated by other human species, including Neanderthals, which had left Africa long before. However, we now know that this was not the first H. sapiens dispersion, with evidence from Misliya Cave showing a previous expansion at least as far as Israel 177-194,000 years ago.
Given our species' migratory ways it might have been expected these pioneers would have quickly taken over much of the world, but it didn't happen. Archaeological evidence of this previous expansion is sparse enough to suggest it didn't survive all that long. Moreover, genetic evidence links all non-Africans to a single, much more recent migration. This was followed by interbreeding with Neanderthals and Denisovans, but not with any pre-existing H. Sapiens population, as would undoubtedly have happened if they had survived.
Consequently, it seems the first inhabitants of Apidima died out and were replaced by Neanderthals, who many years later were replaced by the great dispersal.
Today the Apidima Cave can only be reached by water, but during ice ages it would have opened onto a coastal plain. The authors say their dating methods are not precise enough to know what conditions would have been like when the owner of either skull lived there.
Sadly no tools have been recovered from the cave, and the only animal fossil is a turtle carapace.
At a media conference, first author Professor Katerina Harvati of the University of Tübingen was pessimistic about the prospects of extracting DNA from the skulls, but said the team still intends to try. It may, however, be possible to collect proteins that at least confirm the species designation.