Modern humans in the Levantine corridor 55,000 years ago

But did they encounter Neanderthals?

Hershkovitz et al report the discovery report the discovery of a partial skullcap at Manot Cave, Western Galilee. The skullcap has been dated by uranium/thorium methods to 54,700 +/- 5,500 years old. Its describers note archaic features such an occipital bun but claim that it is ‘unequivocally modern’. Although the occipital bun is associated with Neanderthals, it was also common among early Upper Palaeolithic modern humans. The describers admit that taxonomic significance of Manot 1’s mosaic of archaic and modern features is unclear, but note that hominins with similar combinations are known from the fossil record of the Levant and sub-Saharan Africa until and even after 35,000 years ago. Geometric morphometric studies align Manot 1 with recent and Upper Palaeolithic modern humans, but it is more distant from some (but not all) Middle Palaeolithic modern humans.

Although modern humans were in the Levant around 115,000 years ago, it is believed that they did not remain there after 75,000 years ago following the onset of the cold, arid conditions of Marine Isotope Stage 4. By 70,000 years ago, Neanderthals had re-occupied the region: the two human species ‘time-shared’ the region as the climate alternated between warm, wet and cold, arid. It has been suggested that the Neanderthal presence persisted until 50,000 or even 45,000 years ago.

If modern humans were in the region no later than around 50,000 years ago, the implication is that the two human species might have come into contact. The authors of the Manot 1 report speculate that its’ mosaic of archaic and modern features could indicate that it is a Neanderthal/modern hybrid.

While this view is certainly feasible, it is not without problems. Many of the radiocarbon dates placing Neanderthals in the Levant at the time in question were obtained in the 1960s, and the true dates may be nearer 60,000 years ago. It is therefore possible that the two human species missed each other by several thousand years; this would be consistent with the ‘time-share’ view that their respective ranges ebbed and flowed in sequence with warm/cold climatic cycles.

On the other hand, it is certainly possible that descendants of the Manot population later migrated to Europe, where the latest radiocarbon dates suggest that modern humans associated with the Aurignacian culture arrived around 46,000 years ago.

References:

1. Hershkovitz, I. et al., Levantine cranium from Manot Cave (Israel) foreshadows the first European modern humans. Nature (2015).