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A new modeling study by Leiden University and University of Cambridge scientists predicts the appearance of Homo sapiens and the Protoaurignacian culture in France and northern Spain at 42,269 to 42,653 years ago, and the 'extinction' of the Châtelperronian culture and regional Neanderthals at 39,894 to 39,798 and 40,870 to 40,457 years ago, respectively — suggesting a possible overlap of around 1,400 to 2,800 years between these human groups in the region.

Between 40,000 and 50,000 years ago, the demographic landscape of Europe is transformed as Neanderthals are replaced by anatomically modern humans and disappear from the fossil record.

Recent evidence from Bulgaria, the Czech Republic, and south-eastern France indicates that the first anatomically modern humans arrived in Europe by at least 47,000-45,000 years ago and possibly as far as 54,000 years ago.

At a continental scale, this would suggest a possible overlap of upwards of 14,000 years between these human species.

Yet, little is known about the nature, timing, and specific geographic areas of interaction between Neanderthals and Homo sapiens during this critical period in human evolutionary history.

In the new research, Leiden University scientist Igor Djakovic and his colleagues analyzed a dataset of 56 Neanderthal and modern human artifacts (28 for each group) from 17 archaeological sites across France and northern Spain, as well as an additional 10 Neanderthal specimens from the same region.

All samples had been radiocarbon dated using robust modern techniques since 2000 for greater accuracy.

The researchers used optimal linear estimation and Bayesian probability modeling to estimate the date ranges for these samples and the populations responsible, and infer the earliest and latest dates that these human groups might have been present at the sites.

This modeling served to fill in missing portions of the archaeological record, which hamper date estimation.

Based on this modeling, the authors estimate that Neanderthal artifacts first appeared between 45,343 and 44,248 years ago, and disappeared between 39,894 and 39,798 years ago.

The date of Neanderthal extinction, based on directly-dated Neanderthal remains, was between 40,870 and 40,457 years ago.

Modern humans were estimated to first appear between 42,653 and 42,269 years ago.

"Taken together, these observations strengthen the proposition that the initial Upper Paleolithic in this region likely involved a period of co-existence between Neanderthals and Homo sapiens," the scientists said.

"The precise nature of this co-existence, however, remains to be resolved."

The study was published in the journal Scientific Reports.
I. Djakovic et al. 2022. Optimal linear estimation models predict 1400-2900 years of overlap between Homo sapiens and Neandertals prior to their disappearance from France and northern Spain. Sci Rep 12, 15000; doi: 10.1038/s41598-022-19162-z