News from the wires: Modern humans reached westernmost Europe 5,000 years earlier than previously known

This is the first in what I hope will be a regular series highlighting new history and archaeology research from around the world, the common denominator being that I find them particularly interesting!

New research provides definitive evidence that modern humans were on the Atlantic coast of modern-day Portugal at a time when, if present at all, Neanderthal populations would have been extremely sparse. The discovery has important ramifications for our understanding of the process of modern human dispersal and replacement of Neanderthal populations. The results support a very rapid, unimpeded dispersal of modern humans across western Eurasia and support the notion that climate and environmental change played a significant role in the process.

According to the findings, modern humans probably arrived in the westernmost part of Europe 41,000 - 38,000 years ago, about 5,000 years earlier than previously known. An international team of researchers revealed the discovery of stone tools used by modern humans dated to the earlier time period in a report published in Proceedings of the National Academy of Sciences.

The tools, discovered in a cave named Lapa do Picareiro, located near the Atlantic coast of modern-day central Portugal, link the site with similar finds from across Eurasia to the Russian plain. The discovery supports a rapid westward dispersal of modern humans across Eurasia within a few thousand years of their first appearance in south-eastern Europe. The tools document the presence of modern humans in westernmost Europe at a time when Neanderthals previously were thought to be present in the region. The finding has important ramifications for understanding the possible interaction between the two human groups and the ultimate disappearance of the Neanderthals.

Tools discovered in Lapa do Picareiro in central Portugal. Image: Jonathan Haws/UofL

"The question whether the last surviving Neanderthals in Europe have been replaced or assimilated by incoming modern humans is a long-standing, unsolved issue in paleoanthropology," said Lukas Friedl, an anthropologist at the University of West Bohemia in Pilsen, Czech Republic, and project co-leader. "The early dates for Aurignacian stone tools at Picareiro likely rule out the possibility that modern humans arrived into the land long devoid of Neanderthals, and that by itself is exciting."

Until now, the oldest evidence for modern humans south of the Ebro River in Spain came from Bajondillo, a cave site on the southern coast. The discovery of stone stools characterised as Aurignacian, technology associated with early modern humans in Europe, in a secure stratigraphic context at Picareiro provide definitive evidence of early modern human arrival.

"Bajondillo offered tantalising but controversial evidence that modern humans were in the area earlier than we thought," said Jonathan Haws, professor and chair of the Department of Anthropology at the University of Louisville. "The evidence in our report definitely supports the Bajondillo implications for an early modern human arrival, but it's still not clear how they got here. People likely migrated along east-west flowing rivers in the interior, but a coastal route is still possible."

"The spread of anatomically modern humans across Europe many thousands of years ago is central to our understanding of where we came from as a now-global species," said John Yellen, program director for archaeology and archaeometry at the National Science Foundation, which supported the work. "This discovery offers significant new evidence that will help shape future research investigating when and where anatomically modern humans arrived in Europe and what interactions they may have had with Neanderthals."

Sahra Talamo of the University of Bologna, Italy, and the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, joined the research team to determine the age of the early modern human and Neanderthal occupations. She used state-of-the-art bone pre-treatment and accelerator mass spectrometry  to date the bones that show evidence of butchery cut marks and intentional breakage by humans to extract bone marrow, a highly prized and nutritious food consumed by ancient people. The dating results place the modern human arrival to the interval between 41,000 and 38,000 years ago. The last Neanderthal occupation at the site took place between 45,000 and 42,000 years ago.

"The radiocarbon results from Lapa do Picareiro are not only very precise in terms of the dating method, but also demonstrate the meticulous work of the archaeologists at the site," Talamo said. "The importance of collaboration between the radiocarbon specialist and the archaeologists is essential in order to obtain an accurate chronology like in the case of Picareiro."

Spatial analysis of high-resolution three-dimensional data confirmed the precise stratigraphic relationships between artefacts and radiocarbon samples and revealed discrete layers of occupation at the site.

"Analysis of high-resolution spatial data is crucial for documenting and observing lenses of human occupation and reconstructing occupational patterns, especially in cave environments where complex formation processes exist," said Grace Ellis, a PhD student at Colorado State University studying landscape archaeology and ancient settlement patterns.

This was backed up by artefact refitting that showed the stone tools were not moved through post-depositional processes.

While the dates suggest that modern humans arrived after Neanderthals disappeared, a nearby cave, Oliveira, has evidence for Neanderthals' survival until 37,000 years ago. The two groups may have overlapped for several thousand years in the area.

The cave sediments also contain a well-preserved paleoclimatic record that helps reconstruct environmental conditions at the time of the last Neanderthals and arrival of modern humans.

Changes in the size of limestone clasts and the chemistry of muddy fine sediment filling the cave were studied to understand the paleoclimatic context for the transition, with analysis showing that the arrival of modern humans corresponded with, or slightly predated, a bitterly cold and extremely dry phase. 

The cave itself has an enormous amount of sediment remaining for future work and the excavation still hasn't reached the bottom.

We await further exciting findings!