Our species, born in Africa, trekked to the limits of Western Europe by at least 41,000 years ago—and so shared the continent with Neandertals for thousands of years, according to two new studies published online today in Nature. A new look at two infant teeth from Italy and new dates for a jawbone and teeth from Kents Cavern on the south Devon coast of England conclude that they belonged to our species rather than to Neandertals, as once thought. The Italian teeth date to 43,000 to 45,000 years ago, making them the teeth of the oldest known modern humans in Europe.
Researchers had suspected that our ancestors had invaded Europe from Africa by 42,000 years ago because they had found distinct and complex tools as early as that date, such as the first carefully shaped bone, antler, and ivory tools; a sudden proliferation of perforated animal teeth, carved marine shells, stone and ivory beads, and other forms of ornaments thought to be crafted only by Homo sapiens.
But the oldest fossils of H. sapiens on the continent were dated to only about 40,000 years ago, with wide margins of error, at Oase, Romania. No other modern human remains appear in Europe until about 37,000 years ago. So researchers have argued about how long moderns overlapped with Neandertals, who disappeared by 30,000 years ago. They also debated which species made so-called transitional industries—tools and jewelry that are more sophisticated than the typical Neandertal output but not as advanced as the tools made by moderns.
If the Italian infant teeth are those of modern humans, then one important "transitional" industry, the Uluzzian, was likely the handiwork of H. sapiens, not Neandertals. The work makes it "much less likely that Neandertals developed their own Upper Paleolithic suite of behaviors before the arrival of anatomically modern humans," according to a report by paleoanthropologist Stefano Benazzi of the University of Vienna and colleagues.
Researchers used a refined carbon-dating technique called ultrafiltration to redate animal bones associated with the British jawbone to 41,000 to 45,000 years old, making it the oldest modern human in northwest Europe. A separate technique dated shell beads associated with the infant teeth in Italy, putting moderns on both ends of the continent earlier than expected—and at the same time as Neandertals were there.
"Modern humans got a lot further faster than we thought," says co-author Chris Stringer of the Natural History Museum in London. So Neandertals and modern humans had at least "3000 to 5000 years of overlap" in central Europe, possibly longer in southern and Eastern Europe, says University of Oxford geochronologist Thomas Higham, who dated the British site. That gives the two groups plenty of time to interact, whether by trading technology, fighting, or mating.
Others acknowledge the new dates but insist that ornamental shells and body painting associated with Neandertal remains in Spain suggest that it's "unwarranted" to say that Neandertals did not make transitional technologies. "These Spanish finds make it clear that symbolic behavior existed among the Neandertals before the time of the transitional industries," archaeologist João Zilhão of the University of Barcelona says.