Nearly 42,000 years ago, ancient humans began wielding a new kind of Stone Age toolkit in southern Europe—one that included perforated shell ornaments and long, pointed stone bladelets that were thrown long distances atop spears. Now, after decades of speculation about who made the tools, scientists have finally shown that they were crafted by modern humans, rather than Neandertals. The technological breakthrough may have helped our species outcompete Neandertals, who went extinct shortly after the new tools appeared in Europe.

The proof comes from a new state-of-the-art analysis of two baby teeth found in 1976 and 1992 at separate archaeological sites in northern Italy. At the time, researchers were unable to tell whether they belonged to modern humans or Neandertals. But in the new study, an international team of researchers led by Stefano Benazzi of the University of Bologna in Italy used three-dimensional digital imaging methods, including computerized tomography scans, to measure the thickness of the enamel of one of the teeth, found at the collapsed rock shelter of Riparo Bombrini in the western Ligurian Alps. The enamel was thick, as in modern humans, rather than relatively thin, as in Neandertals, the authors report online today in Science. And new radiocarbon dates on animal bones and charcoal from the site suggest this modern child lived there approximately 40,710 to 35,640 years ago.

The researchers were also able to extract maternally inherited mitochondrial DNA (mtDNA) from the other child’s tooth from Grotta di Fumane, a cave in the western Lessini mountains, which dated between 41,110 and 38,500 years ago. When researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, sequenced the mtDNA and compared it with that of 10 ancient modern humans and 10 Neandertals, they found it belonged to a known lineage of mtDNA, called haplogroup R, which has also been found in a 45,000-year-old modern human bone found in a riverbank near Ust’-Ishim, Siberia.

This identification of the remains is “the long waited confirmation” that modern humans made these advanced tools, known as Proto-Aurignacian tools, says archaeologist Nicolas Zwyns of the University of California, Davis, who was not involved in the study. These tools eventually transformed into the so-called Aurignacian version, characterized by bone and antler tools, ornaments, and figurative art, he notes.

The convergence of the new dates with the DNA and fossil evidence also shows that there is now “a period of overlap of at least 3000 years between Neandertals and modern humans,” says Jean-Jacques Hublin, a paleoanthropologist at Max Planck and senior author of the paper. And although it wasn’t as if “Neandertals were on one side of the valley and moderns were on the other, waving their hands at each other every morning,” he says, the entry of modern humans into Europe may have played a part in Neandertal extinction. Although other factors, such as disease and less sophisticated social and trade networks may have also contributed to their demise, says archaeologist Ofer Bar-Yosef of Harvard University, who was not involved with the study, “it is quite possible that this efficient hunting technology gave a competitive edge to modern humans over the Neandertals.”