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Older than Dirt

Re-analysis shows jawbone to be from earliest modern human in Europe.

New dating of a piece of jawbone excavated from a cave in England 85 years ago shows it is the earliest evidence for modern humans in Europe, according to an international team of scientists.

Beth Shapiro, the Shaffer Associate Professor of Biology at Penn State and a member of the research team, explained that the fragment of maxilla—the upper jaw—containing three teeth was unearthed in 1927 in a prehistoric limestone cave called Kent’s Cavern in southwestern England. ”In 1989, scientists at Oxford University dated the bone as being about 35,000 years old. However, doubts were later raised about the reliability of the date because traces of modern glue, which was used to conserve the bone after discovery, were found on the surface,“ Shapiro says.

Because the remaining uncontaminated area of bone was deemed too small to re-date, Shapiro and her colleagues searched through the excavation archives and collections in the Torquay Museum in Devon, England, where the maxilla has long been housed, to obtain samples of other animal bones from recorded depths both above and below the spot where the maxilla was found. Radiocarbon dating of these bones—of wolf, deer, cave bear, and woolly rhinoceros—showed them all to be between 50,000 and 26,000 years old. Using statistical modeling to combine the relative stratigraphic data with the radiocarbon findings, the researchers were then able to calculate a new age for the maxilla at between 41,000 and 44,000 years old. Tom Higham, deputy director of Oxford University’s Radiocarbon Accelerator Unit and a member of the research team, says, "The new dating evidence we have obtained allows us, for the first time, to pinpoint the real age of this key specimen. We believe this piece of jawbone is the earliest direct evidence we have of modern humans in northwestern Europe."

It also helps confirm the much-debated theory that early modern humans coexisted with Neanderthals, Shapiro says. “If the jawbone is, in fact, 41,000 to 44,000 years old, that means it was from a time when Neanderthals were still present in Europe, so we first had to confirm that the bone was from an anatomically modern human, and not a Neanderthal,” she says.

Although attempts to extract mitochondrial DNA for sequencing were unsuccessful, team members were able to use a virtual three-dimensional model based on a CT scan of the jawbone to carry out a detailed analysis of the fossil. They compared the external and internal shapes of the teeth with those of modern human and Neanderthal fossils from a number of different sites and found early modern human characteristics in all but three of 16 dental characteristics.

The new study could also help solve the apparent discrepancy about the known dates of the Aurignacian period—a time of cultural development in Europe and southwest Asia that lasted from around 45,000 to 35,000 years ago. Previous researchers have discovered artifacts and tools from this period that are thought to have been produced by the earliest modern humans in Europe. However, these artifacts have been found to be much older than the rare skeletal remains found in the same vicinity. “The new date and identification of this bone from Kent’s Cavern is very important, as we now have direct evidence that modern humans were in northwest Europe about 42,500 years ago,” Higham says. “It confirms the presence of modern humans at the time of the earliest Aurignacian culture, and tells us a great deal about the dispersal speed of our species across Europe during the last Ice Age.”

Beth Shapiro, Ph.D., is Shaffer Career Development Professor of Biology in the Eberly College of Science, beth.shapiro@psu.edu.

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Original publication date November 16, 2011.
Most recently updated November 16, 2011.