An ancient skull recovered from a cave in the Annamite Mountains in northern Laos is the oldest modern human fossil found in Southeast Asia, researchers report. The discovery pushes back the clock on modern human migration through the region by as much as 20,000 years and indicates that ancient wanderers out of Africa left the coast and inhabited diverse habitats much earlier than previously appreciated. The team described its finding in a paper in Proceedings of the National Academy of Sciences. The scientists, who found the skull in 2009, were likely the first to dig for ancient bones in Laos since the early 1900s, when a team found skulls and skeletons of several modern humans in another cave in the Annamite Mountains. Those fossils were about 16,000 years old, much younger than the newly found skull, which dates to between 46,000 and 63,000 years old.

"It's a particularly old modern human fossil and it's also a particularly old modern human for that region," said University of Illinois anthropologist（人类学家） Laura Shackelford, who led the study with anthropologist Fabrice Demeter, of the National Museum of Natural History in Paris. "There are other modern human fossils in China or in Island Southeast Asia that may be around the same age but they either are not well dated or they do not show definitively modern human features. This skull is very well dated and shows very conclusive modern human features," she said.

No other artifacts（史前古器物） have yet been found with the skull, suggesting that the cave was not a dwelling or burial site, Shackelford said. It is more likely that the person died outside and the body washed into the cave sometime later, she said.

The find reveals that early modern human migrants did not simply follow the coast and go south to the islands of Southeast Asia and Australia, as some researchers have suggested, but that they also traveled north into very different types of terrain, Shackelford said.

"This find supports an 'Out-of-Africa' theory of modern human origins rather than a multi-regionalism model," she said. "Given its age, fossils in this vicinity could be direct ancestors of the first migrants to Australia. But it is also likely that mainland Southeast Asia was a crossroads leading to multiple migratory paths."

The discovery also bolsters（支持） genetic studies that indicate that modern humans occupied that part of the world at least 60,000 years ago, she said.