Forty-seven human teeth, discovered in a cave in China, are forcing scientists to question our understanding of when and how our ancestors left Africa to migrate across the world. The teeth, which “unequivocally” belong to Homo sapiens, are more than 80,000 years old, suggesting that our species arrived in Asia much earlier than previously believed.

“This is stunning, it’s major league,” Michael Petraglia, an archeologist at the University of Oxford, U.K., who was not involved in the research that led to the discovery and eventual dating of the teeth, told Nature. “It’s one of the most important finds coming out of Asia in the last decade.”

Current theories suggest that our species -- the Homo sapiens -- evolved in Africa approximately 200,000 years ago. Prior to the latest discovery, which was made in a cave in Daoxian in southern China, scientific evidence suggested that our ancestors began colonizing the world only around 60,000 years ago. Older traces of modern humans previously discovered outside Africa, such as the roughly 100,000-year-old remains from the Skhul and Qafzeh caves in Israel, were discarded by scientists as evidence of unsuccessful efforts at wider migration.

The teeth challenge this theory, raising doubts over the timing of the first migration out of Africa. The findings may also mean that our ancestors arrived in Asia and Europe in multiple waves.

“This is a rock-solid case for having early humans -- definitely Homo sapiens -- at an early date in eastern Asia,” Chris Stringer, a paleoanthropologist at the Natural History Museum in London, who was not part of the research, told Nature.

Additionally, the findings also raise questions over why modern humans seemed to have reached Asia much before their migration to Europe, where the earliest such remains found are approximately 45,000 years old. A possibility is that Homo sapiens faced stiff competition over resources from the Neanderthals who had already populated parts of Europe, and they could only enter the continent when the Neanderthals were at the brink of extinction.

“This is just the tip of the iceberg,” Petraglia told Nature. “There’s a lot more work that needs to be done.”