With the discovery in southern China of human teeth dating back at least 80,000 years, the history of human migration is set to be rewritten. This is because the discovery sets back by 20,000 years, the date when humans are believed to have migrated from Africa to settle in different parts of the world.

The 47 teeth were found in Limestone caves that exist across Daoxian County in Hunan Province, China.

"The fossils reveal that 80,000 years ago, the first modern humans appeared somewhere in southern China. We believe that southern China probably was a central area for modern evolution," Liu Wu, China's Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) and one of the study's lead researchers, told CNN.

"What does this mean? What is the origin of this population (of people in China)? And what is their fate? Some people really now have to reconsider models. Maybe there's not only one (migration) out of Africa, (maybe) there are several out of Africa. And also we have to understand what happened in Asia. These populations, did they really evolve also for a while outside Africa?" were some of the questions presented by this discovery of teeth, said Maria Martinón-Torres, a researcher at University College London and one of the co-leaders of the study.

There is also a surprising defect in the teeth. They have cavities, an anomaly not seen in human teeth older than 50,000 years. "It could be that early modern humans had a peculiar diet in tropical Asia. But I am pretty sure that this observation will raise some eyebrows," palaeo-anthropologist Jean-Jacques Hublin from the Max Planck Institute in Germany told The Examiner.

The study has brought forth many challenges, including dating the teeth, as none of them contained any radioactive carbon. The team had to resort to dating calcite deposits in the cave along with animal remains to come to the conclusion that the human teeth were probably between 80,000 and 120,000 years old.

"This is stunning, it's major league," said Michael Petraglia, an archaeologist from the University of Oxford in the U.K., who was not involved in the study. "It's one of the most important finds coming out of Asia in the last decade."

The study was published in the Oct. 14 issue of the journal Nature.