Scientists say they've identified the earliest sign of our species outside Africa, with a chunk of skull recovered from a cave in southern Greece.
Its estimated age is at least 210,000 years old, making it 16,000 or more years older than an upper jaw bone from Israel that was reported last year.
It shows Homo Sapiens began leaving Africa much earlier than previously thought, researchers reported Wednesday.
Other research has concluded that the exodus from Africa didn't happen until more than 100,000 years later.
The fossil, from the rear of a skull, was actually found decades ago - excavated in the late 1970s from the Apidima Cave in the southern Peloponnese region of Greece and later kept in a University of Athens museum.
"Not a lot of attention was paid to it," said Katerina Harvati of the University of Tuebingen in Germany, who was invited to study the fossil.
Harvati and others report the results of their analysis in the journal Nature. To establish the age, they analysed bits of bone from the fossil. To identify what species it came from, the researchers compared a virtual reconstruction to the shapes of fossils from known species.
But some other scientists are not convinced the fossil's reported age and identification are correct.
Warren Sharp, an expert on dating fossils at the Berkeley Geochronology Centre in California, said the age of 210,000 years is "not well supported by the data."
Ian Tattersall of the American Museum of Natural History in New York called the case for identifying the fossil as H. sapiens "pretty shaky." Its shape is suggestive, but it's incomplete and it lacks features that would make the identification firmer, he said in an email.
In response, Harvati said the back of the skull is very useful for differentiating H. sapiens from Neanderthals and other related species, and that several lines of evidence support the identification.
