But the reconstructed Apidima 1, the team found, has features consistent with Homo sapiens.
"The two skulls were found in a breccia, just 30 cm apart".
Both skulls are incomplete (Apidima 1 consists of only the back of the skull, while Apidima 2 has more intact facial features), and it took anthropologists many years to extricate the fragmented fossils from the surrounding rock.
"It shows that the early dispersal of Homo sapiens out of Africa not only occurred earlier, before 200,000 years ago, but also reached further geographically, all the way to Europe", Katerina Harvati, a palaeoanthropologist at the Eberhard Karls University of Tuebingen, Germany, told AFP.
The findings support the hypothesis that early Homo sapiens spread out of Africa multiple times. But then again, humans arriving in Mediterranean Europe thousands of years later, would have eventually replaced those Neanderthals that went extinct some 40,000 years back.
Astonishingly, the fossil beats the previous Homo sapiens record by more than 150,000 years - a jawbone found in a cave in Romania.
But the skull discovery in Greece suggests that Homo sapiens undertook the migration from Africa to southern Europe on "more than one occasion", according to Eric Delson, a professor of anthropology at City University of NY. It had a thick, rounded brow ridge, and other minor characteristics of this related species. The rounded back is just like a modern human's; Neanderthals have a bulge at the back of the skull that nearly resembles a hair bun.
Apidima 1 was in pieces, and Apidima 2, the most complete skull belonging to the Neanderthal, was distorted.
"Rather than a single exit of hominins from Africa to populate Eurasia, there must have been several dispersals, some of which did not result in permanent occupations", said Delson, who was not involved in the Nature study.
But these earliest Homo sapiens voyagers died out while local Neanderthal populations persisted, she said. The digital recreation of the whole of the Apidima 1 skull to what it would have looked like led to the reclassification of the skull as a modern human (homo sapien) dating back to 210,000 years ago.
The sensational discovery provides to proof of an earlier migration of people from Africa that left no price within the DNA of people alive this present day.
It shows our species began leaving Africa much earlier than previously thought, researchers reported Wednesday.
It was only after such attempts that a human exodus from Africa, approximately 70,000 years ago, resulted in our species spreading across the globe.
If the claim is verified - and many scientists want more proof - the finding will rewrite a key chapter of the human story, with the skull becoming the oldest known Homo sapiens fossil in Europe by more than 160,000 years.
But Neanderthals also had to make way. Warren Sharp at the Berkeley Geochronology Center in California said the team's tests on the supposedly modern human skull had produced wildly different dates, a sign that uranium may have been lost from the bones over time. Experts contacted by the Guardian doubted whether the skull really belonged to a modern human, and had concerns about the dating procedure. That said, recent fossil finds in Israel suggest that modern humans had made it into West Asia as long as 177,000 years ago.