The world of paleoanthropology gets thoroughly shaken pretty often these days. New fossils are sometimes found, and as dating technology improves, we revisit old fossils with new dating tools. And when both happen, that often requires having to alter the story we tell ourselves about the ancestry, movement and timelines of the known human species.
Two new studies published in the journal Nature take the story we've been telling ourselves about the origins of our own species and basically wads it up, torches it, tosses it out the window and then backs over it with a car. According to the research team, the fossilized remains of a Homo sapiens (and some of their tools) found in a barite mine in Morocco called Jebel Irhoud half a century ago are not, as was recently thought, 160,000 years old. (And not, as when they were discovered in 1961, initially estimated at only about 40,000 years old.) They are, in fact, 315,000 years old. Which... well, is a big difference. And since researchers have heretofore put our species' origins at about 200,000 years ago — the oldest clearly human fossils known up to this point were discovered in Ethiopia, and date to about 160,000 and 195,000 years old — that means we're more than 100,000 years older than we thought.
And based on the fact that these ancient human bones were found in Morocco — nowhere near the "Garden of Eden" in East Africa where we've long assumed modern humans evolved, and from which they dispersed — it also means that our origins are probably much more complicated than we assumed, geographically speaking.
"Our new data reveal that Homo sapiens spread across the entire African continent around 300,000 years ago," said coauthor Jean-Jacques Hublin, a palaeoanthropologist at the Max Planck Institute for Evolutionary Anthropology, in a press release. "Long before the out-of-Africa dispersal of Homo sapiens, there was dispersal within Africa."
So, what they're saying is, the Garden of Eden was probably enormous, and our evolution complicated.
In recent years the researchers discovered skull bones from five individuals, as well as blades found at the dig site dated to about 300,000 years ago. This surprising discovery led Hublin and his coauthors to re-examine the earlier Jebel Irhoud site using new dating methods because those specific Homo sapiens specimens have long puzzled researchers — they seem much more primitive than other specimens assumed to be from around the same time. The teeth of these early humans were larger, and their skulls more elongated than ours (suggesting their brains were probably organized a bit differently), but they probably appeared pretty much the same as modern Homo sapiens.
Perhaps the most exciting discovery from the re-dating of the Jebel Irhoud site is that it suggests that East Africa isn't the only place to look for clues to our early evolution, the scientists say.
"North Africa has long been neglected in the debates surrounding the origin of our species," says coauthor Abdelouahed Ben-Ncer of the of the National Institute for Archaeology and Heritage in Morocco. "The spectacular discoveries from Jebel Irhoud demonstrate the tight connections of the Maghreb with the rest of the African continent at the time of Homo sapiens' emergence."
Chris Stringer, a palaeoanthropologist at the Natural History Museum in London, who co-wrote an article to accompany the studies, said in Nature that the new finds "shift Morocco from a supposed backwater in the evolution of our species to a prominent position."
And Philipp Gunz, a paleoanthropologist and co-author of two new studies on the fossils, told the New York Times, "We did not evolve from a single 'cradle of mankind' somewhere in East Africa. We evolved on the African continent."