The oldest fossils of our species just got older – Popular Science

Fossils once mistaken for the 40,000-year-old remains of our Neanderthal cousins have just been thrust into the scientific spotlight. According to new research published in Nature, the Moroccan bones actually belong to our own species—and they’ve been around much, much longer than a paltry 40,000 years. With an estimated age of 315,000 years, the skeletal remains now represent the oldest known example of Homo sapiens. That’s over 100,000 years farther back in time than the species’ previous record holder.

100,000 years is an awfully long time for a species’ origin date to be pushed back. But the results just serve to confirm suspicions that many anthropologists have held for some time now. For a long time, most scientists believed that Homo sapiens evolved around 200,000 years ago, migrating out of East Africa to spread across the globe some 150,000 years later. But recent genetic evidence has suggested that our exit from the so-called cradle of humanity didn’t exactly happen en masse, and that our species may have come into its own much earlier than previously assumed.

Had the fossils studied in the new paper—found at an archaeological site known as Jebel Irhoud several decades ago—actually been 40,000 years old, they would represent a gaggle of humans who stayed put as their brethren set out into the world. But their ancient nature (confirmed using several methods, including the dating of stone tools found nearby that were reported on in a second Nature study) suggests instead that early humans spread out around Africa long before our species ventured off the continent.

“Until now, the common wisdom was that our species emerged probably rather quickly somewhere in a ‘Garden of Eden’ that was located most likely in sub-Saharan Africa,” study author Jean-Jacques Hublin of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany told Nature Magazine. Now, “I would say the Garden of Eden in Africa is probably Africa—and it’s a big, big garden.”

That lines up with recent genetic evidence that suggests human groups split into different lineages long before our shared ancestors ventured away from the continent. That implied migration could also help explain the presence of 300,000-year-old tools like spear tips found all across Africa. They represent a shift from the large axes made by earlier human relatives, and scientists weren’t sure what had led to the shift in technology. But if our ancestors were already spreading out across Africa 300,000 years ago, the presence of the relatively advanced tools makes a lot more sense.

“We had a disjuncture,” study author Shannon McPherron, also from Max Planck, told The Atlantic. “We had a major transition in behavior but no biological transition to go with it. Jebel Irhoud fills that gap nicely.”