A study published Monday suggests that early human ancestors diverged from chimpanzees in Europe — not Africa, as previously believed — in a discovery that challenges the mainstream narrative of where we come from. The article by Jochen Fuss of Eberhard-Karls-University and colleagues was published in PLOS ONE.

Critics challenge that there just isn’t enough evidence to support this controversial version of events. Proponents say there isn’t enough evidence to disprove it, either.

“In this interpretation, an early member of the human lineage, Graecopithecus, lived in Europe at 7.2 million years ago, indicating that humans were not confined to Africa at this time and may in fact have evolved in Europe,” David Begun, Ph.D., an anthropologist at the University of Toronto and one of the study’s authors, tells Inverse.

Let’s be clear — even in Begun’s telling, human evolution occurred primarily in Africa. He does not dispute that Homo erectus emerged in Africa some two million years ago before fanning out across Europe and Asia, evolving into the Neanderthals, Denisovans, and other human cousins. Begun’s research has equally no bearing on the “out of Africa” theory, which supposes that the first Homo sapiens evolved in East Africa before migrating into Eurasia beginning about 100,000 years ago.

The question that Begun and colleagues grapple with is much more ancient: Where did human ancestors evolve a genetic identity separate from chimpanzees? We know that at some point, the human lineage diverged from the one that went on to evolve into chimpanzees. Where did the earliest members of that human line live? It’s not scientifically valid to assume that they must have been in Africa because their descendants were there, million of years later. And we know there was a great diversity of apes across Eurasia about seven million years ago, which roughly coincides with the time the human line would have diverged from that of chimps. Why couldn’t that common ancestor have been European, only to migrate to Africa later as the climate changed?

a, Type mandible of G. freybergi from Pyrgos, Greece. b, RIM 438/387 –Left P4 of cf. Graecopithecus sp. from Azmaka, Bulgaria.
Features in these root canals suggest a genetic relationship to humans, maybe.

Begun says he’s got mounting evidence that this is the likely version of events, and he’s waiting for the evidence that proves him wrong. Sure, it may be tidier to assume the common ancestor of chimps and humans was confined to Africa, but there’s nothing tidy about evolution and speciation over millions of years.

“Most of my colleagues will always be skeptical of a European origin of modern great apes and humans,” he says. “If the very same evidence had been found in Africa there would be much more acceptance, which is a problem because it reveals an unscientific bias.”

His latest research examines Graecopithecus freybergi, a species known only from a badly degraded piece of jaw discovered in 1944 in southern Greece. In the study, the scientists also considered a single molar found in Bulgaria that might also have belonged to the Graecopithecus genus. They mapped for the first time the internal structure of the teeth and found two features that suggest this ape was more closely related to us than to chimpanzees — partially fused roots in the molar, and shortened roots in the canine.

Begun admits these observations are not a lot to go on, but he hasn’t seen better fossil evidence for human-line ancestors existing at that time in Africa. “I am not saying that the evidence is absolute; there is no such thing in paleontology,” he says. “But the hypothesis to be falsified has to be that Graecopithecus is a hominin.” The scientific term hominin includes humans and all human-like apes that are more closely related to us than to chimpanzees.

Begun’s skeptical colleagues have a point that it’s a bit of an overreach to conclude that Graecopithecus is a hominin from the evidence at hand. But there’s not enough evidence, either, to say it wasn’t. It’s not good scientific practice to throw away data points that challenge an assumed version of events. What’s better is to go out and look for others that tell more of the story. That’s what Begun plans to do.

“We would need better fossils of the skull and especially limb bones to demonstrate more conclusively that hominins were present in Europe at 7.2 million,” he says. “My colleagues and I hope to find such evidence in Bulgaria, where there are many sites of the right age.”

Photos via Fuss et. al / PLOS ONE, William Warby / Flickr