Could Fossil Ape Found in Turkey Upset the Story of Human Evolution?

Analysis of Anadoluvius turkae increases diversity of large apes in Mediterranean region, a few million years earlier than in Africa, archaeologists say – but the case of our distant origin isn’t closed

Our species emerged in Africa. This is not debated. How long ago Homo sapiens emerged and what it did after emerging is heatedly debated. But an even deeper mystery is where the story of the entire “hominine” line – which encompasses all African apes and hominins – began.

Put otherwise, the question is where the common ancestor to African apes and the Homo line emerged, and the classic answer is Africa. But there is also a case for a Eurasian origin – and it may have grown stronger with the discovery of a previously unknown type of 8.7-million-year-old hominine in Çorakyerler, Turkey. It has been called Anadoluvius turkae and analysis of this previously unknown creature appeared recently in the Nature journal Communications Biology.

A moment on terminology: “Hominine” broadly encompasses African apes and humans, while “hominin” narrowly refers to the line of humans plus our extinct relatives, without the apes. Gorillas are hominines but not hominins. Ignore the orangutans, whose lineage split off from other apes many millions of years before the split between African apes and the Homo line.

Based on their analysis of Anadoluvius’ skull and its classification as a previously unknown ancient European hominine – and adding it to the growing list of ancient hominines discovered in the Mediterranean region – Ayla Sevim-Erol of Ankara University, David Begun of the University of Toronto and colleagues argue the case of the hominine line emerging in Eurasia and subsequently expanding to Africa. In Europe these lineages died out, but in Africa they experienced rapid diversification, resulting in the great apes we know and love (and are driving to extinction), and the various hominins, which includes us.

The African origin was assumed based on that being where the earliest agreed-on members of the line culminating in humans had been found. Also, Africa is also home to multiple great apes and there are none in Europe. But in recent years, fossils from ancient hominines have been found in Bulgaria, Turkey and Greece that predate the earliest known African fossil hominin, Sahelanthropus tchadensis, which lived about 7 to 6 million years ago. This has thrown a monkey wrench into the works.

Scholars have reported quite the collection of European/Mediterranean hominines from the late Miocene (which began 10.4 million years ago): Ouranopithecus macedoniensi, Ouranopithecus turkae, Ankarapithecus meteai, Graecopithecus freybergi – and now Anadoluvius.

True, scholars will squabble over the ages and classifications of these beings. Asked how many hominines were running around the Mediterranean about 10 million years ago, Begun sums up by email: “We know of three between about 9.5 and 7.2 million years ago. One sample from the site of Nikiti in northern Greece might be another taxon. At this point, given the small sample (two jaws) and damage to the specimens, it is not clear if the Nikiti hominines are Ouranopithecus or Anadoluvius or something else.”

So the earliest known hominines are European, not African? Are there no signs of hominines in Africa before the contentious wee-brained Sahelanthropus – which some say was the “earliest member of the human line” and others think wasn’t in that line at all but was an ape pure and simple, even if a bipedal one? The truth is out there, we just aren’t sure what it is.

The diversified ape

The Late Miocene site of Çorakyerler is near the city of Çankırı in central Turkey, about 140 kilometers (87 miles) north of Ankara. It has also been a rich source of fossils from megafauna, some of which Anadoluvius presumably hunted and ate, including rhinos and early horses that for some reason reconstructions show looking like zebras. But to our point, the authors of the new paper argue that the discovery of Anadoluvius supports the theory that hominines had emerged and diversified in Europe well before their appearance in Africa, in the form of Sahelanthropus.

“The evidence leads us to conclude at this time that the oldest hominines are European,” Begun says. “Sahelanthropus [in Africa] is about 7 million years old, while Anadoluvius and Ouranopithecus [in Europe] – which are widely regarded as hominines – are between 9.5 and 7.2 million years old.

“If we are right that older fossils from Europe such as Dryopithecus and Rudapithecus are also hominines, which is admittedly more controversial, that would be European hominines at more than 12 million years ago,” he adds.

Prof. Israel Hershkovitz of Tel Aviv University, an expert on human evolution who was not involved in this study, says there are some inconclusive indications of earlier hominines in Africa: some long bones and jaws. But it is also possible that Graecopithecus and now Anadoluvius are variants in the same group. That dubiety does not detract from the momentous discovery of Anadoluvius: the facial bones and skull found at Çorakyerler provide new information on the hominines in Europe from about 10 to 7 million years ago, Hershkovitz applauds. But the arguments in both directions, European or African origin, remain; and so do the politics of the conundrum.

The Anadoluvius scholars strongly feel their analysis supports the theory that the common ancestors of hominines (apes + humans) arose in Eurasia, spread to Africa between 9 to 6 million years ago and began to diversify madly there – resulting in everybody from gorilla to politicians. They also say that Anadoluvius doesn’t prove the thesis, though “the diversity of hominines in Eurasia suggests an in situ origin but does not exclude a dispersal hypothesis,” they sum up.

Evidence of a crime

According to the team, Anadoluvius differs from its contemporaries Graeopithecus and Ouranopithecus in the face, the palate, neurocranium, mandible, dental root and root canal configuration.

“There are always people who prefer to put all fossils that resemble each other in a single taxon (lumpers). This is a philosophy that I would describe as outdated,” Begun says. “There was a time when all fossil apes were lumped into the genus Dryopithecus, spanning a time range from 20 to 9 million years ago. Today, at least two dozen taxa within this group are recognized by virtually all researchers.”

Ouranopithecus, Graecopithecus and Anadoluvius all belong to the same subfamily, the hominines, but no scholars who actually studied their fossils say they belong to a single genus, Begun says. It is true that the differences between them are “a bit technical,” which also applies to the differences between the nearly universally accepted separate genera Ardipithecus, Australopithecus, Paranthropus and Homo in Africa, he explains. “The differences are beyond what we would expect in a single species, judging from the variations that we see in living apes,” he says.

He adds that their analysis of Anadoluvius confirms previous interpretations that Ouranopithecus was one of ours. “The new specimens cover anatomy not known for Ouranopithecus,” he explains. “When it was added to the program we used to calculate the most parsimonious evolutionary relationships, it confirmed that Ouranopithecus is also a hominine, as are the older European Dryopithecines.”

Could there have been hominines in Africa at the same time, before Sahelanthropus, but “convincing” remains haven’t been found?

“If you have evidence of an event – say a person having committed a crime – would you dismiss it because you think there might be evidence that someone else did the deed but you just haven’t found it yet?” Begun answers. The evidence of hominines in Europe is strong, irrespective of whether or not they existed in Africa. Also, “when you think about it, is this how science works? Do we dismiss hypotheses based on real tangible evidence because we think we might eventually find evidence of an alternative hypothesis?” he says. “The absence of evidence is special pleading that comes from a deeply seated bias that Africa must be the place of origin of the hominines.”

Prof. Ran Barkai of Tel Aviv University adds that there are primates pretty much everywhere, but so far Africa is the only place with solid evidence of the emergence of the human line. “We shall live and see,” he sums up, while agreeing that the debate is not innocent of politics.

Yet the question is less the origin of the hominins and more the origin of the hominines – the common ancestor of apes and humans. Begun argues that “it is certainly unparsimonious to suggest that while hominines were in Europe and the eastern Mediterranean, they are not ancestral to living African apes and humans but extinct side branches, since the real ancestors are in Africa but we haven’t found them yet. That is precisely the argument against the ‘out of Europe’ hypothesis.”