Not Enough Evidence to Back Claim that Humans Originated in Europe

Africa is not the cradle of humankind: that’s the claim by a group of scientists who’ve just published what they describe as evidence of pre-human remains found in Eastern Europe (Greece and Bulgaria). The fossils in question belong to Graecopithecus freybergi, and are a little more than seven million years old. This would make them the world’s oldest hominin fossils.

It would also re-root the human evolutionary tree in Eastern Europe, away from Africa. This runs counter to a great deal of evidence which suggests that humans originated in Africa.

Dr Julien Benoit, a vertebrate palaeontologist and palaeobiologist who has worked extensively on the African continent and was not part of the European research team, chatted to The Conversation Africa about the findings.

This new research suggests that Greece, not Africa, should be calling itself the cradle of humankind. Do you think that’s accurate?

Extraordinary claims need extraordinary evidence to support them. The African origin of humankind (Hominini) is currently supported by two really important elements.

Firstly, thousands of hominin fossils have been found on African soil since the first fossil African hominin, Australopithecus africanus, was discovered in South Africa in 1924.

Nearly a century of fossil findings has followed, chronicling the complete evolution of hominin on African soil. These fossils range from the Sahelanthropus, which lived between six and seven million years ago in what is today Chad, to the earliest Homo sapiens from east Africa.

Secondly, our closest ape relatives, the Chimpanzees and the Gorilla are also from Africa. Our last common ancestors lived somewhere between eight and 12 million years ago, which strongly suggests that the origin of humankind is deeply rooted in Africa. This leave little room for a putative European origin.

Any study that counters this consensus would have to provide very strong evidence and perfect methodology to support its claim. In my opinion, this article doesn’t meet those criteria.

Why not?

For starters, the material isn’t well preserved. It consists mostly of a jaw with no complete teeth preserved. That’s a problem because the teeth’s anatomical characteristics are the most important element when classifying any primate, including humans.

The authors claim that the jaw’s fourth premolar root is similar to that of a hominin’s. This is not a character that is conventionally used in palaeoanthropology, especially because not all hominins have similar tooth roots. This character is rather variable – and the authors go on to acknowledge this – so it’s unreliable for classification.

They also argue that the small size of the incomplete canine tooth (as suggested by the size of its root) would put this fossil close to hominin ancestry. This is based on the assumption that hominins are the only apes with small canines. This, again, is not true. In Europe, where apes have a very rich fossil record, there’s an ape called Oreopithecus which has small canines but is not related to humans at all.

This is an example of independent, parallel evolution: when one species evolves similarities to another without being related to it. For instance, dolphins look like fish, but they’re not. This is probably the same thing for Graecopithecus and hominins.

I agree with many of my colleagues, who think that this new jaw represents an Ape species that is not related to humans. It might belong to a species like Oreopithecus, which evolved human-like features – such as the fusion of the fourth premolar roots and small canines – in parallel to our lineage.

Finally, the study is lacking a phylogenetic analysis. This is a statistical method used to reconstruct a reliable evolutionary tree. To say that a fossil species is an early hominin without performing this kind of analysis is like giving the result of an equation without actually doing the maths.

What sort of further research and clarification is needed to confirm or debunk this theory of European origins?

A phylogenetic analysis is crucial. This is a way to reconstruct the evolutionary tree of species and to address the hypotheses of any relationship between them.

It will allow scientists to assess this fossil jaw’s real position in the evolutionary tree of Primates and to actually test if the similarities observed between Graecopithecus and hominins were acquired independently or were inherited from a real common ancestor.

And if their claim turns out to be true, would that mean we need to totally rewrite history?

The theory that humankind originated in Europe is an old one. It was abandoned after 1924 when the first Australopithecus was discovered in South Africa.

Since then, thousands of fossils have been found around Africa that strongly support the “African origins” hypothesis. Even if this new fossil actually turns out to be a hominin, it would only be an outlier – like a drop in the ocean. It would change very few things, because much more and far better preserved material would be necessary to totally disprove the African origin of humankind.

It would open a brand new area of research, but would not change textbooks.

Julien Benoit, Postdoc in Vertebrate Palaeontology, University of the Witwatersrand

This article was originally published on The Conversation. Read the original article.