About nine million years ago, during the Miocene, our evolutionary path separated from that of the chimpanzee. Since chimpanzees live in Africa, and Homo sapiens also evolved there, everyone assumed our paths diverged there as well. But a new study suggests the possibility that our last common ancestor came from Europe, and that fossil teeth may help us solve this question.

Succumbed or avoided death

One thing we know for sure: nine million years ago there were great apes in Europe. At that time, Europe was still heavily forested, forming an ideal habitat for not only great apes, but also, for example, big cats. Shortly thereafter, the European climate changed dramatically; forests disappeared and grasslands took their place. The European apes were not accustomed to this new environment and were displaced. These great apes had two options: flee to Africa, or become extinct.

We don’t know for sure what happened to these great apes. Chances are that they arrived in continental Africa via Anatolia, now known as Turkey. But this would only be possible if Anatolia was sufficiently forested. The European great apes were not suited for long-term survival on grasslands, so they would have had to move from forest to forest. We don't know for sure if this happened because very little is known about the climate and ecosystem of Anatolia from nine million years ago. The only way to know more about this is to actively look for clues. As Yanell Braumuller, PhD student and researcher at Naturalis Biodiversity Center, put it, “Where you dig the most, you'll find the most.”

To wear a crown

In order to draw conclusions about the movement of great apes, a lot of digging would need to happen in modern Turkey. Unfortunately, this step is not straightforward either. An entire forest does not fossilize that easily. It is important for scientists to then investigate the indirect evidence of afforestation to find more clues.

A practical example of this kind of indirect evidence is the teeth of herbivores. The teeth of herbivores are divided into two groups: grass-grinding teeth and fruit-grinding teeth. The main difference is the length of the crown (the visible part of a tooth). The crown of grass-grinding teeth is a lot longer than that of fruit-grinding teeth because prolonged chewing of grass causes much more wear than chewing of fruit.

Because of these characteristics, on grasslands you will find mostly herbivores with grass-grinding teeth, such as horses and cows. In forests, on the other hand, you will find mostly animals with fruit-grinding teeth, like monkeys and pigs. So, if excavations in Turkey would almost exclusively produce grass-grinding teeth, it would mean Anatolia used to be almost completely covered in grasslands. Which almost certainly made European great apes extinct in Europe. On the other hand, if fruit-grinding teeth are more commonly found, Anatolia would have been at least partially forested. Which would make it very likely that the European great apes reached Africa.

Difference between the tooth of a human (a) and the tooth of a grass eater (b)

It is also quite possible that these great apes were the last shared ancestor for us humans and chimpanzees, but no definitive statement can be made about this. At least not until extensive excavations are done in Turkey. Although there are still many questions and unknowns regarding the evolution of humans and their relatives, Yanell Braumuller's research seems to shed some light on this story.

References
Braumuller, Y. (2024). Bionieuws Symposium, Leiden, Nederland. Bruch, A. A., Uhl, D., & Mosbrugger, V. (2007). Miocene climate in Europe — patterns and evolution. Palaeogeography, Palaeoclimatology, Palaeoecology, 253(1–2), 1–7. https://doi.org/10.1016/j.pala... Most recent European great ape discovered. (2012, 12 januari). ScienceDaily. https://www.sciencedaily.com/r... ADW: The Diversity of Cheek Teeth. (z.d.). https://animaldiversity.org/co...

Images
A new ape from Türkiye and the radiation of late Miocene hominines
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