Oldest human remains outside of Africa could push back the history of human evolution 100,000 years


The longstanding consensus among scientists is that modern humans gradually replaced Neanderthals until they became extinct after a single migration from Africa. But a new discovery out of Greece is changing everything we thought we knew.

Back in the late 1970s, researchers exploring the Apidima Cave in Southern Greece found a pair of ancient skulls that were written off as Neanderthal skulls at the time, and no other thought or attention was given to them for decades and the prevailing theory about human evolution and migration remained unchanged.

That is, until now.

A team of paleoanthropologists led by Katerina Harvati of the Eberhard Karls University of Tuebingen, Germany took a new look at the skulls using modern technology and made a stunning find that truly changes our understanding of early humans and Neanderthals.

Homo sapiens are supposed to have migrated out of Africa no more than 200,000 years ago and they didn’t go very far.

But the skulls tell a very different story. Dubbed Apidima 1 and Apidima 2, the research team conducted tests to determine which human species they belong to and how old they are. Apidima 2, they concluded, is a Neanderthal skull dating back to 170,000 years ago, which makes sense. But Apidima 1 is the surprising result because it came from a Homo sapien dating back 210,000 years.

According to the study published in Nature:

Two fossilized human crania (Apidima 1 and Apidima 2) from Apidima Cave, southern Greece, were discovered in the late 1970s but have remained enigmatic owing to their incomplete nature, taphonomic distortion and lack of archaeological context and chronology. Here we virtually reconstruct both crania, provide detailed comparative descriptions and analyses, and date them using U-series radiometric methods.

Apidima 2 dates to more than 170 thousand years ago and has a Neanderthal-like morphological pattern. By contrast, Apidima 1 dates to more than 210 thousand years ago and presents a mixture of modern human and primitive features. These results suggest that two late Middle Pleistocene human groups were present at this site—an early Homo sapiens population, followed by a Neanderthal population. Our findings support multiple dispersals of early modern humans out of Africa, and highlight the complex demographic processes that characterized Pleistocene human evolution and modern human presence in southeast Europe.

 

This is a groundbreaking result. Apparently, humans lived in this area of Greece before Neanderthals moved in tens of thousands of years later.

“It shows that the early dispersal of Homo sapiens out of Africa not only occurred earlier, before 200,000 years ago, but also reached further geographically, all the way to Europe,” Harvati told Phys.org this week. “This is something that we did not suspect before, and which has implications for the population movements of these ancient groups.”

 

Harvati hypothesized that these early Homo sapiens died off and were replaced by Neanderthals.

“We think that these early migrants did not actually contribute to modern humans living outside of Africa today, but rather died out and were probably locally replaced by Neanderthals,” she said in a press release. “We hypothesize this is a similar situation with the Apidima 1 population.”

However it’s also possible the Homo sapien population moved on because of the climate, as The Conversation pointed out:

Specimens from sites in the Levant (modern day Israel, Syria, Lebanon and Jordan) suggest the first wave of modern humans out of Africa were replaced by Neanderthals, before the final, more successful human migration later on.

The new data from Apidima further extends this complex picture of modern human dispersal and interaction with other hominin species. For example, the earlier human skull came from a time when the surrounding environment was warmer and wetter than the cold and arid conditions the later Neanderthal specimen would have lived in. This emphasises that our explanations for population dispersals need to take into account the context of major environmental change and the opportunities and challenges that went with it.

It makes sense. Humans were more susceptible to colder weather because we were used to the drier and warmer climate in Africa. So when the climate became colder in Greece, humans moved on and the Neanderthals moved in, having the benefit of hairier bodies for increased warmth.

And we now know the Neanderthals could regularly make fire and used it to melt resin they used as glue to construct tools with handles. So, they could prevent themselves from freezing to death.

But the study proves that there must have been multiple migrations of Homo sapiens out of Africa and into Europe, which gradually displaced Neanderthals over time and eventually wiped them out. And our own DNA proves that interbreeding was part of this gradual overthrow.

“Rather than a single exit of hominins from Africa to populate Eurasia, there must have been several dispersals, some of which did not result in permanent occupations,” City University of New York professor of anthropology Eric Delson, who did not participate in the study, said.

This also makes sense because not every settlement is successful. People abandon sites for one reason or another, and climate change is as good a reason as most. After all, climate change is causing human migration today from hotter regions into Europe and North America, giving us an active example of how climate can affect human dispersal.

In the end, it turns out we still have a lot to learn about our human ancestors and technology will be key to unlocking that knowledge.

“I think recent advances in palaeoanthropology have shown that the field is still full of surprises,” Harvati concluded.

And this research could not be more timely as climate change and migration become major issues in our own time.

 

See more in the video from Tomo News below:


Featured Image: Eberhard Karls University of Tübingen


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