March 1, 2021

Two skulls threaten to change the history of our species | Science

A pair of skulls found in a cave in southern Greece today raise information that would force the textbooks on human evolution to be thrown away, although many independent experts warn that it is too early to do so.

The two skulls were found in the seventies. They were inches from each other, embedded in the rock of the grotto of Apidima, on a cliff dotted by the waves of the Mediterranean. One of the skulls conserved the bones of the face and the other only the back of the head. At first they were attributed to Neanderthals, the premium human species of ours who occupied Europe for hundreds of thousands of years before mysteriously extinct 40,000 years ago, just when sapiens We arrive to the continent.

Now, a team of paleoanthropologists has re-dated the two skulls and reconstructed them in three dimensions to analyze their physiognomy in detail. The results, published today in Nature, point out that the oldest and most incomplete skull is 210,000 years old and is a Homo sapiens, which would make him the oldest member of our species ever found in Europe.

The proposal is a tremendous mandoble to the classic version and even the most accepted on the origin of our species. According to this version, sapiens They appeared in East Africa. Two of the oldest fossils of our species date back to 196,000 years and 160,000 years ago and were found in Ethiopia. The analysis of the DNA of current populations fixes on the origin of the species about 200,000 years ago.

The skull 1 of Apidima with part of sediment adhered, supposedly of a 'Homo sapiens' that lived 210,000 years ago, the oldest in Europe.

The skull 1 of Apidima with part of sediment adhered, supposedly of a 'Homo sapiens' that lived 210,000 years ago, the oldest in Europe.

DNA analysis has also shown in previous studies that about 100,000 years later, the sapiens They left for the first time from their African cradle to explore Eurasia. In that skirmish they met the Neanderthals and had children with them, but that wave of wise humans did not fully come together. None of the current people descends from them, but from a raid outside of Africa after about 70,000 years ago. This was the one that triumphed and populated the entire planet while the Neanderthals disappeared forever.

Two years ago, a team of paleoanthropologists stabbed at this classic story by presenting the fossils of Homo sapiens oldest known, from 315,000 years ago. They were found in Morocco, very far from the supposed cradle of our species. This breakthrough discovery makes possible what is now being proposed by the new study of the Greek remains, whose authors propose an amazing account of a hitherto unknown chapter of our history as a species.

In that story there is another key piece. The second skull found in Apidima, the one with the face. According to the new analysis, it dates back 170,000 years and belongs to a Neanderthal. This assumes that there was a group of sapiens He left Africa long before we knew it, he reached the south of Europe and settled there, although he finally lost the battle, as he was replaced by Neanderthals.

"That two skulls found a few centimeters from each other are from two different species separated by more than 40,000 years is novel," espers Arsuaga

The evidence that supports this story is a dating of the isotopes of uranium and thorium accumulated in the fossils and the morphological analysis of the two skulls. The oldest and most incomplete, number one, has been compared to dozens of remains of Homo sapiens and Neanderthals from different eras. According to the authors, it presents typical characteristics of our species, such as the absence of the occipital bun, a protuberance on the neck of the Neanderthals.

"If our analyzes are correct, the Homo sapiens they entered Europe more than 150,000 years earlier than we thought, which raises a lot of possibilities about the origin of our species and about what happened to them, "says Chris Stringer, a researcher at the Natural History Museum in London and co-author of the study. . The researcher recognizes that when they sent their study to Nature, one of the most prestigious scientific journals, "the reviewers were very skeptical that there was a modern human fossil found next to another Neanderthal one". Those responsible for the publication forced them to do more comparative analyzes and uranium dating that finally convinced them.

This study, together with other previous evidence, "shows that on more than one occasion modern humans ventured north and west of the planet from Africa to the Middle East and Europe," writes paleoanthropologist Eric Delson, of the National Museum of History. Natural of the United States, in an analysis of the Stringer team's study published by Nature. The work reveals the "failed migrations" of Homo sapiens, he says.

"Evidence is missing"

However, all experts consulted by Subject do not accept the conclusions of the study. "It is an extraordinary affirmation, but there is a lack of evidence to support it," he says. Juan Luis Arsuaga, co-director of Atapuerca. In 2017, this paleoanthropologist participated in the dating of uranium isotopes of skull 2, the most complete, which yielded a date of at least 160,000 years old. The researcher says that the morphology of the skull 1 is totally compatible in reality with that of a primitive Neanderthal who had not yet developed its typical characteristics in the back of the skull. "That two skulls found a few centimeters from each other are from two different species separated by more than 40,000 years is novel, I do not believe the new data and we are going to replicate this study," says the paleoanthropologist.

Warren Sharp, of the Center of Geochronology of Berkeley (USA), points out that the dating of skull 1 "does not hold". "The different individual dating obtained for this fossil diverged from 335,000 years ago to 142,000 years ago, suggesting that the fossil lost part of the uranium it originally had. This implies that the age they give is too old, "he explains.

Amélie Vialet, researcher at the National Museum of Natural History of France, believes that "the most plausible explanation is that the two skulls were trapped in the sediments of the cave at the same time and that both are Neanderthals".

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