An old skull 1, 8 million years upsets the history of ... - Maxisciences

In Georgia, researchers found an old skull of 1.8 million years. This discovery calls into question the entire history of human evolution because it suggests that the hominids of the time, whether in Europe or Africa, belonged to a single species.

if scientists were wrong about the evolution of the ? As surprising as it may seem, it is indeed that suggests a new study by Swiss and Georgian researchers in the journal Science . The origin of this work: an old skull 1.8 million years discovered in Georgia, in a village called Dmanisi. This is one of the oldest known to have been inhabited by the ancestors of Man websites once they come out of Africa.

Archaeologists have also unearthed at Dmanisi the most comprehensive collection of bones, skulls and jaws of Homo erectus . The new skull found there five years now, is the best preserved fossil of a human ancestor known to date. Called “skull 5″, it was found next to the remains of four skulls, all related to the same place and at the same time. However, the fossil presented quite amazing features, similar to those of the same period found in Africa features.

However, scientists do not expect this similarity. In fact, modern humans, or Homo sapiens is currently the only living member of the Homo lineage appeared on Earth in Africa there are about 2 million years . However, before that Homo sapiens makes its appearance, several other species of Homo have existed such that Homo habilis , Homo rudolfensis Homo ergaster or Homo erectus .

Several species are but one

that estimated that at least now the majority of scientists in the light of the many discoveries made so far. But the “skull 5″ completely upset this theory and suggests that there would have been several hominids present at that time in Africa and Europe, but a single global species. Indeed, the researchers found that the skull had a long face, a massive jaw and large teeth, all associated with a small skull.

According to the study, it would be approximately one-third of that found in modern humans and would not be bigger than the most primitive African fossils. This is the first time that such a combination of characteristics is observed on a fossil of Homo . The level of variation in a fossil to another is normally used to define separate species. But scientists believe that the differences observed between the skull and five other four are not so important.

“ Dmanisi individuals all belong to a population of a single species of Homo . five Dmanisi individuals are significantly different, but not more than five different modern individuals or five chimpanzees a given “population, said Christoph Zollikofer, the Institute of Anthropology at the University of Zurich.

Homo erectus in Europe and Africa

In their study, the scientists also investigated the existing level of variation in Homo fossils found in Africa. They found a level comparable to that observed in the Dmanisi fossils diversity. According to the researchers, the fossil is therefore not translate the existence of several different species in specific habitats but variants of a single line that would have emerged in Africa and that would have been able to specialize in a variety of habitats.

“ What we can infer from our study Dmanisi is there to 1.8 million years ago, there was another unique human species and global ” like to Homo sapiens today said Zollikofer LiveScience . But then what kind was it? “ We think it makes sense to assign all specimens Homo erectus,” he added as the researcher Georgian fossils have long legs and narrow hips that bipedalism sign.

But researchers remain moderate: they do not offer to assign all the fossils found Homo erectus . “We only talking about the period dating from there to 1.8 to 2 million years ,” said Zollikofer. Homo erectus appeared there would be two million years ago in Africa. He would then spread to Eurasia, via Georgia, China and Java, where the oldest traces have been found dating back to 1.2 million years.

This discovery sparks debate

Not surprisingly, this new discovery divides researchers. Ian Tattersall, paleoanthropologist interviewed by LiveScience is a fantastic discovery, but is not really convinced. “ This is the most extraordinary and significant specimen” not found. But “I think it is a mistake to impose Homo erectus in the interest of maintaining a linear image of human evolution. The specimen is in fact very different from a morphological point of view, and highlights that human evolution has involved a strong diversification and experimentation potential hominid “.

Asked by BBC News, Fred Spoor of University College London believes him that the analytical methods used to study the skulls were not effective enough to ensure that they belong to the same species. “ They made a very general analysis of the skull shape that describes the shape of the face and skull with general and abusive terms “, he has said. Similarly, Chris Stringer of the Natural History Museum in London has doubts about belonging to the species Homo erectus.

team did a good job with “ this remarkable new skull and jaw huge ” image of the natural variation in the population of Dmanisi. But classify all fossil species under Homo erectus is difficult. “ Creatures began using tools and eating meat, and this has led the evolution. But I think it also generated the diversity. Dmanisi group is an example of the species that have emerged it and then continued by spreading throughout the old world . “

(Photo Credit: Georgian National Museum)

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