They reveal the face of the new "missing link" that could change theories about human evolution

Acquiring new knowledge does not always allow you to see things more clearly. Learning less frees the imagination and allows you to create more elegant explanations, even if they are closer to the truth. This is what happens with the study of human evolution, says Antonio Rosas. "The more we have information about evolutionary processes, more complicated they seem, " says the researcher of the Spanish National Research Council. This Thursday, a paleontological jewel was presented. It shows the face of one of our ancestors and becomes a new puzzle of a past that seems more and more complex.

The fossil is an almost complete skull of a hominid who lived 3.8 million years ago in the present afar region of Ethiopia. He found it in 2016, in the Woranso-Mille area, under the direction of Yohannes Haile-Selbadie, an Ethiopian researcher at the Cleveland Museum of Natural History. After three years of studies, two articles were published in the magazine Nature in which it is said that it is an Australopithecus anamensis, an ancestor of Lucy, the fossil of an Australopithecus afarensis, became famous as the first known hominid who had begun to to walk upright.

Humanity was created over millions of years, of which Africa was the main theater. There, some monkeys began to leave trees driven by weather changes or competition with other animals and stood up to travel long distances in search of hands-free resources to create the technology. In the history of this history, until recently, some scientists have defended the fact that some species engendered others, in a linear succession that would lead to us, the summit of creation. The MRD skull, like Australopithecus anamensis known to Woranso-Mille is known, complicate this part of the story.

The fossil age of 3.8 million years indicates that anamensis have lived with their afarensis descendants for 100,000 years. This calls into question the hypothesis, postulated until recently by Haile-Selbadie himself, that one species engenders another and that its appearance signifies the disappearance of the ancestral race. "This discovery alters the idea of ​​a linear evolution of an older spice in a more modern, but the fact that they are together is not inconsistent with the fact that one is the ancestor of the other, "Rosas says.

Haile-Selbadie does not want to speculate on the possibility that, as for different human species such as Neanderthals, Denisovans or Sapiens, these two species had bad and descendantsbut the similarities confirmed by the new skull suggest that it would not be far-fetched.

Anamensis are not the first hominids to have started walking on their feet. Other species such as Ardi, who lived 4.4 million years ago also in Ethiopia, or Sahelanthropus tchadensis, a species over 6 million years old found in Chad. , have already started to get up. But they still spent a lot of their lives hanging trees. The anamensis, as pointed out Luis Gibert, researcher at the University of Barcelona and co-author of one of the articles that he publishes Nature, they lived ina rather arid environment, dominated by shrubs and grbades rather than forests. "Although he continues to climb trees, the conditions of his world urge him to walk much more frequently and their fossils suggest that they would be much better able to do so."

The owner of the skull presented by the specialized magazine lived in a kind of savannah somewhat different from the vast plains of African Memories, according to Manuel Domínguez Rodrigo, co-director of the Institute of Evolution in Africa of the University of Alcalá de Henares. "These are savannas where there are open spaces and wooded areas and where access to food depends on the seasons.These are very different places from the jungle.The fruits are rarer and can not be obtained that at times, which led them to diversify their diet, because of the teeth of this skull, wider and with a thicker enamel, he also forced them to move more and the biped is very effective for long distances and save energy, "he says.

The new skull shows us an evolution that seems almost tortuous compared to the linear approach of a primitive species to which a more modern species occurs. MRD had a face very similar to that of his afarensis descendants, but the back of the skull looks something of the past and recalls that of the most primitive Sahelanthropus. With a cranial capacity of about 370 cubic centimeters, it is close to chimpanzees and, in this tiny skull, shares a dash with these animals. Their canines have, in proportion, a large size. "This is an indicator of badual dimorphism, He tells us that his breeding strategy is not monogamous but quite the opposite. Males compete to breed between chimpanzees and gorillas, "explains Domínguez Rodrigo.

The small size of the skull also opens new mysteries. The height of this individual should not exceed much the meter, which does not correspond to the meter and a half, similar to the males of the species of Lucy, calculated for other members of the family of the MRD to from a shin fossil. attributed to his species. There will always be the doubt of the representative of his species who has been this individual whose skull has been fossilized, virtually completed, for nearly four million years.

The modern era begins with the fall of Constantinople and the Neanderthals are completely different from the sapiens. But the reality is revealed much more complicated and does not stay in order on the shelves. It seems that the evolution created many prototypes of these ancestral hominids, with features and interlaced steps. When chimpanzees have separated from our lineage, it is possible that a little later, the species supposedly more advanced hybridize with the primitive.

"As we have more information, simple ideas are no longer used to explain the diversity we find," Rosas admits. "To have simple and elegant ideas again, I think it will not be worthwhile to find more fossils. We need a more sophisticated theoretical framework, "he continues. As physicists pursuing Einstein's dream, a theory of unification that manages to explain the universe once and for all, anthropologists seek the explanation that will help them make sense to millions of years tests that gave rise to a species capable of asking so many questions.