A 3.8 million-year-old skull gives a face to an ancient species of Australopithecus


This skull discovered in 2016 belongs to an "Australopithecus anamensis", which could have coexisted with the "Australopithecus afarensis", which includes the famous Lucy.

A bone ridge, large canines and a robust constitution. A 3.8 million year old Australopithecus skull was found in Ethiopia. "This skull is one of the most complete fossils of hominids more than 3 million years old", says Yohannes Haile-Selassie of the Cleveland Museum of Natural History (USA), co-author of two studies published Wednesday (August 28th) in the journal Nature.

As a comparison, Toumaï (a Sahelanthropus tchadensis), considered by some paleontologists as the first representative of the human lineage, is about 7 million years old. Ardi (for Ardipithecus ramidusanother species of hominid) would be 4.5 million years old and Lucy, the very famous Australopithecus, is 3.2 million years old. Other lesser-known Australopithecus fossils date back at least 3.9 million years, but only jaws and teeth were found.

Discovered in February 2016 on the site of Woranso-Mille, in the Afar region of Ethiopia (55 km from where Lucy was discovered), this new fossil, called MRD, belongs to one of the earliest Australopithecus, called Australopithecus anamensis. This species has been "proposed in 1995 by paleoanthropologist Meave Leakey after the discovery of 21 fossil fragments " in Kenya, specifies The world. But nothing yet allowed to visualize the characteristics of his head.

"We thought that Australopithecus anamensis was gradually turning into Australopithecus afarensis (Lucy) with time"says Stephanie Melillo of the Max Planck Institute for Evolutionary Anthropology in Germany, co-author of both studies. But the discovery raises the dice: the two species would have crossed in the savannas of the Afar during about 100,000 years. "This changes our understanding of the evolution process and raises new questions: were they competing for food or space?"wonders Stephanie Melillo.

Quoted by Le Monde, the paleoanthropologist Yves Coppens, co-discoverer of Lucy reminds us that evolution is not necessarily linear. For him, it is possible thatome anamensis have given afarensis, "while others anamensis continued on their way to their extinction

Even if it is very small, the skull must be that of an adult, a priori masculine. Facial reconstructions made from the fossil features show a hominid with cheekbones projected forward, prominent jaw, flat nose and narrow forehead. To the surprise of the researchers, the skull turns out to be a mixture of characteristics peculiar to Sahelanthropus like "Toumai" and to Ardipithecus as Ardi, but also to others of more recent species. "Until now, there was a big gap between the oldest human ancestors, which are about 6 million years old, and species like 'Lucy', which are two to three million years old.", tells Stephanie Melillo for whom this discovery "links the morphological space between these two groups".

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