28.08.2019 at 19:50
"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 in the journal Nature.
An asset that could earn him "to become a new icon of human evolution," Judge Fred Spoor of the Natural History Museum in London in a comment. And to join the famous "Toumaï", "Ardi" and "Lucy".
For comparison, "Toumaï" (a Sahelanthropus tchadensis), considered by some paleontologists as the first representative of the human lineage, is about 7 million years old. It was unearthed in 2001 in Chad.
Ardi (for Ardipithecus ramidus, another species of hominid) discovered in Ethiopia would be 4.5 million years old and "Lucy", the famous Australopithecus, discovered in Ethiopia in 1974, 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. Without "old" skull, our understanding of the evolution of these extinct hominids was very partial.
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 Australopithecines, called Australopithecus anamensis.
– " dream come true " –
"We thought that A. anamensis (MRD) was gradually turning into A. afarensis (Lucy) over time," says Stephanie Melillo of the Max Planck Institute for Evolutionary Anthropology in Germany, co-author of both studies.
But this last discovery raises the dice, revealing that the two species would have crossed in the savannas of the Afar for about 100,000 years.
"This changes our understanding of the evolution process and raises new questions: were they competing for food or space? Asks Stephanie Melillo.
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.
"It's good to finally put a face on a name," enthuses the paleoanthropologist.
To the surprise of the researchers, the skull turns out to be a mixture of characteristics specific to Sahelanthropus like "Toumaï" 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".
The fossil at first only hinted at his jaw, "I did not believe my eyes when I saw the rest of the skull" recalls Yohannes Haile-Selassie who describes a moment "eureka", "a dream become reality ".