A mysterious foot fossilization discovered in Ethiopia suggests the existence of a hitherto little-known ancestor of man, a contemporary of the famous Lucy species.
Until now, Lucy’s species, Australopithecus afarensis, was considered the only ancestor of man who had lived in this region more than three million years ago.
However, this 2009 discovery in Burtele, northeastern Ethiopia, could even call into question Lucy’s status as a direct ancestor of “Homo sapiens,” according to a scientific study published Wednesday in the journal Nature.
The foot found does not belong to Lucy’s species, since it has an opposable toe, similar to a thumb, which allows it to cling to tree branches, like monkeys.
The scientists who discovered the bones of this limb deduced in 2015 the existence of a previously unknown species of hominid, the “Australopithecus deyiremeda”based on jaws approximately 3.4 million years old also found at Burtele.
Until now, the team could not say with certainty that the bones of this “Burtele’s foot” belonged to this new species.
But in this study published in Nature, scientists announce that new fossils, including a jaw with 12 teeth found at the site, show that the foot was from an “Australopithecus deyiremeda”.
“We have no doubt that Burtele’s foot belongs to the same species as these teeth and this jaw,” the study’s lead author, Yohannes Haile-Selassie, from the University of Arizona, explains to AFP.
Ancestor of Homo sapiens?
Researchers discovered new evidence of a link between this species and Homo sapiens.
A scan of the exposed teeth suggests that “Australopithecus deyiremeda” was more primitive than its relative Lucyaccording to the study. Their diet consisted mainly of leaves, fruits and nuts from trees.
Its prehensile big toe also suggests that this relative of Homo sapiens spent more time in trees.
These fingers played an important role in human evolution, since they indicate that the man left the trees and started walking with two legs.
The possible coexistence between “Australopithecus deyiremeda” and Lucy’s species continues to be a topic of debate among scientists.
The new research suggests that the species “Australopithecus deyiremeda” spent its time in the forest, often in the trees, while Australopithecus afarensis like Lucy were more on the ground, a difference that allowed them to coexist, according to the researchers.
This shows that “coexistence is deeply rooted in our ancestry,” Haile-Selassie notes.
In search of the roots
John McNabb, an archaeologist specializing in the Paleolithic at the University of Southampton, welcomed this new research.
“There will always be skeptics, but I believe that these new discoveries, together with the validation of previous ones, will help many researchers to better accept ‘Australopithecus deyiremeda’,” says this scientist, who was not involved in the Nature study.
This “adds a new element to the equation” in the search for the identity of our true ancestor, he says.
Lucy’s species remains the most important ancestor, because her foot is closer to that of mancompared to the more primitive “Australopithecus deyiremeda”, the two scientists admit.
But this discovery “opens up the possibility that we may still be able to find other species dating from this period, as it appears that Australopithecines were experimenting with being bipedal,” insists Haile-Selassie.
For a long time, Lucy, found in 1974, was considered the oldest ancestor of humans found, but she was dethroned in 1994 by Ardi, a female “Ardipithecus ramidus” who lived 4.5 million years ago also in present-day Ethiopia.