Our ancestors walked upright seven million years ago

Seven million years ago, our oldest ancestors were probably already walking upright in the territory that is now occupied by Chad.

The first evidence to suggest it was unearthed in 2001: several fossil remains, including a very well-preserved skull of a species that was named

Now, a new and detailed analysis of three limb bones found nearby and attributed to the same species because no primate remains had been found there (although it is not known if they are from the same individual to which the skull belonged), provides new arguments. that would support that this ancestor, the oldest that would have been found so far, could walk on foot, as confirmed by a team of researchers from France (from the CNRS and the University of Poitiers) and Chad in an investigation published this Wednesday in the journal

and led by Guillaume Dave.

The ability to stand upright, that is, bipedalism -or bipedalism as collected by the RAE, is considered a decisive step in human evolution, but there is no consensus among paleontologists about at what point in our history or how our ancestors began to walk standing.

And it is that in the study of human evolution it is difficult to make resounding affirmations.

The remains that are usually found are scarce, partial -a few bones of the skeletons or even a single fossil- and due to their age, they are not always in a good state of conservation, so the interpretations and their classification are often debated or questioned by other paleontologists.

This is what happened in 2001 when Michel Brunet and his colleagues published the discovery of the skull of the genus and species that they themselves proposed,

in the Djurab desert

As José María Bermúdez de Castro, co-director of the Atapuerca sites (Burgos), recalls,

, based on the basal position of the foramen magnum, where the head and spine.

However, it was a much debated conclusion: "I was fortunate to attend one of Brunet's talks at a congress in Beijing in 2004. He was very upset with the doubts of his colleagues. Without a doubt, Brunet was the great attraction of that congress. 21 years have passed and now this work is published. I know that there have been many problems among certain paleoanthropologists with the interpretation of the other fossil remains found next to Toumeï. The controversies end up arriving without you intending it in your inbox of your mail. And it seems that the supporters of

bipedalism have won ", reviews Bermúdez de Castro, without connection with this study.

The three limb bones on which this new research is based were subjected to a battery of analyzes to study their external and internal structure (using imaging techniques such as microtomography).

from chimpanzees, gorillas, orangutans, Miocene primates, and also from members of human ancestors such as

,

, Australopithecus, archaic humans, and

).

The authors argue that the structure of the femur indicates that

was normally bipedal when walking on the surface but also in trees.

, but in a different way than gorillas and chimpanzees did.

"Certainly, and if the conclusions of this work are correct, ToumeÏ (or rather,

) would be the oldest representative of human genealogy, since

", Bermúdez de Castro specifies.

As the paleoanthropologist contextualizes, "all our Pliocene ancestors [from approximately 5.3 million years to 2.6 million years ago] had the ability to maintain an upright posture like ours, although evidence from members of the

(4.4 million years ago) - for example - didn't have the ability to run like we do."

All these ancient species, adds the researcher, "retained the ability to climb easily, since their habitat was more or less leafy forests. So, if the conclusions of Daver and his colleagues are correct,

.

The famous Lucy - the

- walked upright 3.2 million years ago.

Precisely the researchers who have signed the study on

have dedicated the research to one of Lucy's parents

French paleoanthropologist Yves Coppens, who died last June, for his pioneering work in the Djourab desert.

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