They conclude that the oldest ancestor of humans was the biped.

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[3D models of fossils of the species sahelanthropus tchadensis]. Ed. © Franck Guy / Palevoprim / CNRS – University of Poitiers

Researchers from the French Scientific Research Centre (CNRS) claim that the oldest ancestor of the human lineage, Sahelanthropus tchadensis, was on two feet. There are few fossils of this species, and one of the best known is a skull, the Toumaï. It is about 7 million years old, was discovered in Chad in 2001 and has sparked strong discussions among experts. At first, for example, it was discussed whether he was hominine with serious doubts and whether he was able to walk upright. Now, in the research they've published in the journal Nature, they've shown that yes, they've been able to walk standing and ascend through the trees held in their hands.

The position of the skull in relation to the spine leads to suspicion that he was going to stand. Now, CNRS researchers have been able to study the fossils of the extremities (one femur and two cubits) and have confirmed this suspicion. In particular, external morphology and internal structures of these bones have been studied by microtomography. Thus, biometric measurements, geometric morphometry and biomechanical indicators have been obtained, comparing them with current samples of apes and fossils such as chimpanzees, gorillas, orangutans, Miocene apes and human lineage.

Taking also into account the skull, they have come to the conclusion that he was able to walk standing on two feet, ascending through the trees, grabbing with his hands, as we humans do (gorillas and chimpanzees ascend on the back of the falanges).

For many experts, bipedism is a clear characteristic to be considered hominine, but CNRS researchers have clarified that they have not analyzed it in their research, but have limited themselves to investigating locomotion.