Paleontology: When early humans started walking on two legs | Nature | nature wallet

Sahelanthropus tchadensis, one of the oldest known hominins (Sahelanthropus tchadensis) was bipedal 7 million years ago, according to analysis of femur and forearm fossils. The results build on previous analyzes that came to similar conclusions. Reporting sheet for this researchtemper nature It will be published in

In 2001, a large number of fossils were discovered in Talos Menara, Chad, resulting in the naming of a new species of early hominin (a classification that includes extinct species closely related to modern humans), Sahel Chadensis, dating from approximately The hominin race is 7 million years old. Analysis of the nearly intact skull also indicates that Sahelanthropus may have walked on two legs, a hallmark of hominins that is “upright motion on two legs.” Regarding this hypothesis, a research report of arm and leg bones excavated in the same area was already reported at about the same time, and we had the opportunity to verify this using it.

Guillaume Daver, Frank Jay and their colleagues presented results of an analysis of a left femur and a pair of forearm bones (ulna) from the site where the Sahel fossil was found in 2001. Anatomy of the femur indicates that Sahelanthropus walked on two legs on Earth about 7 million years ago, which Confirms predictions made by the evidence of the skull. In addition, Daffer and colleagues cautiously assert that ulnar features are compatible with features characteristic of tree-climbing adaptations. For example, the functional pattern of the ulna indicates that the Sahelanthropus ascended and descended trees, possibly by some form of grasping or irregular limb movements.

Taken together, the evidence suggests that shortly after humans and chimpanzees diverged, early humans acquired the ability to walk on two legs and retained the skeletal traits that enabled them to climb trees. Daffer et al. conclude that they do.

doi: 10.1038/s41586-022-04901-z

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