Wiseman LA. 2023 Three-dimensional volumetric muscle reconstruction of the Australopithecus afarensis pelvis and limb, with estimations of limb leverage. R. Soc. Open. Sci. 10:2303556.
https://royalsocietypublishing.org/doi/10.1098/rsos.230356
Researchers have reconstructed the muscle mass ofAustralopithecus afarensis Lucy, dated at 3.2 million years. This one, discovered in 1974 at the Hadar site in Ethiopia, provided us with a very complete skeleton, with almost 40% of the bones found. The various studies carried out on Lucy’s skeleton have shown that she was certainly capable of bipedalism, while continuing to climb trees to get around. However, these studies were carried out on bones, not muscles. Although researchers have been trying for some years to reconstruct the muscles of certain Hominins in order to deduce elements about their locomotion, this approach was limited by the complexity of the mathematical models to be set up.
In this new study, researchers try a new approach to reconstruct 36 muscles of the Australopithecus pelvis and lower limbs. To do this, they used the anatomy of Homo sapiens individuals to infer muscle positioning in Lucy. This new 3D model of Lucy’s muscles shows that she had much more massive and developed muscles than today’s Homo sapiens. What’s more, the study shows that, although certain muscles were positioned differently in Australopithecus than in our species, they enabled Lucy to stand in an erect position. However, his bipedalism differed from ours in the positioning of certain muscles. It was also capable of other modes of locomotion, such as arboricolgy.