Scientists in Switzerland have found that humans and chimpanzees have very similar muscle attachment sites at their thigh bones, which could have major consequences for the interpretation of fossil hominin findings.
In a study published in the scientific journal Anatomical Record, anthropologists found that although humans are bipeds and chimps are quadrupeds, the muscle attachment sites are more similar than those between chimpanzees and gorillas, despite the great ape species moving more similarly.
Anthropologist Christopher Zollikofer explained that many fossil thigh bone shafts are well preserved, so inferences about locomotor behaviour must now be "drawn with caution", while thoughts on the fossil's evolutionary relationships could be more straightforward.
"The transition from great-ape-like quadrupedal to human-like bipedal locomotion is accompanied by several changes in the hip and thighbones, but currently we cannot infer functional change from structural change with any certainty," he noted.
The expert added that further study will determine why the last common ancestor of humans and chimpanzees, who lived seven to eight million years ago, evolved the novel thigh bone feature.
