Anthropologists announced a new study providing strong evidence that a seven-million-year-old fossil, Sahelanthropus tchadensis, was bipedal, potentially rewriting the timeline of human origins. The research, conducted by scientists at New York University and the University of Alabama Birmingham, suggests that this ancient hominin, despite its ape-like features and small brain, possessed the ability to walk upright.

The study focused on anatomical analysis of the fossil, specifically examining the femur (thigh bone) and ulna (forearm bone). Researchers identified a ligament attachment site on the femur that is characteristic of bipedal species, indicating that Sahelanthropus tchadensis likely moved with confidence on two legs. "This finding places bipedalism near the very root of the human family tree," said Scott Williams of NYU, one of the lead researchers on the project.

For decades, the question of Sahelanthropus tchadensis's locomotion has been a subject of intense debate among paleoanthropologists. The fossil, discovered in Chad in 2001, dates back to a period close to the hypothesized split between the chimpanzee and human lineages. If confirmed as bipedal, Sahelanthropus tchadensis would represent the earliest known human ancestor, pushing back the origins of upright walking by millions of years.

The implications of this discovery are significant for our understanding of human evolution. It suggests that bipedalism may have evolved earlier and more rapidly than previously thought, potentially driven by environmental pressures or other factors that favored upright posture. This challenges existing models that often link bipedalism to specific environmental changes in East Africa.

Jason Heaton of the University of Alabama Birmingham, another lead researcher, noted that further research is needed to fully understand the locomotion of Sahelanthropus tchadensis. "While the evidence for bipedalism is compelling, we need to consider the entire skeletal structure and the environment in which this hominin lived," Heaton stated. Future studies will likely focus on analyzing additional fossil fragments and conducting biomechanical simulations to reconstruct the gait of Sahelanthropus tchadensis. The findings were published in a recent issue of a peer-reviewed scientific journal.