Nearly two decades ago in the Djurab desert in the northern part of Chad, French paleontologists unearthed a 6-to-7-million-year-old hominid species called Sahelanthropus tchadensis that they named “Toumai”. Ever since then, it was believed that it was the earliest known human ancestor. New studies, however, have challenged that very theory.
Anthropologists from the University of Michigan in Ann Arbor claimed that the skull belonged to a female ape. Professor Milford Wolpoff and his colleagues argued that there wasn’t any evidence that proved Toumai walked on two legs. “Toumai may be a common ancestor of apes and humans but it is not on the line directly leading to humans,” he said, adding, “We think Toumai is an ape and we think it’s probably a female because of its canine teeth.” While her teeth were small like a human’s, they were also similar in size to those of chimpanzees or female gorillas.
Additionally, the scars on her skull that were created by the neck muscles indicated that her head was horizontal to her spine as she walked on all four legs. A femur bone was found as well and its shape suggested that it belonged to a primate.
These are certainly conflicting theories. The bones were discovered in 2001 by Michel Brunet who claimed that it was bipedal and that its skull would have been connected to an upright spine. This would mean that Toumai was approximately twice as old as “Lucy” who dates back to around 3.2 million years ago.
However, things got interesting when it was revealed that a left femur and two forearm bones that were discovered were never published by Brunet which some believe was very suspicious as they would have proved that the remains belonged to a primate instead of a human.
In fact, when a researcher from the University of Poitiers named Aude Bergeret-Medina came across Toumai’s femur, she took several photos and measurements of the bone before it mysteriously went missing and she never got to examine it again. That’s when she and her mentor, palaeoanthropologist Roberto Macchiarelli, decided to write their own report on how their findings suggested that Toumai wasn’t bipedal and their paper will be published in the December issue of the Journal of Human Evolution.
Alain Beauvilain, who is a geographer that helped with the unearthing of Toumai, has raised his own concerns about when and where the remains were discovered. Perhaps the locals may have once disturbed the remains.
On the other hand, Michel Brunet and paleontologist Franck Guy are still convinced that the remains did belong to a bipedal species. Guy stated that near the top of the femur bone there was a hard ridge which suggested that it was in fact bipedal.
It appears as though the debate is far from over. Pictures of the bones and the skull can be seen here.