A group of researchers from France, Italy and the United States have provided evidence that the earliest human ancestor of the species Sahelanthropus tchadensis was not actually a hominid and, therefore, cannot be the oldest member of our species.
The study was published in the Journal of Human Evolution and briefly covered by Phys.org. The work of an international team of authors is able to end the scientific debate about the place of Sahelanthropus tchadensis on the evolutionary tree.
The fossilized remains of this humanoid creature were discovered in the Jurab Desert in Chad in 2001. The discovery was then made by a small research group CNAR. It was a species unknown to science, which was named Sahelanthropus tchadensis.
The team examined the recovered remains and came to the conclusion that their age ranges from 6.8 to 7.2 million years. The sensation was the statement of these researchers that the creature found was an upright hominid. Hence, this was one of the ancestors of man. At that time, our oldest ancestor was considered “Lucy” – the famous hominid about 3.2 million years old.
However, the statement about Sahelanthropus tchadensis has raised doubts among many scientists. First, the evidence the research team then reported was based on a study of … teeth and markings on the back of the skull. Second, the work was published in a journal that has not been peer-reviewed. Third, the team refused to give other scientists access to the fossils it found.
And only two decades later, a new study was carried out that may help uncover the secret of Sahelanthropus tchadensis. The authors of the work claim that they managed to find evidence that the mysterious creature was not upright, therefore, was not a hominid, but was the ancestor of monkeys.
In this case, the study is based on the analysis of the fossilized femur and looks more reliable than the results of the analysis of the teeth. The researchers write that it was a creature that moved on four limbs, just like gorillas and other great apes do today.
The authors of the paper believe that the size of the teeth, which was the subject of research by the previous team, is not sufficient evidence that Sahelanthropus tchadensis is a hominid. In their opinion, the teeth may have belonged to a small female monkey.
Overall, the researchers concluded that Sahelanthropus tchadensis was not a hominid and therefore can no longer be called one of the first human ancestors.
However, it should be noted that in the new study, scientists did not study the fossils that were at the disposal of their predecessors. Part of the femur they studied was found near the site where the remains of Sahelanthropus tchadensis were found in 2001.
Since the sites of the finds are very close, and the age of the fossils is practically the same, the scientists considered that the remains of the same long-dead representative of the species Sahelanthropus tchadensis fell into their hands.