[ad_1]
A new report challenges the theory that Sahelanthropus tchadensis, a hominid that lived over 6 million years ago, was our oldest known human ancestor.
French paleontologists discovered a Sahelanthropus in Chad almost two decades ago.
Nicknamed it “Toumai,” they announced that the creature was an early bipedal – with a skull indicating it had an erect spine.
But a new report suggests that Toumai is just an ancient primate, more closely related to a chimpanzee than a human.
The researchers base their claim on the shape of the femur, which they say belongs to Toumi.
They maintain that the thigh bone, bent like an ape, was intentionally left unchecked, as this would have discredited the theory that he was walking on two feet.
Scroll down for video
French paleontologist Michel Brunet discovered remains belonging to Sahelanthropus tchadensis in northern Chad in 2001. Brunet maintains the creature, nicknamed “Toumai”, walked on two legs over 6 million years ago and is the oldest ancestor known to mankind
French paleontologist Michel Brunet first discovered the remains of a Sahelanthropus in the Djurab desert in northern Chad in 2001.
Brunet, a researcher at the University of Poitiers in France, nicknamed the specimen “Toumai” and, in a 2002 Nature report, argued that it was bipedal.
His main proof was that the base of his skull would have connected to a vertical spine.
Using radiometric dating, his team determined that Toumai was between 6.8 and 7.2 million years old and lived at some point during the Miocene era.
Brunet maintains that the base of Tumai’s skull shows that he would have rested on an erect spine. But doubts about whether Sahelanthropus was bipedal only increased with the release of a new report suggesting the creature’s femur shows it crawled on all fours, like a monkey.
This makes Toumai more than twice as old as the oldest known ancestor to mankind, “Lucy”, discovered in Ethiopia in 1974 and dating to around 3.2 million years ago.
A left femur and two forearm bones have also been discovered, but for some reason Brunet has never published anything about them and few other researchers have had access to the bones.
In 2004, Aude Bergeret-Medina, a researcher in Poitiers, identified an unmarked bone as a femur – most likely, she theorized, to be a primate.
Eventually, she and her mentor, paleoanthropologist Roberto Macchiarelli, came to believe that they had fallen on Toumai’s thigh bone.
Aude Bergeret-Medina, researcher in Poitiers, identified an unmarked bone like Tumai’s femur. The thigh bone is not straight but curved, which, according to Bergeret-Medina, is more typical of a monkey
But after Bergeret-Medina took measurements and photographs, the bone disappeared and none of the scientists saw it again.
When Brunet’s team didn’t publish anything about the femur, she and Macchiarelli used his notes and prepared their own report.
They attempted to present their findings at a conference organized by the Paris Anthropology Society, but were rejected.
Their hypothesis that Toumai was not standing was ultimately published in the December 2020 edition of the Journal of Human Evolution.
The photos of the femur were reviewed by Bergeret-Medina and his mentor, Roberto Macchiarelli. Macchiarelli claims Brunet blocked access to the actual femur because it would discredit the theory that Toumai walked on two legs
According to the report, the femur is not straight but curved, which is more typical of a monkey.
Others doubted that Toumai was a human ancestor before.
Shortly after the publication of Brunet’s first results, Milford Wolpoff, professor of anthropology at the University of Michigan, questioned them.
“Toumai may be a common ancestor of apes and humans, but he’s not on the line leading directly to humans,” Wolpoff wrote in a letter to Nature. “We think Toumai is an ape and we think it’s probably a female because of his canines.
The teeth were small, he said, but they could still easily belong to a female gorilla or a chimpanzee.
Wolpoff also pointed to scars on his skull left by the muscles of the neck, saying they suggested that Toumai was crawling on all fours with his head horizontal on his spine.
A rendering of what Sahelanthropus tchadensis might have looked like when he was alive
Geographer Alain Beauvilain, who helped excavate Toumai, even raised questions about where and when the bones were found – suggesting they were disturbed by locals at some point in the past.
In September, paleontologist Franck Guy, co-author of the original Sahelanthropus article, published a separate study doubling down on the bipedal theory.
He argued that the femur had a hard ridge near the top, which would support a straight body.
But his report was posted on a pre-print server, which means it has yet to be peer reviewed.
Brunet still maintains that his Sahelanthropus is a missing link in the family tree of humanity.
“Toumai’s skull is, in essence, a hominid skull,” he told state-run Chinese news agency Xinhua in 2019. It has a “very small” canine tooth, like a human. “Only the dog can prove that it is not a great ape.
Macchiarelli claims Brunet and his colleagues blocked access to the femur and had his presentation flattened, as this would discredit their theory that Toumai walked on two feet.
But Brunet insists that “there is no controversy”.
“No one can scientifically say that this femur belongs to Toumai.
[ad_2]
Source link