This is a debate that has taken a long time to reach a boiling point. Seven million years after an ape-like creature nicknamed Tumai crossed the modern landscape Chad, its means of locomotion have caused controversy among fossil experts. Some claim that it is the oldest representative of the human race. Others said it was just an old monkey.
A line that ignites with a paper Naturelast week, prompting scientists to denounce opponents, while others accused opponents of building theories based on “less than five minutes of observation.”
The essence of the argument is straightforward. Could Tumai, which means “hope of life” in Chad’s indigenous Daza language, walk on two legs, suggesting he might actually be the oldest member of the human family? Scientists who discovered fossils believe that this is so.
Others strongly disagree. They say Toumai is a member of an extinct species Sahelanthropus tchadensis – was not bipedal, but moved on all fours like a chimpanzee. Claims of ancient human ancestry are false, they argue, accusing opponents of cherry-picking data.
The controversy rages even for paleontology, a field marked by the bitterness of its disputes over the interpretation of ancient skulls and bones. In this case, the controversy began in 2001 when paleontologists from France and Chad discovered a distorted skull and other bones in the Djurab desert. They concluded that the shape of the skull means that it belongs a creature that walks upright.
One of the team members, Michel Brunet of the University of Poitiers, said at the time: “It’s a great feeling to hold the beginning of the human race in my hands.” This discovery made Brunet a scientific star Franceespecially in Poitiers, which has a street named after him.
However, the interpretation was based on an examination of the skull alone, critics said. The other bones were put aside until they were examined in 2004 by Aude Bergeret-Medina of the University of Poitiers. He recognized the leg bone and concluded that it came from a primate that walked on four legs, not two. Most importantly, he was supported by his boss, Roberto Macchiarelli.
It took Macchiarelli and Bergeret more than a decade to publish their results. Attempts to present their findings at the Paris Anthropological Society were blocked, they said, while Macchiarelli was accused of scientific misconduct by his opponents.
A report of their work eventually concluded that this indicated that Tumai was a four-legged creature and unlikely to be the founder of the human race. “The evidence supporting bipedalism is very, very weak,” says Macchiarelli.
Last month, the skull and bones finders published their responses Nature and said that the study of the bones indicated bipedality, suggesting that it was closer to mankind than to apes. On Twitter, one of the team, Frank Guy, accused Macchiarelli and his colleagues of drawing conclusions based on 5 minutes of observation and a few photographs. “Our paper is a five-year study,” he said.
Other scientists, including Bernard Wood, a professor at George Washington University, have been vocal in rejecting Guy’s claims while supporting the argument that Tumain’s bones resembled a chimpanzee.
Professor Chris Stringer of the Natural History Museum in London was more cautious. “It’s a shame that these controversies are distracting from really important findings,” he said observe. “Given the peculiar and largely unacknowledged circumstances of the discovery – the bones appeared to have been collected by someone and placed on desert sand – we don’t even know if the skull, leg and arm bones belong together as a single individual.
“I would say the jury is still out on whether Toumain is fully fit to walk on two legs.”
