A rare fossil dating back 10 million years unveils a new vision of human evolution

Rudapithecus is located near an old mining town of central Europe known for its picturesque turquoise blue quarry water. For 10 million years, the fossilized monkey has been waiting in Rudabánya, Hungary, to add its story to the origins of how humans have evolved.

Rudabánya provided a pelvis – one of the most instructive bones of a skeleton, but rarely preserved. An international research team led by Carol Ward of the University of Missouri, analyzed this new basin and discovered that human bipedalism – or the possibility for people to move on two legs – could possibly have more ancestral origins. deeper than expected.

The Rudapithecus Basin was discovered by David Begun, Professor of Anthropology at the University of Toronto, who invited Ward to collaborate with him to study this fossil. Begun's work on limb bones, jaws and teeth showed that Rudapithecus was a relative of monkeys and humans of modern Africa, a surprise considering its location in Europe. But the information on his posture and his locomotion being limited, the discovery of a basin is important.

"Rudapithecus looked like a monkey and probably moved between the branches, as the monkeys do now: he's holding his body upright and climbing on his arms," ​​said Ward, professor emeritus of pathology and anatomical sciences at the Faculty of Medicine of the MU the study. "However, he would have deferred from his lower back, which would mean that when Rudapithecus fell to the ground, he might have had the ability to stand up straighter than humans." This evidence supports the idea that rather to ask why the human ancestors got up on all fours, maybe we should ask ourselves why our ancestors never fell on all fours. "

Modern African monkeys have a long pelvis and lower back because they are very large animals, which is one of the reasons they usually walk on all fours when they are at home. ground. Men have the lower back longer and more flexible, which allows them to stand up and walk effectively on two legs, characteristic of human evolution. Ward said that if humans had evolved from an African monkey-shaped body, substantial changes to lengthen the lower back and shorten the pelvis would have been necessary. If humans had evolved from an ancestor closer to Rudapithecus, this transition would have been much simpler.

"We were able to determine that the Rudapithecus would have had a more flexible torso than the current African great apes because it was much smaller – about the size of a medium sized dog," Ward said. "This is significant because our finding goes in the direction of the idea suggested by other evidence that human ancestors may not have been built quite like modern African monkeys."

Ward is associated with Begun to study the basin with Ashley Hammond, assistant curator of biological anthropology at the American Museum of Natural History, and J. Michael Plavcan, professor of anthropology at the University of Arkansas. The fossil is not 100% complete, the team used new 3D modeling techniques to complement its shape numerically, and then compared its models to those of modern animals. Ward said their next step will be to perform a 3D analysis of other fossilized body parts of Rudapithecus in order to paint a more complete picture of his movement, giving a better overview of the ancestors of African monkeys and humans.