12-million-year-old ape fossils may help explain human bipedalism
Researchers have described a new species of fossil ape dating back 11.6 million years and suggest a new form of locomotion they call “extended limb clambering”. The research is published in the journal Nature.
The research group, led by Madelaine Boehme, a professor at the University of Tubingen, said the ape, Danuvius guggenmosi, had complete limb bones, and were discovered in southern Germany. Having such complete remains allowed them to deduce that this ape species would have been able to hang from branches by its arms.
However, they would also have been able to hold their hind limbs straight, with a foot which could have been put on the ground.
With a broad thorax, long lumbar spine and extended hips and knees, as in bipeds, and elongated and fully extended forelimbs, Danuvius combines the adaptations of bipeds with apes that hang from tree branches. The authors suggest this may provide “a model for the common ancestor of great apes and humans.”
In a commentary on the research, Tracy L. Kivell at the University of Kent said answering the question of how and why apes evolved into walking human beings depends a lot on how they were able to move around beforehand.
“Did it evolve from an ancestor that lived mainly in the trees, or were these ancestors already walking on all fours on the ground and subsequently evolved to stand up and walk on two feet?”
Kivell noted that chimpanzees and gorillas spend most of their time on the ground walking on their knuckles, though they climb into trees for food, protection and to sleep. In contrast, orangutans will walk standing on their hind legs along branches, an echo, some argue, of the ancestors of humans (and all other apes).
The new research, Kivell said, points to an ape which moved in a previously unknown way that could be “the best model yet of what a common ancestor of humans and African apes might have looked like.”