The ancient primate Oreopithecus bambolii lived on an island 9 million years ago in the region that is now western Italy. Oreopithecus left an abundance of remains for paleontologists to uncover, making this species one of the best-represented ancient apes in the fossil record. As such, scientists know a lot about Oreopithecus—or at least they thought they did.
A study published July 23 in the Journal of Human Evolution is uprooting traditional knowledge about the way Oreopithecus walked. According to two anthropologists at the University of Texas at Austin, Gabrielle Russo and Liza Shapiro, Oreopithecus was not habitually bipedal, as scientists have purported for over one hundred years.
Russo and Shapiro analyzed pieces of backbones from humans, apes, sloths, an extinct lemur, and ancient hominids. They measured the lumbar (lower back) vertebrae and the sacrum—the bones that lies in between two hip bones and connects the last vertebrae to the tailbone– from the various species, comparing each to Oreopithecus fossils.
They found that Oreopithecus‘ lumbosacral region was different enough from that of humans and other habitual bipedal primates that they probably wouldn’t have been able to stand upright and walk on two feet. The extinct primate’s spine looked more like that of nonhuman hominoids who use all four limbs to mobilize. Humans can transfer body weight in order to balance on two feet—Oreopithecus‘ skeleton wouldn’t have allowed for that.
Although Oreopithecus’ lumbosacral morphology was inconsistent with that of habitual bipeds, scientists can’t be sure exactly how Oreopithecus moved. Modern apes are known to move bipedally for short tasks– Oreopithecus probably walked on two feet for certain activities as well. But this prehistoric ape’s posture and routine movement was not on two feet.
Read the study in the Journal of Human Evolution.
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