New Laetoli Footprints Demonstrate Full Bipedality

A story running in Newsweek and the Washington Post (and other outlets, presumably), details research into the newly discovered fossil footprints at Laetoli dated to 3.6 mya that clearly show a modern human gait.

Two sites in Laetoli, Tanzania, feature footprints of human ancestors who lived about 3.6 million years ago. They were members of the genus Australopithecus. That's the genus of “Lucy,” the 3.2 million-year-old human ancestor whose fossilized bones were discovered in Ethiopia in 1974.

David Raichlen, an evolutionary anthropologist at the University of Arizona, has studied the Laetoli footprints and compared them to footprints made by human volunteers in laboratory settings. He examined footprints of individuals walking normally and also those walking with bent knees and bent hips. (Scientists who study locomotion use the acronym BKBH). The Laetoli footprints more closely match modern human footprints.

“Upright, humanlike bipedal walking goes back 4 to 5 million years,” Raichlen told The Washington Post in advance of a symposium on the evolution of human locomotion, which took place Sunday at the Experimental Biology 2018 conference in San Diego.

This dovetails with the recent findings that Ardipithecus, a hominin dated to around 4.4 mya, likely could travel equally well on the ground or in the trees.  Oddly, the WaPo article doesn't mention this.