Discovery of foot fossil confirms two human ancestor species co-existed
|The Burtele partial foot (BRT-VP-2/73). A laboratory photo after cleaning and preparation. It is shown here in its anatomically articulated form [Credit: © The Cleveland Museum of Natural History/Yohannes Haile-Selassie]|
The partial foot was found in February 2009 in an area locally known as Burtele. "The Burtele partial foot clearly shows that at 3.4 million years ago, Lucy's species, which walked upright on two legs, was not the only hominin species living in this region of Ethiopia," said lead author and project leader Dr. Yohannes Haile-Selassie, curator of physical anthropology at The Cleveland Museum of Natural History. "Her species co-existed with close relatives who were more adept at climbing trees, like 'Ardi's' species, Ardipithecus ramidus, which lived 4.4 million years ago."
|The first element of the Burtele partial foot, fourth metatarsal, as it was found on the ground in the Woranso-Mille area of the Afar region of Ethiopia [Credit: © The Cleveland Museum of Natural History/Yohannes Haile-Selassie]|
"This discovery was quite shocking," said co-author and project co-leader Dr. Bruce Latimer of Case Western Reserve University. "These fossil elements represent bones we've never seen before. While the grasping big toe could move from side to side, there was no expansion on top of the joint that would allow for expanded range of movement required for pushing off the ground for upright walking. This individual would have likely had a somewhat awkward gait when on the ground."
|The fourth metatarsal of the Burtele partial foot right after discovery in Stephanie Melillo's hand [Credit: © The Cleveland Museum of Natural History/Yohannes Haile-Selassie]|
"Nearby fossils of fish, crocodiles and turtles, and physical and chemical characteristics of sediments show the environment was a mosaic of river and delta channels adjacent to an open woodland of trees and bushes," said Saylor. "This fits with the fossil, which strongly indicates a hominin adapted to living in trees, at the same time 'Lucy' was living on land."
Source: Cleveland Museum of Natural History [March 28, 2012]