Fossil foot bones found in 2009 in northeast Ethiopia offer evidence that early humans walked in two distinct ways around 3.4 to 3.2 million years ago. The recently discovered toes and long metatarsal bones come from the same area, at the same time, as Lucy’s species, Australopithecus afarensis. While Lucy’s foot was arched and compact, the new bones are from another human species with a grasping big toe and a flexible foot, combined with a facility for walking on two legs. It’s not yet known what species the new bones represent.
The feet of both species imply that they moved in the trees and on the ground. But while Lucy’s compact foot is better suited for walking on the ground, the new foot would have been especially effective in the trees. The latter approach ultimately became extinct in what may have been competition among the bipeds.
The fossil foot discovery was announced by Yohannes Haile-Selassie in the journal Nature on March 29, 2012.