Pan prior is the name suggested by British biological anthropologist Richard Wrangham for the last common ancestor of humans (Homo sapiens) and chimpanzees (Pan troglodytes). This species is supposed, on the basis of DNA reconstruction (no fossil remains have been found), to have existed prior to six million years ago, when the human and chimpanzee lines are thought to have diverged. Pan prior lived an arboreal existence in the forests of Africa. It was initially thought that an Ice Age, around seven million years ago, caused forests to shrink thus prompting some members of the species to venture into the savannah, becoming the ancestors of humanity.[4] However, the discovery of Ardipithecus ramidus shows that bipedal locomotion was used both on the ground and in the trees around 4.4 million years ago. Researchers infer from the form of her pelvis and limbs and the presence of her abductable hallux, that she was a Facultative biped: bipedal when moving on the ground, but quadrupedal when moving about in tree branches.
) with us.
