Actually, we do have a pretty good idea what the skeleton of this…
Actually, we do have a pretty good idea what the skeleton of this common ancestor looked like - about 13 million years ago, Homininae speciated out from the ancestors of the orangutan. About 10 million years ago, Hominini speciated out from the ancestors of the gorillas. About 7 million years ago, Hominina seperated from the ancestors of the chimpanzees. Sahelanthropus tchadensis is the latest common ancestor, with the earliest known human ancestor post-dating the separation of the human and the chimpanzee lines being Orrorin tugenensis.