3.6 Million-Year-Old Relative of 'Lucy' Discovered: Early Hominid Skeleton Confirms Human-Like Walking Is Ancient (http://www.sciencedaily.com/releases/2010/06/100621151119.htm)
QuoteScienceDaily (June 21, 2010) â€" Meet "Lucy's" Great-Grandfather. Cleveland Museum of Natural History Curator and Head of Physical Anthropology Dr. Yohnannes Haile-Selassie led an international team that discovered and analyzed a 3.6 million-year-old partial skeleton found in Ethiopia. The early hominid is 400,000 years older than the famous "Lucy" skeleton and is significantly larger in size. Research on the new specimen reveals that advanced human-like, upright walking occurred much earlier in the evolutionary timeline than previously thought...
This ties in with the Ardi skeleton first shown a while ago. It has been the received wisdom that the common ancestor of Chimps and Humans would be more chimp like than human like. In particular with regard to the walking stance of the animal. Ardi challenged this view and this latest discovery looks like it also supports the view that our common ancestor with the chimp walked upright on chimp-like feet. So while our lineage has retained and refined the upright walking stance and has lost the opposable big toe our chimp relatives have actually been losing the ability to walk upright in favour of improved arboreal mobility conferred by the opposable big toe.