When Did Human-Chimp Lineages Diverge

http://news.bbc.co.uk/2/hi/science/nature/4991470.stm

The US investigation indicates the human and chimp lines split no more than 6.3 million years ago and probably less than 5.4 million years ago.

It is a problematic finding because of our current understanding of early fossils, such as the famous Toumai specimen uncovered in Chad.

Toumai (Sahelanthropus tchadensis) was thought to be right at the foot of the human family tree. It dates to between 6.5 and 7.4 million years ago. In other words, it is older than the point of human-chimp divergence seen in the genetic data.

http://primatology.net/2007/02/24/reassessing-the-time-at-which-human-chimp-lineages-diverged/

http://www.evolutionpages.com/homo_pan_divergence.htm

http://www.pnas.org/cgi/content/full/102/52/18842