In my blog The Tree of Life, published a few months ago, I wrote about the Last Common Ancestor (LCA) of all placental mammals, that it was a shrew-like animal, living about 65 million year ago. Terrestrial, with insects and fruits as food.
Yesterday Yale University has published an interesting update. Our ancestor most probably was not terrestrial, but lived in trees. More a squirrel than a shrew. This conclusion was drawn, based on a study of fossil ankle bones of Purgatorius as our LCA was named.