Evidence suggests that Pinnipeds branched off from terrestrial mammals around 50 million years ago. Based on morphological and molecular analysis, scientists believe that the Pinnipeds likely descended from a single ancestral line (rather than multiple lines). The discovery of a fossil known as Puijila darwini in 2007 helped to establish a more complete picture of the evolutionary origins of the seals. Living around 20 to 24 million years ago in freshwater habitation, Puijila resembled a small carnivorous mammal with webbed feet. This fossil offers important insight into the earlier stage of Pinniped evolution. Another fossil known as Enaliarctos more closely resembles modern seals with their marine specialization.