The already famous Tiktaalik, an old species 386 millions of years, was dethroned as the earliest ancestor of land animals. Recently, a trace of an older tetrapod was discovered in a swamp in Poland 9 millions of years. This animal apparently did not have any kind of fins, like fish, but even four legs. At least that's what the coordination of his walk suggests. What is interesting is the environment in which this trace was discovered, like the surrounding invertebrate fossils, suggests that the first tetrapods may have appeared in saltwater lagoons, not in freshwater rivers, as previously believed. This discovery, announced in Nature, seems to be rewriting the history of tetrapods. Here is another possible trace of one missing link. So there are two more…
http://sciencenow.sciencemag.org/cgi/content/full/2010/106/2?etoc
http://www.youtube.com/watch?v=YgGwBm4HI8Q&feature=player_embedded
