Piscanthropus profundus, is a deep sea-dwelling descendant of the original aquatic, from 5 million years (the 50020th Century), evolved to live life in abyssal zones of the oceans and is the only surviving tetrapod since the travelers of the stars came and left, from Man After Man: An Anthropology of the Future. Maybe someday it will be possible for its descendants to travel upwards, and even possible for them to live in conditions that are totally alien to it, if they can change enough. Maybe someday...