Acanthostega

Science & Technology at Scientific American.com: Getting a Leg Up on Land -- [ EVOLUTION ] -- Recent fossil discoveries cast light on the evolution of four-limbed animals from fish: "Among the first fossil finds to pave the way for our modern conception of tetrapod origins were those of a creature called Acanthostega, which lived about 360 million years ago in what is now eastern Greenland. It was first identified in 1952 by Erik Jarvik of the Swedish Museum of Natural History in Stockholm on the basis of two partial skull roofs. But not until 1987 did my colleagues and I finally find specimens revealing the postcranial skeleton of Acanthostega. "