Prehistoric amphibians are various amphibians that lived before recorded history. The earliest forms date back to at least 350 million years (Carboniferous period). Originally, ancestors were fish-like with fins that looked like legs. Eventually these fins turned into functional legs and they made the transition to land living animals. * ?Balanerpeton * ?Dendrepeton Subclass Labyrinthodontia (paraphyletic) Subclass Lepospondyli * Diplocaulus * Keraterpeton * Microbrachis * Ophiderpeton * Pantylus * Phlegethontia Subclass Lissamphibia (includes recent amphibians as well)