labyrinthodont

Any of various extinct amphibians of the group Labyrinthodontia, which were the dominant animals of the late Paleozoic Era. Labyrinthodonts had stocky, lizardlike bodies with short limbs, and fishlike teeth with labyrinthine structure (with complex infolding of the enamel). They varied from the size of a salamander to that of a crocodile. One early genus, Ichthyostega, was probably the first terrestrial vertebrate.