What's the "een" in Halloween?
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.
a type of tooth made up of infolded enamel that provides a grooved and strongly reinforced structure. This tooth type was common in the true amphibians of the Paleozoic Era, some lobe-finned fishes closely related to tetrapods, and in the early anthracosaurs-which were tetrapods closely related to the amniotes.