1) Amphibian 
• (a.) Of or pertaining to the Labyrinthodonta. • (n.) One of the Labyrinthodonta.
any member of an extinct order (Labyrinthodontia) or subclass of amphibians that constituted the dominant animals of Late Paleozoic and Triassic ... [4 related articles]
Labyrinthodonts meaning labyrinth tooth because of the complex infolding of their tooth enamel) were the first amphibians. These carnivores were the first vertebrates to live on land (at least during part of their life-cycle). They probably lived near the water so they could return to it to lay eggs. Labyrinthodonts had conical teeth with maze-like...
Lab`y·rin'tho·dont adjective (Paleon.) Of or pertaining to the Labyrinthodonta. -- noun One of the Labyrinthodonta. 
[n] - an amphibian of the superorder Labyrinthodontia
labyrinthodont 1. A genus of very large fossil amphibians, of the Triassic period, having bony plates on the under side of the body. 2. Etymology: literally 'labyrinth-toothed'. It is from the order Labyrinthodonta which is also known as Mastodonsaurus.
noun an amphibian of the superorder Labyrinthodontia