Merriam-Webster Collegiate Dictionary - labyrinthodont

 noun  Etymology: New Latin Labyrinthodontia, from Greek labyrinthos + odont-, odous tooth — more at tooth  Date: circa 1852 any of a superorder (Labyrinthodontia) of extinct amphibians of the late Paleozoic and early Mesozoic typically having bodies resembling salamanders or crocodiles and considered to be the earliest tetrapod vertebrates  • ~ adjective