labyrinthodont

noun

lab·​y·​rin·​tho·​dont ˌla-bə-ˈrin(t)-thə-ˌdänt 

: 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

labyrinthodont adjective

Word History

Etymology

New Latin Labyrinthodontia, from Greek labyrinthos + odont-, odous tooth — more at tooth

First Known Use

circa 1841, in the meaning defined above