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