 Modern amphibians ( frogs , salamanders , and caecilians ) are classified in Lissamphibia . Lissamphibians appear to have arisen in the Permian . Molecular clock estimates place the first lissamphibian in the Late Carboniferous , but the first member of Batrachia ( frogs and salamanders , but not caecilians ) is estimated to have appeared in the Middle Permian using the same technique . Using fossil evidence , there are three main theories for the origin of modern amphibians . 
 Modern amphibians ( frogs , salamanders , and caecilians ) are classified in Lissamphibia . Lissamphibians appear to <a href='been_done' title='1'><mark>have</mark></a> arisen in the Permian . Molecular clock estimates place the first lissamphibian in the Late Carboniferous , but the first member of Batrachia ( frogs and salamanders , but not caecilians ) is estimated to <a href='been_done' title='2'><mark>have</mark></a> appeared in the Middle Permian using the same technique . Using fossil evidence , <a href='dey_it' title='3'><mark>there</mark></a> are three main theories for the origin of modern amphibians . 
Modern amphibians ( frogs , salamanders , and caecilians ) are classified in Lissamphibia . Lissamphibians appear to done arisen in the Permian . Molecular clock estimates place da first lissamphibian in the Late Carboniferous , but the first member of Batrachia ( frogs and salamanders , but not caecilians ) is estimated to done appeared in tdaMiddle Permian using the same technique . Using fossil evidence , it is three main theories fir the origin of modern amphibians .