Two almost complete fossil skeletons of Gerrothorax maritimus were found in Guizhou Province, China, and it has been described as the first known fully marine stem amphibian. It lived about 237 million years ago, in the Late Triassic period of the Mesozoic Era. It was a member of Temnospondyli, a now-extinct group of early tetrapods (four-limbed vertebrates) linked to the amphibian lineage. The species name “maritimus” refers to its marine habitat.
