amphibian

Also called batracians, amphibians form a class of tetrapod vertebrates. They are considered to be the oldest land vertebrates having separated from fish some 360 million years ago. The class of modern amphibians includes three orders, urodela (salamanders and newts), anura (toads and frogs) and gymnophiona (amphibians resembling worms). As their name suggests, (amphi, on both sides; bios, life), at least in our regions, they live just as well in either an aquatic or land environment.