Traditionally, amphibians have included all tetrapods that are not amniotes. They are divided into three subclasses, of which two are only known as extinct subclasses: Subclass Labyrinthodontia (diverse Paleozoic and early Mesozoic group) Subclass Lepospondyli (small Paleozoic group) Subclass Lissamphibia (frogs, toads, salamanders, newts, etc.) Of these only the last subclass includes recent species. With the cladistic revolution, this classification has been modified, or changed, and th… (More on Amphibia)