They do not occur in Australia or south of the Sahara in Africa and are rare in South America. History Salamanders are a very old group that diverged early from the other amphibian stocks. A major subclass of extinct amphibians can be found in the fossil record. Members of these two orders were elongate. Some had limbs, some had reduced limbs, and some had no limbs.
Many scientists suggest that the ancestors of modern salamanders are among the lepospondyls.
The modern, extant orders of the Amphibia are placed in the subclass Lissamphibia. The order Caudata includes all the salamanders. Lissamphibia are classified by characteristics of tooth, skin, and body structure. The most abundant family, containing about 200 known species of salamanders, is the Plethodontidae. Evolved in the Appalachian Mountains of the United Sates, it has many species throughout North America, a group of species that has invaded central america and radiated extensively, and two species in Europe.