Compare specimens of a lizard and a salamander and be certain that you can tell an amphibian from a reptile. Relation of Class Amphibia to other groups of animals. The amphibia are considered as intermediate between the fishes and the reptiles, but the present day examples of amphibians, which will be studied, are by no means the connecting link between the two groups. The crossopterygian fish of the type represented by the Devonian genus Eusthenopteron was obviously on the direct line of evolution toward the early amphibians. In turn, the reptiles were derived from certain labrinthodont amphibians during the Carboniferous period of earth history.
Salamanders are more abundant in humid eastern North America than any other place in the world.
There are more species in the central New York and Pennsylvania region than all of Great Britain and Europe. They are represented in our region not only by large numbers of individuals but also by a great diversity of forms. One of the largest families of salamanders, the Plethodontidae, is thought to have arisen in the southern Appalachians, and today they are represented in the mountains and valleys of this area by large number of species. Procure a specimen of an adult plethodontid salamander. Make a sketch of the head in anterior view.