Amphibian’s skeletons are made of bones. They have fewer bones than their fishy ancestors, and over the years, the evolutionary changes in the amphibian family have gone in two directions. The frog family has a broad head, large eye sockets, short spine, no tail, and long hind legs. The caecilian group has skeletons with small tubular skulls, tiny eye sockets, long spines, and no legs at all.
The skeletons of salamanders and newts are adapted for a primitive form of walking. A frog’s skeleton, on the other hand, is specially adapted for leaping and swimming. The backbone is the base of an amphibian’s skeleton, and is made of vertebrae. Ribs still remain underdeveloped. By comparing the skeleton of modern amphibians with the fossils of ancient ones, it is possible to determine the era in which they lived.