Amphibian, Size range and diversity of structure

The three living groups of amphibians vary greatly in size and structure. Long tails and two pairs of limbs of about equal size distinguish the salamander, although members of the family Sirenidae have no hindlimbs. Their total length varies greatly; a diminutive terrestrial species in Mexico measures 27 millimetres (1.06 inches) long, and the giant aquatic salamander