 An adult salamander generally resembles a small lizard , having a basal tetrapod body form with a cylindrical trunk , four limbs , and a long tail . Except in the family Salamandridae , the head , body , and tail have a number of vertical depressions in the surface which run from the mid @-@ dorsal region to the ventral area and are known as costal grooves . Their function seems to be to help keep the skin moist by channeling water over the surface of the body . 
