Ultrastructure of epidermis of Salamandra salamandra followed throughout ontogenesis.

Ventral epidermal ultrastructure of the amphibian urodele Salamandra salamandra is described and followed throughout its life cycle. Tadpoles were divided into five categories on the basis of the organization of their epidermis and the ultrastructure of its cells. In newly hatched tadpoles the epidermis is arranged in two layers and four types of cells were recognized. The number of epidermal layers increases in the metamorphosing tadpole. At this stage the layers become organized in four strata. Metamorphosis involves the disappearance of some cell types and the appearance of others, typical of the adult epidermis. The significance of these ontogenetic changes in epidermal ultrastructure is discussed in respect to aquatic and terrestrial life habits.