Sexual Variability of Histological Skin Parameters of Salamandrella keyserlingii (Amphibia, Caudata) in the Aquatic and Terrestrial Phases of its Seasonal Cycle

Histological features of the dorsal (DS), throat (TS) and tail skins (caudal skin, CS) were examined in Salamandrella keyserlingii females of the aquatic and terrestrial morphotypes. Using histological and statistical methods, sexual differences in the relative areas of epidermis, strata compactum and spongiosum, connective tissue in the whole, granular and mucous glands were measured. In the aquatic phase, males, in comparison with females, have larger areas of the connective tissue in TS and DS, a larger area of the epidermis in CS, but smaller areas of the granular glands in the upper part of CS and elements of the connective tissue in the lower part of CS. In the terrestrial phase, sexual differences were weakly expressed. Females, in comparison with males, have larger areas of the connective tissue in the whole and its stratum spongiosum in the upper part of CS. Elements of the connective tissue made the greatest contribution to the formation of sexual differences of the skin in S. keyselingii.