Dermal-epidermal relationships in the skin of the bottlenose dolphin (Tursiops truncatus).

Using a variety of methods the outer surface of the dolphin dermis presents as a rather regularly arranged series of mainly longitudinal and approximately parallel ridges which are surmounted by laterally flattened, regularly distributed dermal papillae. At variable intervals groups of dermal ridges are supported by shallow elevations referred to here as basal dermal elevations. These tend to contain vessels and/or nerves for distribution to two or more dermal ridges. The opposing epidermal surface reveals an irregularly edged series of nearly parallel epidermal ridges alternating with the grooves which in the living state contain the dermal ridges. In the depths of these grooves are the crypts which in the intact skin contain the dermal papillae. Nothing is observable which could correspond to the epidermal pegs referred to in the literature. Small irregular epidermal projections (knobs) appear along the free edge of the epidermal ridge. Topographical variations in density and height of dermal ridges, height of basal dermal elevation plus dermal ridge and papillae as well as total epidermal thickness are illustrated by means of skin maps. Inconsistencies in the literature on Cetacean skin are discussed.