Histological study on the skin structure in two mudskippers, Periophthalmus waltoni and Boleophthalmus dussumieri in relation to their terrestrial life

Microscopic structure of skin in two amphibious mudskipper fish; Boleophthalmus dussumieri Valenciennes, 1837 (B. dussumeri) and Periophthalmus waltoni Koumans, 1941 (P. waltoni) were investigated in relation to their lifestyle. The general structure of skin is the same among the two species. Epidermis in B. dussumeri was thicker significantly than P. waltoni. The dermal bulges were only well developed in the skin of B. dussumeri. Mucous cells were absent in the epidermis of P. waltoni but present in B. dussumeri. Both B. dussumeri and P. waltoni have well-developed swollen middle cells as a shared epidermal feature. The thickness of the middle cell layer of the epidermis in B. dussumeri was significantly greater than in P. waltoni. Capillaries in the dorsal and ventral parts of the body are more closely distributed to the epidermal surface in P. waltoni than in B. dussumeri. The diffusion distance in the dorsal epidermis of P. waltoni was less than that in the ventral epidermis of B. dussumeri. A comparative examination of the skin of mudskipper species suggests that, due to the more terrestrial lifestyle adopted by P. waltoni, the skin contributes more to respiration.