Ontogeny of Osmoregulatory Structures in the Shrimp Penaeus japonicus (Crustacea, Decapoda).

The ontogeny of differentiated osmoregulatory epithelia in the branchial chamber (gills, branchiostegite, pleura, epipodite) was studied by transmission electron microscopy throughout the postembryonic development of Penaeus japonicus. These epithelia are characterized by typical cytological features, including apical microvilli and numerous basal infoldings associated with mitochondria. Differentiated osmoregulatory structures are not observed in the early larval stages: nauplii and zoea 1.