Direct Development in the Sponge-associated Deep-sea Shrimp Spongicola Japonica (Decapoda: Spongicolidae)

An investigation of reproduction in the shrimp Spongicola japonica, associated with deep-sea sponges, revealed that juvenile shrimps hatch directly from eggs without intermediate planktonic stages. Gross morphology and behavior of the newly hatched juveniles are similar to those of adult shrimps. The intermolt period is relatively long, requiring approximately 70 days from hatching to the first molt, and a further 80 days to the second molt. In larval and juvenile development of the family Spongicolidae, the shallow-water genus Microprosthema has planktonic larvae, while S. japonica shows direct development. The relationship between the direct development in Spongicolaand the distribution of the host sponge is discussed.