First report of marine epizoic diatom, Protoraphis atlantica (Protoraphidaceae) on calanoid copepods along the southeastern Arabian Sea

Marine epizoic diatom, Protoraphis atlantica is reported for the first time in coastal waters off Kasargod and open ocean waters off Kannur along the southeastern Arabian Sea. Diatoms infested exclusively the urosome of calanoid copepods Labidocera sp. and Candacia catula. The taxonomic description, ecological habit, and distribution of Protoraphis are described in the present paper along with microscopical analyses. With the present report from the southeastern Arabian Sea, the geographical distribution of Protoraphis can be extended to Indian waters.