Nippoparasitus unoashicola, a new genus and species of philoblennid copepod (Cyclopoida) parasitic on the Pacific sugar limpet, Patelloida saccharina (Linnaeus, 1758) (Patellogastropoda: Lottiidae) from the intertidal zone of eastern Japan.

Nippoparasitus unoashicola, a new genus and species of mesoparasitic copepod, is described based on specimens of both sexes collected from the mantle cavity of the Pacific sugar limpet, Patelloida saccharina (Linnaeus, 1758) (Patellogastropoda: Lottiidae), in the intertidal zone of the Uraga Channel (North Pacific Ocean), Japan. Nippoparasitus gen. nov. differs from other philoblennid genera by two unique characters: the labium is bloated and branched into multiple digitate lobes in female, and the antenna has three claw-like spines on the terminal segment. Nippoparasitus is probably closely related to Myzotheridion Laubier & Bouchet, 1976 with which it shares a series of processes on the terminal segment of the maxilla.