Revision of the isopod crustacean genusMothocyaCosta, in Hope, 1851 (Cymothoidae: Flabellifera), parasitic on marine fishes

The genus Mothocya is fully revised. Irona Schioedte and Meinert is placed in synonymy with Mothocya. All named species but one, including 18 new species, are described and figured in detail. A further eight undescribed species are listed. With one exception Mothocya species are all gill parasites found principally on atherinomorph fishes of the families Hemiramphidae, Belonidae, and Atherinidae. Brief accounts are given of the biogeography, biology and host-parasite interaction of the species of Mothocya. Keys to the species are provided for the different major biogeographic regions.