Cymothoid isopods parasitic on fishes: current knowledge and future perspectives
Cymothoid isopods (Crustacea: Peracarida) are large ectoparasites of fishes. Mature females and males inhabit the buccal or branchial cavities, or burrow into the abdomen, or attach to the body surface of marine, brackish, and freshwater fishes. The mancae, which are released from the brood pouch of adult females, spend a planktonic period and develop into early juveniles infecting host fishes. Currently, 399 species in 49 genera of the family Cymothoidae have been recorded worldwide, including 46 species known from Japan and its adjacent waters. This paper provides a comprehensive review of cymothoid taxonomy, morphology, parasitology, molecular characteristics (cytochrome c oxidase subunit I gene, 16S rRNA gene, or both), life cycle, and host associations, based mainly on Japanese literature and the own observations. This review aims to make these findings more widely accessible.