Redescription of the fish parasite Nerocila japonica Schioedte & Meinert, 1881 (Crustacea: Isopoda: Cymothoidae), with comments on previous records of N. acuminata in Japanese waters.

Nerocila japonica Schioedte & Meinert, 1881 is redescribed based on the holotype and specimens from various localities in Japanese waters. The following fishes are recorded as new hosts: Tribolodon hakonensis (Cyprinidae), Mugil cephalus, Liza affinis, Chelon haematocheilus (Mugilidae), Lateolabrax japonicus, L. latus (Lateolabracidae), Acanthopagrus latus, A. schlegelii schlegelii (Sparidae), Rhyncopelates oxyrhynchus (Terapontidae), Ditrema viride, D. temminckii temminckii (Embiotocidae), Chaenogobius gulosus, Acanthogobius flavimanus (Gobiidae), Pseudolabrus sp. (Labridae) and Aluterus monoceros (Monacanthidae). Specimens previously recorded as 'Nerocila acuminata' from Toyama Bay (the Sea of Japan) were examined, when available, and re-identified as N. japonica. As there has been no reliable record of N. acuminata Schioedte & Meinert, 1881 from off Japan, reports of this species in Japanese waters are considered to represent N. japonica.