2020 Volume 49 Pages 203-219
Two species of bopyroid isopods are first reported on crabs collected from rocky beaches of Yoron Island, middle part of Ryukyu Islands, Japan. A bopyrid, Kepon grapsi (Nobili, 1905) nov. comb., is recorded based on both sexes obtained from the branchial chambers of Grapsus tenuicrustatus (Herbst) (Grapsidae); the genus Lobocepon Nobili, 1905 is synonymized with Kepon Duvernoy, 1840. The finding of K. grapsi nov. comb. in the present study represents the first record from Japan. An entoniscid, Allocancrion yunnu gen. et sp. nov., is described on the basis of the adult females, males, and epircaridium larvae from visceral cavities of Plagusia squamosa (Herbst) (Plagusiidae). Allocancrion gen. nov. is similar to Cancrion but it is differentiated from it by the male lacking pereopod 6 and the epicaridium larva with a very short, unmodified, pereopod 6.