A New Species of Freshwater Bopyrid, Probopyrus iriomotensis (Crustacea: Isopoda), Parasitizing Macrobrachium spp. (Crustacea: Decapoda), from Iriomote Island, Ryukyu Islands, Southwestern Japan

Abstract

A new species of bopyrid isopod, ProbQm,rus iriomotensts sp. nov, para- sitizing pataemonid freshwater shrimps of the genus Macrobrachium, is de- scribed based on material from Iriomote Island, Ryukyu Islands, southwestern Japan, The new species mest commonly infects the branchial chambers of Mticrobrachium shokitai Itujino and Baba, 1973, but rarely also A4L for- mosense (Bate, 1868). The new species is siniilar to ProbQgrvrus ascendens (Semper, 1880), R gangetictts Chopra, 1923, and P. giardi Weber, 1892, but can be distinguished from them by a combination of characters of the pleomere and pleotelson, relative body width, and the degree of defiection of the body axis. This is the first species of Bopyridae to be recorded from a freshwater environment in Japan. In addition, the generic assignment of two marine species of Probqpyrus is questioned, and the date of authorship of P, marinLts Nierstrasz and Brender a Brandis, 1923 is clarified,