Abstract / Introduction / Summary:
Five individuals (four males and one ovigerous fe- male) of the branchiuran argulid Argulus matuii Sika- ma, 1938 were collected from the body surface of a white trevally, Pseudocaranx dentex (Bloch and Schneider, 1801), in the Northwestern Pacific Ocean off Ohara, Chiba Prefecture, central Japan. After these individuals were frozen for 41 days, they were thawed and examined for their body coloration in order to aid in distinguishing fresh specimens of A. matuii from those of its related species. All the individuals exam- ined had six streaks of brilliant yellow fringed with dark brown pigments on the dorsal side of the cara- pace, which are a distinct feature in the male and fe- male of the species. Thus, it is possible to identify fresh specimens of marine argulid with six brilliant- yellow streaks as A. matuii and to differentiate the spe- cies from five congeners lacking such streaks from Ja- pan (Argulus scutiformis Thiele, 1900; A. caecus C. B. Wilson, 1922; A. onodai Tokioka, 1936; A. kusafugu Yamaguti and Yamasu, 1959; and A. quadristriatus Devaraj and Ameer Hamsa, 1977).