Abstract / Introduction / Summary:
Five individuals (four males and one ovigerous female) of the branchiuran argulid Argulus matuii Sikama, 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 examined had six streaks of brilliant yellow fringed with dark brown pigments on the dorsal side of the carapace, which are a distinct feature in the male and female 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 species from five congeners lacking such streaks from Japan (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)
