A New Species of the Enigmatic Copepod Genus Lernaeascus (Cyclopoida: Philichthyidae), Parasitic on Angelfishes (Actinopterygii: Pomacanthidae) from the Ryukyu Islands, Japan

抄録

Lernaeascus kabuto sp. nov. (Cyclopoida: Philichthyidae) is described based on specimens of both sexes collected from two species of angelfish (Actinopterygii: Pomacanthidae), the purplemask angelfish Centropyge venusta (Yasuda and Tominaga, 1969) and the yellow angelfish C. heraldi Woods and Schultz, 1953, caught in the East China Sea near Kumejima Island, Japan. Lernaeascus kabuto sp. nov. is easily distinguished from its congener, L. nematoxys Claus, 1886, by the following characters: the male has a pair of elongate, distomedially notched dorsal plates on the second pedigerous somite, four abdominal somites, a pair of dorsal hamuli on the third abdominal somite, a non-bifurcate genital operculum, a curved proximal antennulary segment, a naked maxillule, a maxilla without a posteriorly-directed process on the syncoxa, and the endopod of leg 1 modified into a simple spine; and the female has a triangular antenna, a styliform process on the labrum, and three setae on the exopods of legs 1 and 2.