A new species of Procolobomatus Castro Romero, 1994 (Copepoda: Philichthyidae) endoparasitic in a deepwater longtail red snapper (Actinopterygii: Lutjanidae) off Ishigaki Island, Japan, with records of philichthyid copepods reported from Asian waters.

A new species of the Philichthyidae Vogt, 1877 (Copepoda: Poecilostomatoida), Procolobomatus hoi n. sp., is described based on adult female specimens recovered from the cephalic sensory canals of Etelis coruscans Valenciennes (Actinopterygii: Lutjanidae) caught off Ishigaki Island, the Ryukyu Islands, southern Japan. The new species differs from its congeners by having the following combination of characters: a long medial cephalic lobe about one-third the length of the body; an armature of five spines on the distal exopodal segment of leg 2; one long apical seta on the papillose leg 4; a caudal ramus armed with one medial and four terminal setae (two middle setae are inflated); and spinulose ornamentation covering the body. Procolobomatus hoi n. sp. is the first member of the genus reported from the western Pacific Ocean and from a host of the family Lutjanidae. Previous records of philichthyid copepods from Asian waters are also reported.