Rhabdamia novaluna, a new species of cardinalfish (Perciformes: Apogonidae) from the western Pacific Ocean, with comments on the synonymy of Rhabdamia gracilis

The new cardinalfish Rhabdamia novaluna sp. nov. (Apogonidae) is described on the basis of 79 specimens collected from the western Pacific Ocean. The new species is most similar to the Indo-West Pacific species Rhabdamia gracilis (Bleeker 1856) in having VI-I, 9 dorsal-fin rays, II, 12 anal-fin rays and 13 pectoral-fin rays, and lacking blackish blotches on the opercle and anterior portion of the body. However, the former can be distinguished from R. gracilis by having 26–31 (modally 28–29) developed gill rakers, 27–31 (modally 28) total gill rakers (including rudiments), body depth at second dorsal-fin origin 25.5–33.1% of SL (mean 30.2%) and a subdermal black blotch or spot on the lower caudal peduncle. Three nominal species, Apogonichthys nudus Regan 1905, Apogonichthys mentalis Evermann and Seale 1907 and Rhabdamia clupeiformis Weber 1909, are regarded as junior synonyms of R. gracilis. A key to species of Rhabdamia is provided.