The Indo-Pacific genus Solenostomus Lacepède, 1803, belonging to the monogeneric family Solenostomidae, includes at least five valid species: Solenostomus cyanopterus Bleeker, 1854, Solenostomus halimeda Orr, Fritzsche and Randall, 2002, Solenostomus leptosoma Tanaka, 1908, Solenostomus paradoxus (Pallas, 1770), and Solenostomus snuffleupagus Short and Harasti, 2026. Among them, S. cyanopterus, S. leptosoma, and S. paradoxus have previously been recorded from Japanese waters. During a taxonomic study of the genus, four specimens (36.7–57.5 mm standard length) of S. halimeda, collected from the Satsunan Islands (Tanega-shima, Takara-jima, and Okinoerabu-jima islands), Kagoshima Prefecture, Japan, were found in the Kagoshima University Museum Ichthyological Collection. The specimens were characterized by the following combination of characters: first dorsal, pelvic, and caudal fins short; caudal fin rounded, truncate; all fin membranes not incised; olfactory rosette sexually dimorphic, females with a small dorsal patch of nasal lamellae, males with a larger patch filling about half of nasal cavity; premaxillary spine absent in both sexes; and dermal papillae multifid. Although S. halimeda has previously been recorded from the Maldives, Western Australia, Papua New Guinea, Indonesia, the Mariana Islands, the Marshall Islands, and Taiwan, it has not been recorded from Japan. Thus, the presently reported specimens represent the first records of S. halimeda from Japanese waters. In addition, the occurrence of the species in waters off Chiba, Shizuoka, Wakayama, and Kochi prefectures, the Okinawa Islands (Okinawa and Zamami islands), and the Miyako Islands (Shimoji-jima Island) was confirmed on the basis of underwater photographs. The new standard Japanese name “Ginga-furaiuo” is proposed, based on the Okinoerabu-jima specimen. A revised key to the species of Solenostomidae is also provided.
