A single female specimen (256.4 mm standard length) of Acanthopagrus taiwanensis Iwatsuki and Carpenter, 2006, collected off Kasasa, Minami-satsuma, Kagoshima Prefecture, Japan, was characterized by the following combination of characters: 3½ scale rows between fifth dorsal-fin spine base and lateral line; 3 or 4 oblique scale rows on cheek; modally 15 total gill rakers; 3 or 4 rows of flattened molars on each side of upper and lower jaws; second anal-fin spine robust, bluntly pointed; ventral edge of infraorbitals above maxilla nearly straight; anterior edge of dorsal scaly area of head rounded; no black bars on head; a dark streak on each membrane of anal fin; and anal-fin soft rays whitish. The dorsal- head profile of the Japanese specimen was relatively straight, compared with the convex profile in the type specimens of the species. Other characters of the Japanese specimen, however, agreed well with those of A. taiwanensis given in the original description. Acanthopagrus taiwanensis is very similar to A. pacificus Iwatsuki, Kume and Yoshino, 2010, but can be distinguished from the latter by having 3 or 4 oblique scale rows on the cheek (vs. 6 or 7 in the latter), modally 15 total gill rakers (vs. 17), flattened molar teeth on each side of the upper and lower jaws (vs. rounded molariform teeth), a robust, relatively bluntly pointed second anal-fin spine (vs. acutely pointed), and whitish anal-fin soft rays (vs. blackish). Acanthopagrus taiwanensis has been previously recorded only from Taiwan, the Kagoshima specimen representing the first record from Japan and northernmost record for the species. The new standard Japanese name “Iwatsukikurodai” is proposed for the species and distributional implications of A. taiwanensis in Japanese waters discussed.
