First specimen-based Japanese record of Oxycheilinus arenatus (Perciformes: Labridae) from the Ryukyu Islands

Abstract

The Indo-Pacific labrid genus Oxycheilinus Gill, 1862 includes 10 valid species, seven having been recorded from Japanese waters on the basis of collected specimens. A single specimen (157.8 mm standard length) of the Speckled Maori Wrasse Oxycheilinus arenatus (Valenciennes, 1840), collected from the Ryukyu Islands, Japan in March 2019, possessed the following characters: a large black basal blotch on the interspinous membranes between the first and fourth dorsal-fin spines; a distinct black longitudinal band from behind the eye to the caudal-fin base; and no black blotch on the body above the pectoral fin. Although widely distributed in the Indo-Pacific, except for the Hawaiian Islands, O. arenatus has been recorded in Japanese waters only from photographs and no Japanese specimens have been found in museum collections. To confirm the collected specimen’s status as the first specimen-based Japanese record of the species, the seven congeners previously recorded from Japan were re-examined. One of these, O. oxyrhynchus was recorded from Japan in 1897 on the basis of two specimens, with no further Japanese specimens reported. Examination of these specimens revealed them to be identical with O. celebicus (also previously recorded from Japan), although a modified illustration (based on original illustration of O. oxyrhynchus) reported as O. oxyrhynchus by subsequent Japanese publications is very similar to O. arenatus in overall body appearance. The Ryukyu specimen represents the first specimen-based record of O. arenatus from Japan. The new standard Japanese name ‘‘Hiiromochinouo’’ is proposed for the species.