<i>Plectranthias clavatus</i>, a New Perchlet from Japan and Guam, with a Review of the Distributional Records of <i>P. kamii</i> (Perciformes: Serranidae: Anthiadinae)

A new perchlet, Plectranthias clavatus, is described from seven specimens [131.3–199.6 mm standard length (SL)] from Sagami Bay and Hachijo-jima Island, Japan, and Guam. Plectranthias clavatus can be distinguished from all congeners by the following combination of characters: dorsal fin with 10 spines and 17–18 (mode 17) soft rays; pectoral-fin rays 13–14 (13), all branched except for uppermost ray; lateral line complete, with 35–36 (35) pored scales; 5.5 and 16–17 (17) scale rows above and below lateral line respectively; 6–7 (6) diagonal rows of large scales on cheek between orbit and corner of preopercle; body deep, its depth at pelvic-fin origin (BDP) 37.8–40.7 % (mean 39.1 %) of SL, its greatest depth 39.6–42.2 % (41.2 %) of SL; 3rd dorsal-fin spine longest, its length 36.5–45.9 % (41.9 %) of BDP; anal-fin soft rays short, longest ray length 47.9–59.1 % (53.5 %) of BDP; no scales on chin, branchiostegal membranes, infraorbital bones, maxilla, mandibles or snout; predorsal scales extending to posterior two-thirds of interorbital area, anterior margin of squamation not reaching line through posterior nostrils; posterior margin of preopercle serrated, ventral margin with 2 antrorse spines; short flaps at tips of 2nd and 3rd dorsal-fin spines; 3 large orange-red saddles on dorsum; single orange-red stripe on posterior four-fifths laterally, saddles and stripe well-spaced. Distributional records of Plectranthias kamii Randall, 1980, widely reported from the East Indian to Central Pacific Oceans and considered most similar to P. clavatus, were reassessed by reidentification of specimens and photographs accompanying previous records. In Japanese waters, new distribution records for P. kamii were confirmed based on the specimens examined from Cape Omaezaki (Pacific coast of central Honshu), and the Goto Islands, Amakusa Nada Sea and Taka-shima Island (northeastern East China Sea).