Chelidoperca pulchella and C. pollux, two new perchlet species (Serranidae) from the northwestern Pacific Ocean

Abstract

Two new perchlet species (Perciformes: Serranidae), Chelidoperca pulchella [3 specimens, 58.8–70.4 mm standard length (SL)] and Chelidoperca pollux (3 specimens, 68.1–72.3 mm SL), are described from Okinawa Island, Ryukyu Islands, Japan and Nha Trang Bay, Vietnam, respectively. Both new species are morphologically similar to Chelidoperca flavimacula Psomadakis, Gon and Htut 2021, described from the northern Andaman Sea, but can be readily distinguished from other congeners by the presence of many yellow spots on the anal fin, and three [2 full-sized and 1 (uppermost) half-sized] scales from the dorsal-fin base mid-point to the lateral line. However, the former differ primarily from C. flavimacula in having fewer yellow spots on the anal fin (2 or 3 spots on each membrane between the 3rd to 6th soft rays in the new species vs. 3 or 4 in C. flavimacula), and a single row of mandibular scales extending anteriorly from the angular onto the ventral surface of the dentary (vs. scales restricted to the angular in C. flavimacula). Chelidoperca pulchella is readily distinguished from C. pollux, the former having interorbital scales extending anteriorly beyond the mid-orbit (vs. ending at the mid-orbit), a deeper body (depth at pelvic-fin origin 25.8–26.4% of SL vs. 23.5–24.1% of SL), longer head (length 39.0–39.4% of SL vs. 35.6–36.3% of SL), larger eyes (orbit diameter 13.5–14.1% of SL vs. 11.0–11.7% of SL), and longer pectoral fins (length 27.8–29.8% of SL vs. 24.7–26.4% of SL). Since mitochondrial COI sequences from the type specimens of C. pulchella closely matched that of a specimen from the Philippines, the species may have a widespread distribution on the upper continental slope from the Ryukyu Islands to the Philippines.