CHAETODONTOPLUS POLIOURUS, A NEW ANGELFISH (PERCIFORMES: POMACANTHIDAE) FROM THE TROPICAL WESTERN PACIFIC

摘要

Chaetodontoplus poliourus is described as a new species of pomacanthid fish from 30 specimens collected in New Britain (type locality), other localities in Papua New Guinea, Solomon Islands, Palau, and islands of Indonesia. It was previously regarded as a colour variant of C. mesoleucus (Bloch) by having a grey caudal fin with a narrow yellow margin instead of a yellow fin, yellow instead of white pelvic fins, and more pale yellow anteriorly on the dorsal fin. The two species coexist at several islands of Indonesia, but only C. mesoleucus ranges northwest to the coast of southeast Asia, the Philippines and the Ryukyu Islands, and only C poliourus is found east of the Indonesian province of West Papua. No external morphometric differences could be detected between the two species, but C. poliourus was found to have two supraneural bones, compared to one for C mesoleucus, modally one fewer pectoral-fin rays, and a higher average number of anal-fin rays. Mitochondrial and nuclear DNA analyses revealed significant differences between the species (6.07% sequence divergence on mtDNA and a 25 base pair indel on nDNA), reinforcing their distinct taxonomic status.