Acanthurus albimento, a new species of surgeonfish (Acanthuriformes: Acanthuridae) from northeastern Luzon, Philippines, with comments on zoogeography

Acanthurus albimento is described as a new surgeonfish from northeastern Luzon from six specimens collected during extensive fish-market surveys in the Philippines. The new species is characterized by a distinctive white band below the lower jaw; many irregular, wavy, thin, blue lines on the head; a brown-orange pectoral fin with a bluish tinge on the outer membrane of the rays and a dark band on the posterior margin; a narrow rust-orange stripe along the base of the dorsal fin; and a large blackish caudal spine and sheath with the socket broadly edged in black. An analysis using the mitochondrial cytochrome c oxidase subunit 1 (COI), supported by an independent multi-locus analysis, suggests phylogenetic affinities with an Acanthurus clade that includes A. auranticavus, A. bariene, A. blochii, A. dussumieri, A. gahhm, A. leucocheilus, A. maculiceps, A. mata, A. nigricauda, and A. xanthopterus; a clade that shares a suite of color characteristics. Based on the sampling history in the region, the new species may be a limited-range endemic in the westernmost Pacific Ocean, which is unusual for members of this genus. This raises potential questions about drivers of dispersal and long-held assumptions about zoogeographic patterns along the Kuroshio Current.