Halichoeres gurrobyi, a new labrid fish (Teleostei: Labridae) from Mauritius in the southwestern Indian Ocean, with a review of the H. zeylonicus species complex

The new labrid fish species, Halichoeres gurrobyi n. sp., is described from specimens collected in Mauritius, in the southwestern Indian Ocean. The new species is part of the yellow-striped initial-phase species complex of Halichoeres, comprising several species found in the Indo-Pacific, including the type species for the genus Halichoeres Rüppell. Two of the closest relatives of H. gurrobyi also occur in Mauritius, i.e. H. zeylonicus (the southwestern Indian Ocean [SWIO] genovariant) and the rare deep-reef H. pelicieri. The initial-phases of these species are similar and have been confused, but DNA barcoding clearly shows three distinct DNA lineages in the SWIO and helps resolve the diagnostic characters. The terminal-phase (TP) male of the new species is unknown. The new species is 9% divergent in the sequence of the mtDNA barcode marker COI (minimum interspecific divergence, pairwise; 9.6% K2P distance) from its nearest relative, H. pelicieri. A neighbor-joining tree of COI mtDNA sequences is presented for the species complex