[Ichthyology • 2016] 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.

Key words: coral-reef fishes, ichthyology, new species, taxonomy, systematics, wrasse, Africa, DNA barcoding.

Diagnosis. Dorsal-fin rays IX,11 (12); anal-fin rays III,11; pectoral-fin rays 13; lateral-line scales 27 (+1 on caudal-fin base), single small pore per scale; suborbital pores 6–7; gill rakers 19–21; a single pair of large, projecting, and slightly recurved canine teeth anteriorly in each jaw, the lowers curving forward and fitting between uppers when mouth closed, second canines about half size of first, followed by rows of mostly caniniform teeth, no canine posteriorly at corner of mouth; elongate body, body depth 4.5–5.0 in SL; body width 1.7–2.3 in depth; caudal fin slightly rounded to truncate in IP; color pattern of IP comprises yellow stripes on a pale background, on holotype three lateral stripes and a fourth along dorsal-fin base, on paratype two midlateral stripes plus dorsalfin base stripe; large black blotch on caudal peduncle and caudal-fin base, saddle-like in paratype and larger specimens; small black spot at upper rim of pectoral-fin base; fins translucent except yellow band along distal dorsal fin and posterior margin of caudal fin. Colors of TP male unknown.

Etymology. Named for Chabiraj (Yam) Gurroby, in recognition of his 35 years of efforts in observing and collecting the fishes of Mauritius. He operates Ornamental Marine World Ltd. with his children Mohesh and Meneeka Gurroby.

Distribution. The new species is described from specimens from Mauritius only.