<i>Naricolax zafirae</i> sp. nov. (Copepoda: Bomolochidae) parasitic in the nasal cavities of <i>Polydactylus oligodon</i> (Polynemidae) from the Western Atlantic Ocean

Abstract The cyclopoid family Bomolochidae Claus, 1875 is one of the most common groups of parasitic copepods infesting fishes worldwide. During a survey of marine fishes from northeast Brazil, a new species of Naricolax Ho, Do &amp; Kasahara, 1983 was found in the nasal cavities of the littlescale threadfin Polydactylus oligodon (Günther, 1860) (Polynemidae) in the Maranhão Gulf, Brazil. Naricolax zafirae sp. nov. can be distinguished from all congeners because it has a pair of acutely pointed tines in the rostral area and an elongated last endopodal segment of leg 4, features that have never been reported in the genus. In addition, the new species differs from the closely related congeners by having a T-shaped rostral area, an outer spine on the second endopodal segment of leg 3 shorter than the segment, and by the apical seta on the last endopodal segment of leg 4 shorter than the rami. The present study provides the first report of a bomolochid parasitizing a fish of the family Polynemidae Rafinesque, 1815 as well as the first report of the genus Naricolax in the Atlantic Ocean. A dichotomous key for species of Naricolax is provided.