Redescription of Harmothoe mexicana Chamberlin, (Polychaeta: Polynoidae), a deep-sea scale worm associated with Hexactinellida sponges

Chamberlin in 1919 described the species Harmothoe mexicana from western Mexico. The type material of this benthic species was collected using a small beam trawl operating between 1244 and 1558 m depth, between María Magdalena and Cleofas Islands, and at the entrance of the Gulf of California, off Mazatlán. The species was again recorded in 1972 by Fauchald off Isla Revillagigedo and Panama, at 841 and 585 m depth, respectively. Herein, new records of Harmothoe mexicana are presented from the west coast of the Baja California Peninsula, collected with a benthic sledge at 710–850 m depth, associated with three species of Hexactinellida sponges: Hyalonema cf. tylostylum, Crateromorpha sp. and Caulophacus sp. Syntypes of H. mexicana were examined. A redescription and iconography of the main features of this species are provided. It is suggested that Lagisca pedroensis Hartman, is a subjective synonym of Harmothoe mexicana, but it is necessary to examine the type to corroborate this hypothesis.