Redescriptions of Nereis oligohalina (Rioja, 1946) and N. garwoodi González-Escalante & Salazar-Vallejo, 2003 and description of N. confusa sp. n. (Annelida, Nereididae)

Type material of several polychaete species described by Enrique Rioja from Mexican coasts are lost, and the current status of some species is doubtful. Nereis oligohalina (Rioja, 1946) was described from the Gulf of Mexico, but it has been considered a junior synonym of N. occidentalis Hartman, 1945, or regarded as a distinct species with an amphiamerican distribution. On the other hand, N. garwoodi González-Escalante & Salazar-Vallejo, 2003, described from Chetumal Bay, Caribbean coasts, could be confused with N. oligohalina. In order to clarify these uncertainties, N. oligohalina is redescribed based on specimens from the Mexican Gulf of Mexico, including a proposed neotype; further, N. garwoodi is redescribed including the selection of lectotype and paralectotypes, and N. confusa sp. n. is described with material from the Gulf of California. A key for the identification of similar species and some comments about speciation in nereidid polychaetes are also included