New records for Synalpheus peruvianus Rathbun, 1910 (Decapoda, Caridea, Alpheidae) in the East Pacific

Abstract

Over 100 species of Synalpheus have been described (Bruce, 1976; Chace, 1988), of which 19 have been recorded from the eastern tropical Pacific (Wicksten & Hendrickx, 2003). These caridean shrimp are typical of a rocky environment in tropical and subtropical coastal ecosystems and are often found associated with corals, sponges, and crinoids (Banner & Banner, 1975; Dardeau, 1984). The eco logical study of the species of Synalpheus is complicated, due to the complexity of their systematics. Morphologically similar species are easily confused, while polytypic and amphi-American species make the matter even more complicated, particularly considering that the species are small-sized and that reliable character istics are difficult to use (see Chace, 1972; Banner & Banner, 1975; Christoffersen, 1979; Dardeau, 1984). A recent review of the material included in the crustacean collections of the Smithsonian Institution, Washington, D.C. (USNM) and in the collections of the Invertebrate Reference Collection in Mazatl?n, Mexico (EMU), indicated that Synalpheus townsendi peruvianus Rathbun, 1910 should be given full-species status, and that S. recessus Abele & Kim, 1989 is a junior objective synonym of S. peruvianus. This synonymy will be presented and sustained in a forthcoming contribution. Material reported here represents a significant extension of the geographic distribution of S. peruvianus to the north, and the first record of this species for Mexico.