Additional Records of Acanthaxius Caespitosus (Squires, 1979) (Decapoda, Thalassinoidea, Axiidae) from the Eastern Tropical Pacific

Abstract

The mud lobsters of the family Axiidae are represented in the eastern tropical Pacific by seven species. Only one of these species belongs to the genus Acan thaxius Sakai & De Saint Laurent, 1989 (cf. Hendrickx, 1995a), although a second species, A. spinulicauda (Rathbun, 1902) is known from British Columbia and Cal ifornia. Originally described from the Pacific coast off Colombia in the genus Ax iopsis Borradaile, 1903, Acanthaxius caespitosus (Squires, 1979) was transferred to the genus Acanthaxius by Sakai & De Saint Laurent (1989). Acanthaxius caespi tosus and Axiopsis baronai Squires, 1979, a second species of Axiidae also origi nally described from Pacific Colombia, have both been reported from a much wider geographic area by Hendrickx (1987) on the basis of material mostly collected in shrimp trawls. Acanthaxius caespitosus is currently known from the west coast of the Gulf of California, Mexico, off R?o San Juan del Sur, Colombia (type locality), and off Mancora, Peru, thus leaving a wide gap of approximately 22 degrees of latitude with no records (from the southern Gulf of California to southern Colom bia). A recent search in the crustacean holdings of the Invertebrate Collection at Scripps Institution of Oceanography, La Jolla, California, led to the discovery of yet another small series of unidentified specimens of A. caespitosus from locali ties previously not included in the distribution range of this species. Abbreviations used are: TL, total length; CL, carapace length; coll., collector; SIO-C, Scripps Institution of Oceanography Crustacea collection.