Abstract
Calyptraeotheres camposi sp. nov. is described from the Gulf of California, Mexico. The new species is close to C. granti (Glassell, 1933) and C. pepeluisi Campos & Hernández-Ávila, 2010 from the Mexican Pacific and to C. hernandezi Hernández-Ávila & Campos 2006 from the Western Atlantic. These four species feature a third maxilliped with a 2-segmented endopod palp and the exopod with unsegmented flagellum. Calyptraeotheres camposi sp. nov. differs from C. granti and C. hernandezi by having the eyes visible in dorsal view, the carapace with arcuate anterolateral margins, the dorsal, longitudinal depressions connected with the transversal depression, and the propodus of pereiopod 2 equal or slightly longer than the carpus. From C. pepeluisi it is distinguished by the absence of a transversal depression on the carapace and the longitudinal depressions not connecting, the carpus and propodus of the third maxilliped being sub-trapezoidal and sub-conical, respectively, in lieu of subrectangular, and the inner surface of the fixed finger nude instead of bearing short setae near the cutting edge and ventral margin.