Intertidal Thalassinidean Shrimps (thalassinidea, Callianassidae and Upogebiidae) of the West Coast of Baja California, Mexico: Annotated Checklist, Key for Identification, and Symbionts

An annotated checklist of the intertidal species of Thalassinidea of the west coast of Baja California, Mexico, and an updated comparative list of their commensals and parasites that live inside the burrows of these crustaceans or on their body, is provided. Four species of burrower shrimps, the mud shrimp, Upogebia macginiteorum (Williams, 1986) [Upogebiidae] and the ghost shrimps, Neotrypaea biffari (Holthuis, 1991), N. californiensis (Dana, 1854), and N. gigas (Dana, 1852) [Callianassidae] were collected during our survey. For each species, the diagnostic features, distribution, and some ecological remarks are recorded, which include: (1) a revised diagnoses for the Neotrypaea species; (2) a range extension for N. californiensis and N. gigas from San Quintin Bay, Baja California, Mexico to El Coyote Estuary, near Point Abreojos, Baja California Sur, Mexico; (3) nine new records of symbiotic associations; and (4) the first record for Mexico of the commensal copepod, Clausidium vancouverense (Haddon, 1912). An illustrated key to the identification of the intertidal species of thalassinideans of the Californian Province is included as well.