A new species of mud shrimp, Upogebia cortesi, from Pacific Costa Rica (Decapoda : Thalassinidea : Upogebiidae)

Upogebia cortesi, a new species of mud shrimp from the Pacific side of Cost a Rica is described and illustrated. The type series was dredged parallel t o shore in water of 30-40 m depth. The species shares lack of a strong prox imal mesioventral spine on the merus of the second pereopod with several me mbers of the genus from the western hemisphere; moreover, the species stand s alone in having spineless articles on pereopods 1-5 except for fingers of the chelae. The rostrum has no ventral spines. Similarities between this a nd related species are emphasized in a partial abridgment of the key to upo gebiid species in the eastern Pacific.