Mud shrimps of the genus Callianassa leach from the Brazilian coast (Crustacea, Decapoda)

Callianassa branneri Rathbun was the only species of the genus recorded from the Atlantic coast of South America. In the present work five other species are recorded. Callianassa guassutinga, C. guara and C. mirim are considered as new to science. Callianassa major Say, 1818 and C. jamaicensis Schmitt, 1935, were previously known from the Atlantic coast of North America. The variety louisianensis of Callianassa jamaicensis is considered without systematic value as the present material fills most gaps between the variety and the typical form. All the species here described (or redescribed) fit perfectly in the subgenus Callichirus, besides having the same branchial formula and number of pleopods, characteristics also considered as significant to their taxonomy.