Discovery of the mud shrimp genus Anacalliax de Saint Laurent, 1973 (Decapoda: Callianassidae) in the Brazilian coast

Previously known only from Argentina and Uruguay, Anacalliax argentinensis is herein reported for the first time from Rio de Janeiro, representing the first occurrence of genus Anacalliax in the Brazilian coast and the northernmost record of the species in the Atlantic Ocean. Morphological variations on the third maxilliped and first pereopods are discussed based in our material.