A new family, of apseudomorphan Tanaidacea, Sphaeromapseudidae, is discovered and described from the Caribbean Sea. Sphaeromapseudidae is tentatively placed between the Metapseudidae and Tanzanapseudidae. A new genus Sphaeromapseudes and species, S. plumosetosa, associated with intertidal coral rubble, are described.