Status of Exosphaeroma amplicauda (Stimpson, 1857), E. aphrodita (Boone, 1923) and description of three new species (Crustacea, Isopoda, Sphaeromatidae) from the north-eastern Pacific

Exosphaeromaamplicauda (Stimpson, 1857) from the west coast of North America is reviewed and redescribed and revealed to be a group of closely related species. A neotype is designated and the species redescribed based on the neotype and topotypic specimens. Exosphaeromaamplicauda is known only from the coast of California, at Marin, Sonoma and San Mateo Counties. Exosphaeromaaphrodita (Boone, 1923), type locality La Jolla, California and previously considered nomen dubium is taken out of synonymy and re-validated. A further three species: Exosphaeromapaydenae sp. n., Exosphaeromarussellhansoni sp. n., and Exosphaeromapentcheffi sp. n. are described herein. Sphaeromaoctonctum Richardson, 1899 is placed into junior synonymy with Exosphaeromaamplicauda. A key to the Pacific West Coast Exosphaeroma is provided.