Revision of the genus Parapagurus (Anomura: Paguroidea: Parapaguridae), including redescriptions of the western Atlantic species

As a result of a revision of the genus Parapagurus Smith, three genera are proposed: Parapagurus sensu stricto, Strobopagurus gen. nov., and Sympagurus Smith reinstated. Diagnoses of the three genera are given, and a number of structures are described. A key to aid in the identification of the genera of the family is presented. All taxa heretofore assigned to Parapagurus are reassigned. Four species of Parapagurus and six of Sympagurus occur in the western Atlantic, including a new species, Sympagurus acinops. All western Atlantic species are redescribed. Parapagurus abyssorum (Filhol) is a senior homonym of the eastern Pacific Parapagurus abyssorum Henderson, and a new name, Parapagurus holthuisi, is given to Henderson's taxon. The subspecies of Parapagurus pilosimanus Smith and Sympagurus bicristatus (A. Milne Edwards) are elevated to specific rank. Sympagurus arcuatus A. Milne Edwards & Bouvier, is a junior synonym of Sympagurus gracilis (Henderson). The treatment of each species includes a synonymy, illustrations, comments on symbiotic associations, and a distributional map. Keys to aid in the identification of the western Atlantic species are presented. The morphological variation of the western Atlantic species of Sympagurus is described.