Western Atlantic Shrimps of the Genus Penaeus

Four subgenera of the genus Penaeus are described (Litopenaeus, Penaeus s.s., Fenneropenaeus, and Melicertus). Eight species and subspecies (P. setiferus, P. schmitti, P. duorarum notialis, P. aztecus aztecus, P. aztecus subtilis, P. paulensis, and P. brasiliensis) are recognized as occurring in the western Atlantic. Synonymies are given. Lectotypes have been designated for two species, and the disposition of all types is shown. Diagnoses, detailed descriptions, and illustrations are presented for each species and subspecies. Geographic and bathymetric distributions are given. Affinities are discussed, and conclusions concerning ranges of variation and their spatial distributions are based on morphometric studies and other characters. The development of the external genitalia through the juvenile stage and the size range at which each taxon reaches the subadult stage are presented. Many details of ecology and life history are critically summarized and reviewed. A brief appraisal of the commercial importance of each form is also given.