A new species of crayfish of the genus Orconectes, subgenus Procericambarus (Decapoda : Cambaridae), endemic to the Neuse and Tar-Pamlico river basins, North Carolina

Orconectes (Procericambarus) carolinensis is a new species in the Spinosus Group, and the only member of its subgenus known from east of the Blue Ridge physiographic province. It is endemic to the Neuse and Tar-Pamlico river basins of North Carolina, where it occurs in the Coastal Plain and the eastern edge of the Piedmont Plateau. It is most closely related to O. (P.) spinosus and O. (P.) putnami, but may be distinguished from these and other members of the Spinosus Group by: the greater length of the terminal elements of the form I male gonopod (first pleopod); the shorter and broader areola; the somewhat longer acumen and rostrum; the occasional presence of multiple cervical spines and small spiniform hepatic tubercles; the smaller size; and various aspects of tuberculation and spination of the palm, dactyl, merus, and ischium of the cheliped. The species is probably derived from an ancestral Procericambarus stock that inhabited the Tennessee and Teays river basins, gained access to the Atlantic versant following a breach of the Blue Ridge by headwaters of the young Roanoke River, and later entered the Greater Pamlico River from the Greater Roanoke by stream captures.