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John E. Cooper and Martha Riser Cooper 
single hydologic unit, the Greater Pamlico River (Lachner and Jenkins 
1971:62). Particularly notable in the Neuse and Tar-Pamlico faunas 
are a number of disjunct endemic species that exhibit closest affinities 
with congeners whose ranges lie well beyond the two North Carolina 
rivers. 
The endemic fish, Noturus ( Rabida ) furiosus Jordan and Meek, 
is widespread in both rivers, as are its more broadly distributed con- 
geners, Noturus { Schilbeodes ) gyrinus (Mitchill) and Noturus 
(, Schilbeodes ) insignis (Richardson). As interpreted by Taylor (1969), 
however, the closest relatives of N. furiosus are Noturus {Rabida) 
munitus Suttkus and Taylor, Noturus {Rabida) placidus Taylor, and 
Noturus {Rabida) stigmosus Taylor, which, along with N. furiosus, 
comprise the “ furiosus group.” Geographically, the nearest of the three 
western relatives of N. furiosus is N. munitus, which occurs in the 
Conasauga River of southeastern Tennessee and in the Pearl, Tombig- 
bee, and Cahaba rivers of Alabama, Louisiana, and Mississippi (see 
Rohde 1980 for distribution maps). 
The large, branchiate salamander, Necturus lewisi (Brimley), is 
also endemic and widespread in the Neuse and Tar-Pamlico rivers 
(Braswell and Ashton 1985). Its closest relative is considered to be 
the sympatric but wider ranging Necturus punctatus (Gibbes) (Ashton 
et al. 1980; Sessions and Wiley 1985), which inhabits the Atlantic 
Coastal Plain from southeastern Virginia to central Georgia. The ranges 
of these two species, although overlapping in the Neuse and Tar- 
Pamlico basins, are broadly disjunct from those of the other Necturus 
species. Necturus maculosus (Rafinesque) is the only other member 
of the genus that occurs in North Carolina, where it appears to be 
limited to the French Broad River basin in the Blue Ridge (Martof 
et al. 1980:50). 
The ranges of several invertebrates exhibit the same phenomenon. 
The unionid mollusk, Elliptio {Canthyria) steinstansana Johnson and 
Clarke, is endemic to the Tar-Pamlico River, but its nearest relatives 
occur in the James River basin to the north and the Altamaha River 
basin to the south. Among the eight species of crayfishes known to 
occur in the Neuse and Tar-Pamlico rivers (Cooper and Ashton 1985:9- 
10) are two endemic species, Procambarus {Ortmannicus) medialis 
Hobbs, and the species of Orconectes described herein. Procambarus 
medialis is most closely related to two other Coastal Plain members 
of the Planirostris Group in North Carolina: Procambarus {Ortmannicus) 
plumimanus Hobbs and Walton, of the Northeast Cape Fear and New 
(White Oak) basins (Cooper and Braswell 1995), and Procambarus 
{Ortmannicus) pearsci (Creaser), of the Cape Fear, Waccamaw, and 
