New Crayfish Species 
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two-thirds of the podomere, as opposed to small (often minute) tubercles; 
(8) fewer but much more highly developed tubercles on the ventromesial 
ridge of the merus; (9) the presence of 3 or more, usually spiniform 
and sometimes bifurcate, tubercles on the ventromesial ridge of the 
ischium; and (10) the occasional presence of multiple cervical spines 
(and small, spiniform hepatic tubercles). 
A few of the characters exhibited by O. carolinensis could be 
interpreted as plesiomorphies within the subgenus. These include multiple 
cervical spines and spiniform hepatic tubercles in some specimens, 
a generally more spinose mien, a short, broad areola, and a color 
pattern that includes a “saddle” on the carapace. It is tempting to 
conclude that it is one of the phylogenetically older species within 
the Spinosus Group and perhaps within the subgenus. On the other 
hand, the various spines and spiniform tubercles could also represent 
periodic recurrences of atavisms. Until such time as the other members 
of the Spinosus Group, especially O. spinosus and O. putnami, have 
been described and defined more thoroughly, any conclusions as to 
the relative “age” of O. carolinensis would be premature. 
Remarks — Fitzpatrick (1987:69) hypothesized that the progenitors 
of Procericambarus occupied the southern extremities of the eastern 
part of the Tennessee River, and that their establishment there “may 
have taken place in early Quaternary times.” From this center they 
spread over the Cumberland Plateau, entered the Ohio system, and 
expanded west. Today the subgenus occupies a broad range that extends 
from the Blue Ridge into eastern Oklahoma and Kansas, and the disjunct 
O. carolinensis is the only representative inhabiting Atlantic Coast 
drainages. In North Carolina, the easternmost montane populations 
of the Spinosus Group occur in the New and upper Little Tennessee 
river basins (Cooper and Braswell 1995), from approximately 270 to 
480 air km (170 to 300 air mi), respectively, west of the westernmost 
populations of O. carolinensis. It seems reasonable, considering the 
incontrovertible affinities of the species, that it derived from an ancestor 
that was part of an early and aggressive Procericambarus stock that 
was widespread in the pre-glacial Teays River and the upper reaches 
of the Tennessee River. If true, this upland stock could only have 
gained access to the Atlantic versant by means of a breach of the 
Blue Ridge and subsequent capture of some upper Teays headwaters 
by an east-flowing Piedmont stream. Ross (1969:283-290) persuasively 
argued that, in the area under consideration, this probably was accom- 
plished “in early Pleistocene time” by headwaters of the young Roanoke 
River. Subsequent southeastward dispersal of this putative ancestor 
in the Greater Roanoke system would have brought it into waters 
