Tennessee River and Crawfish Distribution 



,88 > * 



Fig. 1. Distribution of Procambarus {Pennides). Arrow designates route of 

 proposed "Miocene Tennessee River." Diagonal rulings = cephalic process pres- 

 ent; horizontal rulings = cephalic process absent; vertical rulings = P. (Pe.) 

 versutus. 



River drainage (proper) and the upper part of the Pearl River drainage 

 (Fitzpatrick 1977b). Clearly, then, considerable diversity of cambarine 

 crawfishes seems to have originated in a secondary center associated 

 with the lower reaches of the Mississippi River and its environs, 

 markedly distant from the "southeastern" primary center envisioned by 

 Hobbs (loc. cit.). An enigma of how the several populations became 

 established there presents itself. Since this is not a taxonomic paper, it 

 seems improper to continue a discussion of detailed relationships; 

 besides, Hobbs (1967, 1969, 1981, 1984) has explained well our current 

 knowledge of phylogenies. Instead, I propose to examine geographic 

 and geologic information, particularly some recently collected data, 

 which could assist in resolving some of the apparent paradoxes of craw- 

 fish distribution. 



GEOLOGIC CONSIDERATIONS 



Classical thinking by crawfish workers (and many others) estab- 

 lishes a thesis that, during some pre-Pleistocene period, the upper and 

 lower portions of the Tennessee River were separate. Faunal compari- 

 sons certainly seem to indicate this. The upper basin is more intimately 



