Caves and their Faunas in Florida and South Georgia 63 



■ATTIGUUS 



•i ^'^<''' ■ ^ 

 TROGLOCAMBARUS, ,^ N^. 'r'^CDELICATUS 



^TROGLOCAMBARUS 

 sp. 



Fig. 7. Distribution of Procambarus attiguus, Procambarus delicatus, 

 Troglocambarus sp., and Troglocambarus maclanei. Arrow shows the 

 suggested direction for the dispersal of Troglocambarus lineage. 



groups of crayfishes. The recent discoveries of two troglobitic members 

 of the Seminole Group {Procambarus attiguus and P. delicatus) and an 

 unstudied population of Troglocambarus in the St. Johns River basin 

 (Fig. 7) allows for further speculation concerning the evolution of this 

 lineage. We propose that the initial differentiation of Troglocambarus 

 from ancestral Procambarus stocks occurred in karsts associated with 

 the St. Johns River. Then, one branch of Troglocambarus dispersed 

 from the St. Johns River karst area, via subterranean routes, into cave 

 systems on the western slope of the Northern Highland (Fig. 7). They 

 probably arrived on the western slope already preadapted for co- 

 existence with larger, less specialized cave Procambarus (lineages 4 

 and 5). Unfortunately, the absence of Form I males for the Orlando 



