Systematics of the Troglobitic Caecidotea 



(Crustacea: Isopoda: Asellidae) 



of the Southern Interior Low Plateaus 



Julian J. Lewis 



Department of Biology and Water Resources Laboratory, 

 University of Louisville, Louisville, Kentucky 40292 



ABSTRACT. — Caecidotea meisterae is synonymized with Caecidotea 

 whitei, which is reduced to a subspecies of Caecidotea bicrenata. This 

 species is now divided into two subspecies: Caecidotea bicrenata 

 bicrenata and Caecidotea bicrenata whitei. Caecidotea b. bicrenata 

 occurs in caves from northern Alabama to central Tennessee. From 

 northern Tennessee to southern Illinois it is replaced by C. b. whitei. 



Fleming (1972a), following Bresson (1955) and Steeves (1963; 

 1964), considered Caecidotea alabamensis Stafford (1911 to be a wide- 

 spread troglobite inhabiting caves of practically the entire Interior Low 

 Plateaus, from Alabama to Indiana and Illinois. Lewis and Bowman 

 (1981) pointed out the morphological and zooeographical dissimilarities 

 of C. alabamensis to species occurring in caves of the Interior Low Pla- 

 teaus, restricting the known distribution of C. alabamensis to the type- 

 locality, Auburn, Alabama. Caecidotea j or dani (Eberly) was resurrected 

 for a distinct species in central Indiana, as was Caecidotea bicrenata 

 (Steeves) for the troglobitic species in northern Alabama. Three new 

 species closely related to C. jordani and C. bicrenata were described by 

 Lewis and Bowman (1981) to encompass "alabamensis" collections from 

 southern Illinois, Kentucky, and northern Tennessee. These were Caeci- 

 dotea beattyi, Caecidotea meisterae, and Caecidotea whitei. 



Additional information now necessitates modification of oart of the 

 scenario of Lewis and Bowman (1981) for the "alabamensis" species. 

 While that paper was in press, collecting in Mammoth Cave National 

 Park produced both Caecidotea whitei and C meisterae, in addition to 

 Caecidotea stygia. The presence of both C. stygia and C. whitei in the 

 ecologically complex Mammoth Cave System was explained by Lewis 

 and Lewis (1980). However, the presence of three species stretched 

 credence, pointing to the possibility that C. meisterae and C. whitei are 

 conspecific. 



Study of numerous specimens from the base level cave rivers of the 

 Mammoth Cave System revealed intergradations between specimens 

 with the weakly developed gnathopods of C. whitei and those with the 

 more fully differentiated gnathopods of C. meisterae. As the morph- 

 ology of the gnathopods was the primary character used to distinguish 

 these two species, it became apparent that they were identical. 



A gray area left unconsidered by Lewis and Bowman (1981) was 

 central Tennessee, where numerous collections previously called 

 "alabamensis" were assigned neither to C. bicrenata nor any of the new 



Brimleyana No. 8:65-74. December 1982 65 



