STATUS UPDATE FOR BRISTLY CAVE CRAYFISH, CAMBARUS SETOSUS (DECAPODA: CAMBARIDAE), AND RANGE EXTENSION INTO ARKANSAS

This study updates the status, expands the range, and summarizes conservation activities to date for the bristly cave crayfish, Cambarus setosus. A new state record for this crayfish is reported after its discovery at 2 sites in 2 counties (Benton and Independence counties, Arkansas). This makes C. setosus the fifty-eighth crayfish species known from Arkansas. This is also the first record of C. setosus from the Salem Plateau of the Ozark Plateaus ecoregion; it was known previously only from the Springfield Plateau of Missouri. The range of C. setosus in Missouri includes the counties of Barry, Christian, Dade, Greene, Jasper, Lawrence, McDonald, Newton, and Stone; it is not presently known from Oklahoma, as previously reported. Cambarus setosus is probably a species complex with genetic variability at the subspecific level, especially in southwestern Missouri. Cambarus setosus is now known from 50 sites, but only 164 individuals (tallied from the most recent census at each site). This crayfish has been impacted by both habitat degradation and scientific study. Conservation organizations have begun preserving cave entrances, but conservation activity is lacking in subterranean stream recharge zones. Increased protection is recommended, including federal listing under the US Endangered Species Act.