A new species of Benthana Budde-Lund, 1908 is described from southern Brazil. Benthana cairensis sp. nov. is distinguished from the other species in the genus by having 17 aesthetascs on the antennula and the elongated male pleopod 1 exopod with a lobe on the inner lateral margin and up to six setae on the outer lateral margin. The new species most resembles B. olfersii (Brandt, 1833), but may be distinguished by lacking the lobe with six setae on the internal margin of the proximal extremity of the merus of pereiopod 7. Furthermore, we include B. olfersii in the subgenus Benthanoscia based on the examined material as described herein.
Neotropical; Oniscidea; terrestrial isopod
