A new species of Politolana (Flabellifera: Cirolanidae) from the south Brazilian shelf

A new species of cirolanid isopod has been collected on the inner Brazilian continental shelf, from sandy bottoms at depths of 15 m to 48 m. P. tricarinata n.sp. occurs sympatrically with P. eximia, the only other Politolana species recorded from the south Atlantic. This new species is herein described and figures of all appendages are provided. P. tricarinata can be distinguished from other species of Politolana by the presence of three transverse cuticular ridges, or carinae, on the dorsal surface of the cephalon. Along with this autapomorphy, a combination of characters unique to P. tricarinata is provided in the species diagnosis. A key separating the two known Brazilian species of Politolana is included.