Lironeca desterroensis sp. nov. (Isopoda, Cymothoidae) is described on the basis of 105 females and three males taken from the gill chambers of the marine fish, Cetengraulis edentulus (Cuvier,1829), obtained near Santa Catarina Island, Brazil. The new species resembles Lironeca redmanni Leach, 1818, in size and general appearance but differs from that species in a number of important respects. In the new species, the pleotelson is larger, the pleonites are laterally produced, the uropods have elongate and slender rami and the larval stage (Pullus II) has a prominent frontal projection.
Brazil; cymothoid; fish parasite; gill parasite; Isopod parasite; marine isopod
