New records and description of fifty-four new species of aquatic beetles in the genus Hydraena Kugelann from South America (Coleoptera: Hydraenidae) Author Perkins, Philip D. text Zootaxa 2011 2011-10-28 3074 1 198 journal article 31530 10.5281/zenodo.1050060 2d28bebf-e3c5-457b-9152-8a6877ded281 1175-5326 1050060 Curvosa Group The Curvosa Group comprises three species: H. curvosa ( Brazil , Peru ), H. takutu ( Guyana ) , and H. hintoni ( Brazil ) . These are rather convex species, moderately sized (ca. 1.48–1.76 mm ), with a characteristic habitus ( Figs. 16– 18 ). The coxae are rather widely separated by P1 and especially P2, and the plaques are also widely separated. The genae usually have an ill-defined posterior ridge laterally. The male genitalia are quite stout, and have a basic plan similarity; the parameres are moderately large, and the right paramere has modified setae ( Figs. 15 , 19, 20 ). The female gonocoxite is "divided", having a weakly sclerotized midlongitudinal area, and is similarly shaped in all species in this group (e.g., Fig. 149 ). The spermatheca ( Figs. 151–152 ) is circular, somewhat disc-shaped, markedly differing from that of all American Hydraena , except members of the Paeminosa Group. Externally and male genitalically the two groups are very different. Two of the species in this group, H. curvosa and H. takutu , so far have only been collected from leaf packs taken from streams.