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 Orcula Complex Three species are included in the Orcula Complex: H. orcula , H. pantanalensis , and H. unita . These are very small to small species (ca. 1.16–1.36 mm ), which have a pronotum with or without a macula, lack a pronotal scintilla, and have small plaques ( Figs. 84–85 , 90 ). The species are grouped here on the basis of the male genitalia, which have a similar general basic shape, especially in lateral aspect, and have the basal ring with a long upper extension ( Figs. 88–89 , 93 ). The currently known species are from the Pantanal region of southern Brazil ( H. pantanalensis and H. unita ), and from Brazil , slightly east of the other species ( H. orcula ).