Resumen

The Neotropical species of the water scavenger beetle genus Notionotus Spangler, 1972 are revised using an integrative taxonomic approach combining morphology with DNA sequence data from two genes. Support exists for four putative species groups into which 18 species are placed, including twelve that are described here as new: N.bicolorsp. nov. (Suriname), N.bifidussp. nov. (Venezuela), N.brunbadiussp. nov. (Brazil), N.garciaesp. nov. (Brazil), N.giraldoisp. nov. (Brazil), N.insignitussp. nov. (Venezuela), N.jumasp. nov. (Brazil), N.parvussp. nov. (Suriname), N.patamonasp. nov. (Guyana), N.peruensissp. nov. (Peru), N.retusussp. nov. (Guyana), and N.vatiussp. nov. (Brazil). Four new synonymies are created: N.shorti Queney syn. nov. is found to be conspecific with N.dilucidus Queney; N.edibethae García syn. nov., N.nucleus Perkins syn. nov., and N.perijanus García syn. nov. are found to be conspecific with N.tricarinatus Perkins. New records are provided for all previously described species except N.mexicanus Perkins. Within the Neotropical region, the range of the genus is greatly expanded and now known from as far south as Bolivia and the Brazilian state of Mato Grosso do Sul. While a few species are found in hygropetric habitats, most are associated with the margins of forested streams. Genitalia and habitus images are provided for nearly all species, as well as a key to the four species groups.