Abstract
Recent collecting efforts in the Neotropics have led to the discovery of numerous new species and lineages of aquatic beetles. Here, three new genera are described to accommodate fifteen new species of water scavenger beetles of the subfamily Acidocerinae from northern South America: Crucisternumgen. n. for C. escalerasp. n. (Venezuela), C. ouboterisp. n. (Guyana, French Guiana, Suriname, Venezuela), C. queneyisp. n. (French Guiana), C. sinuatussp. n. (Brazil), C. toboganensissp. n. (Venezuela), C. vanessaesp. n. (Suriname), and C. xingusp. n. (Brazil); Katasophistesgen. n. for K. charynaesp. n. (Peru), K. cuzcosp. n. (Peru), K. meridasp. n. (Venezuela) and K. superficialissp. n. (Ecuador); and Nanosaphesgen. n. for N. castaneussp. n. (Brazil), N. hesperussp. n. (Suriname), N. punctatussp. n. (Guyana), and N. tricolorsp. n. (Guyana, Suriname). It was also found that the monotypic Neotropical endemic genus Dieroxenus Spangler, 1979, syn. n. is congeneric with Chasmogenus Sharp, 1882 resulting in the single new combination Chasmogenus cremnobates (Spangler, 1979), comb. n.. Katasophistes meridasp. n. is known exclusively from seepage habitats, while the remaining taxa described herein are primarily associated with the margins of densely forested streams. Diagnoses, illustrations, distribution maps, and habitat summaries are provided for all new genera and species. A key to the genera of Acidocerinae of the New World is provided.