Three additional new genera of acidocerine water scavenger beetles from the Guiana and Brazilian Shield regions of South America (Coleoptera, Hydrophilidae, Acidocerinae).

Recent study of the water scavenger beetle subfamily Acidocerinae in the Neotropical region has uncovered numerous undescribed species that are not able to be placed in existing genera. Here, we describe three new genera to accommodate 17 of these new species from South America: Aulonochares gen. nov. for Aulonochareslingulatus sp. nov. (French Guiana, Suriname), Aulonocharesnovoairensis sp. nov. (Brazil), and Aulonocharestubulus sp. nov. (Brazil, Guyana, Suriname, Venezuela); Ephydrolithus gen. nov. for Ephydrolithushamadae sp. nov. (Brazil), Ephydrolithusminor sp. nov. (Brazil), Ephydrolithusogmos sp. nov. (Brazil), Ephydrolithusspiculatus sp. nov. (Brazil), and Ephydrolithusteli sp. nov. (Brazil); and Primocerus gen. nov. for Primoceruscuspidis sp. nov. (Venezuela), Primocerusgigas sp. nov. (Venezuela), Primocerusneutrum sp. nov. (Guyana, Suriname, Venezuela), Primocerusocellatus sp. nov. (Venezuela), Primoceruspetilus sp. nov. (Brazil), Primoceruspijiguaense sp. nov. (Venezuela), Primocerusmaipure sp. nov. (Venezuela), Primocerussemipubescens sp. nov. (Guyana), and Primocerusstriatolatus sp. nov. (Suriname). The genus Ephydrolithus gen. nov. is currently known to be restricted to seepages in the mountainous regions of the Brazilian Shield. Aulonochares gen. nov. and Primocerus gen. nov. are both currently only known from the Guiana Shield, though widespread in that region where they are associated with streams and seeps. We present differential diagnoses, maps, habitat details, and illustrations of all new genera and species here described.