A new species and records of Helochares (Insecta: Coleoptera: Hydrophilidae) from Southeastern Brazil

A new species of Helochares Mulsant, 1844 (Hydrophilidae: Acidocerinae) from Brazil is described and illustrated. Helochares (s. str.) atlanticus sp. nov. is distinct mainly by characteristics of the aedeagus whose phalobase is short, narrowed on basal third; parameres are thick, constricted on apical quarter, with small tooth-like projection on outer margin near apex; dorsal lobe longer than ventral lobe, shorter than parameres, very wide at base, abruptly narrowing toward apex until about half of its length where it dilates and divides into two long and narrow projections apart from each other at base, but turned inward at apex; ventral lobe acuminate and symmetrical. The rounded emargination on anteromedial margin of labrum bearing small tooth-like projections and the convex and slightly elevated mesoventral process, without high-elevated carina, also helps in identifying the species. Specimens of the new species were collected in the mountain region of the state of Rio de Janeiro (municipality of Teresópolis) and in the north coast of the state of São Paulo (municipality of Ubatuba), both localities in Southeastern Brazil. Helochares (s. str.) oculatus Sharp, 1882 and Helochares (Sindolus) femoratus (Brullé, 1841) are recorded for the first time from the state of Rio de Janeiro