New species, new records and key to the species of the group (Hemiptera, Heteroptera, Veliidae) from Brazil.

Background: Mayr, 1865 (Hemiptera, Heteroptera, Veliidae), known as riffle bugs, includes more than 400 species and is commonly found in tropical lotic environments, including coastal marine habitats, such as mangroves and estuaries. Due to the elevated number of species, the fauna from the Americas has been divided into several groups, which facilitates taxonomic studies. Amongst them, the group currently includes two species from the Greater Antilles and five from south-eastern and southern Brazil. Despite the many taxonomic studies developed during the past few decades, new species of are still being discovered in several areas of the continent, including the Atlantic Forest of eastern Brazil.

New Information: sp. n. is described, illustrated and compared with similar congeners. The new species belongs to the group and can be diagnosed by the uniformly black mesonotum, the presence of a tuft of setae medially on male abdominal sternum VII, the armature of the male hind femur and the distinctive shape of the paramere. In addition, we present new records of Bacon, 1948 from the States of Paraná and Santa Catarina and a key to the species of the group recorded from Brazil.