A new genus of huntsman spiders (Araneae, Sparassidae, Sparianthinae) from the Neotropical region.

Uaiuara gen. nov. is described to include Sparianthis amazonica Simon from Brazil, Sparianthis barroana Chamberlin from Panama, and five new species, namely: Uaiuara quyguaba sp. nov. from the states of Amazonas, Pará and Amapá; Uaiuara ope sp. nov. from Acre and Uaiuara jirau sp. nov. from Rondônia, all in northern Brazil, Uaiuara palenque sp. nov. from Ecuador and Uaiuara dianae sp. nov. from Peru. The genus is easily distinguished from the remaining Neotropical Sparianthinae by the very recurved anterior eye row, the large number of ventral spines on tibiae of legs I-II, the retrolateral grove on the male palpal cymbium and the convoluted duct system of the female vulva. In addition, the female of S. barroana and the male of S. amazonica are described for the first time. The latter species is newly recorded from Colombia, Suriname, Ecuador and Bolivia.