The southern Neotropical genus Anahi Martínez is comprehensively revised and now includes three species: A. dentata Ocampo Ruiz-Manzanos new species, A. guaraniticus Martínez, and A. oblivia Ocampo Ruiz-Manzanos new species. The new species extend the distribution of the genus from Paraguay and Bolivia to Argentina. A. guaraniticus is redescribed and the characters that define the genus are extended to include A. dentata and A. oblivia. Descriptions, diagnosis illustrations, distribution maps and a key to all species of the genus are provided. The biogeography of the genus and its systematic placement within Melolonthinae are here discussed.