The genus Oligoclada in Argentina, with description of O. rubribasalis sp. nov. (Odonata: Libellulidae)

Abstract A new species (holotype ♂ in MLP: Argentina, Formosa province, Parque Nacional Río Pilcomayo, Laguna Blanca, marshes next to pond, 25°10′29″S, 58°07′44″W, 74 m a.s.l., 16/17 ii 2008, leg. NvE, RWG) is described, diagnosed and illustrated, and a key, diagnostic illustrations, and distribution maps are provided for the three species of the genus occurring in Argentina. The combination of well defined orange-red dorsal spots on S2-3 in mature specimens, well developed supplementary tooth in pretarsal claws, shape of occipital triangle of female, and of vesica spermalis, genital lobe, posterior hamule, and cercus of male diagnose the new species.