A new Neogomphus from South America, with extended comments on the phylogeny and biogeography of the Octogomphini trib. nov. (Anisoptera: Gomphidae)

N. edenticulatus sp. n. (<J holotype, 5 allotype: Lago Lacar at Estacion Forcstal Pucara, Neuquen Prov. Argentina, 30-1-81. O S. Flint, Jr.) is described and figured. The biology of Neogomphus species is discussed and a key to the adults presented along with a summary of their known distributions. The Octogomphini trib. nov. is established comprising Davidius, Fukienogomphus. Hemigomphus, Lanthus. Neogomhus. Octogomphus, Sinogomphus, Stylogomphus, and Trigomphus. Octogomphine phylogeny and biogeography is discussed and the group placed within the Gomphinae.