stem-group atlantogenatans. A position within Afrotheria has been argued to be unlikely on biogeographic grounds, and some of the afrotherian characteristics present in notoungulates have been refuted. Litopterns and notoungulates are the only South American ungulates to have gone extinct recently enough for molecular data to be available, so the relationships of astrapotheres, pyrotheres, and xenungulates must be determined based on morphology alone. The clade Sudamericungulata has been proposed to encompass astrapotheres, notoungulates, pyrotheres, and xenoungulates but not litopterns. Such a clade had been found in previous studies, but left unnamed. The study proposing the name Sudamericungulata found them to be afrotheres. Notes References Cenozoic mammals of South America Mammal unranked clades Prehistoric mammals of South America Ungulates Taxa named by Malcolm McKenna