A new papilionoid legume genus, Maraniona, is described based on recent collections from the Marañon Valley in northern Peru. The sister group relationships of Maraniona are analyzed using a combination of non-molecular and chloroplast DNA matK/trnK sequence data that incorporate comprehensive generic level sampling across the dalbergioid legumes. This analysis places Maraniona in a strongly supported subclade of the informal Pterocarpus clade of the dalbergioid legumes. We discuss the endemic status of Maraniona in relation to overall endemism in the upper Marañon Valley as well as the possible affinities of Maraniona to the genus Tipuana from Argentina and Bolivia.