Urania sloanus is similar to other Urania species but the only one with a suffusion of metallic orange scales on the upper hindwing. In this respect it is reminiscent of the genus Chrysiridia from Madagascar and Tanzania. Smaller than other species on average, especially in the male.
Sister taxon of U. sloanus as yet unknown, but there are up to five other species of Urania (Lees and Smith, 1991).
The genus Urania is considered to be the sister of Chrysiridia (Lees and Smith, 1991).