Class Aves Linnaeus, 1758 - birds see Subclass Aves Linnaeus, 1758 Subclass Ornithurae Haeckel, 1866 see Clade Ornithurae Haeckel 1866 [Gauthier 1986] {Chiappe 1991} Infraclass Ratitae (Merrem, 1813) P. Brodkorb, 1963 see Parvclass Ratitae (Merrem, 1813) Order Rheiformes Forbes, 1884 see Suborder Rheae Forbes, 1884 Family †Opisthodactylidae Ameghino Genus †Opisthodactylus Ameghino, 1891