Class Aves Linnaeus, 1758 - birds see Subclass Aves Linnaeus, 1758 Subclass Ornithurae Haeckel, 1866 see Clade Ornithurae Haeckel 1866 [Gauthier 1986] {Chiappe 1991} Order †Gansuiornithiformes nom. imperf. see Order Gansuiformes Hou & Liu, 1984 1 Family †Gansuiornithidae see Family Gansuidae Hou & Liu, 1984