Class Aves Linnaeus, 1758 - birds see Subclass Aves Linnaeus, 1758
   Subclass Ornithurae Haeckel, 1866 see Clade Ornithurae Haeckel 1866 [Gauthier 1986] {Chiappe 1991}
     Order †Yixianornithiformes Zhou & Zhang, 2006
       1 Family †Yixianornithidae Zhou & Zhang, 2006