Class Aves Linnaeus, 1758 - birds see Subclass Aves Linnaeus, 1758
Count: -
   Subclass †Sauriurae Haeckel, 1866 see Subclass Archaeornithes Gadow, 1893
  Count: -
     Infraclass †Enantiornithes Walker, 1981
    Count: [†g] †2o;3f;19g;7s [21 Mar 2017]
       Order †Alexornithiformes Brodkorb, 1976
      Count: [†g] †2f;13g;2s [21 Mar 2017]
         Family †Alexornithidae Brodkorb, 1976
        Count: [†g] †8g;2s [21 Mar 2017]
           1 Genus †Alexornis Brodkorb, 1976 [monotypic]
          Count: [†*] †1s [21 Mar 2017]
           2 Genus †Kizylkumavis Nessov, 1984
          Count: -
           3 Genus †Sazavis Nessov & Yarkov, 1989 [monotypic]
          Count: [†*] †1s [21 Mar 2017]
           4 Genus †Nanantius Molnar, 1986
          Count: [†*] †2s [21 Mar 2017]
           5 Genus †Gobipteryx Elżanowski, 1974 [monotypic]
          Count: [†*] †1s [21 Mar 2017]
           6 Genus †Neuquenornis Chiappe & Calvo, 1994
          Count: -
           7 Genus †Zhyraornis Nessov, 1984
          Count: †1s
           8 Genus †Lenesornis Kurochkin, 1996 [monotypic]
          Count: [†*] †1s [21 Mar 2017]