After Marsh, 1880, Feduccia, 1996, Tokaryk, Cumbaa & Storer, 1997, Galton & Martin, 2002, and Martin, Kurochkin & Tokaryk, 2012

<==o Hesperornithiformes Fürbringer, 1888 [Odontornithes Marsh, 1880, Odontognathe Stejneger, 1885 ]
   |?- †Potamornis skutchi Elzanowski, Paul & Stidham, 2000
   |?-o †Enaliornis Seeley, 1876 [Pelagornis Seeley, 1866 non Pelagornis Lartet, 1857 (Pelicaniformes: Osteodontornithes: Pelagornithidae) (nomen nudum)] [Enaliornithidae]
   |  |-- †E. barretti Seeley, 1876
   |  `-- †E. sedgwicki Seeley, 1876
   |?-o †Brodavis Martin, Kurochkin & Tokaryk, 2012 [Brodavidae Martin, Kurochkin & Tokaryk, 2012]
   |  |-- †B. americanus Martin, Kurochkin & Tokaryk, 2012
   |  |-- †B. baileyi Martin, Kurochkin & Tokaryk, 2012
   |  |-- †B. mongoliensis Martin, Kurochkin & Tokaryk, 2012
   |  `-- †B. varneri (Martin & Cordes-Person, 2007)
   `--+--o †Pasquiaornis Tokaryk, Cumbaa & Storer, 1997 [paraphyletic Baptornithidae American Ornithologist's Union, 1910]
      |  |-- †P. hardiei Tokaryk, Cumbaa & Storer, 1997
      |  `-- †P. tankei Tokaryk, Cumbaa & Storer, 1997
      `--+?- †Judinornis nogontsavensis Nesov & Borkin, 1983 [paraphyletic Baptornithidae American Ornithologist's Union, 1910]
         |-- †Baptornis advenus Marsh, 1877 [paraphyletic Baptornithidae American Ornithologist's Union, 1910]
         `--o †Hesperornithidae Marsh, 1880
            |-- †Canadaga arctica Hou, 1999
            |-- †Asiahesperornis bazhanovi Nesov & Prizemlin, 1991 [Asiahesperornithinae Nesov & Prizemlin, 1991]
            |-- †Parascaniornis stenisoei Lambrecht, 1933 [also classified as Charadriomorphae: Scaniornithidae]
            |-- †Hesperornithidae genera et species indet. [Central Asia]
            |-- †Parahesperornis alexi Martin, 1980 [Hesperornis gracilis]
            `--o †Hesperornis Marsh, 1872 [Lestornis Marsh, 1876; Coniornis Marsh, 1893; Hargeria Lucas, 1903]
               |-- †H. sp. [Nesov & Yarkov, 1993] [Central Asia, is NOT same as Hesperornithidae genera et species indet.]
               |-- †H. regalis Marsh, 1872
               |-- †H. crassipes (Marsh, 1876)
               |-- †H. gracilis Marsh, 1876 [Hargeria gracilis (Marsh) Lucas, 1903]
               |-- †H. altus (Marsh, 1893) [Coniornis altus Marsh, 1893]
               |-- †H. montana Schufeldt, 1915
               |-- †H. rossicus Nesov & Yarkov, 1993
               |-- †H. bairdi Martin & Lim, 2002
               |-- †H. chowi Martin & Lim, 2002
               |-- †H. macdonaldi Martin & Lim, 2002
               `-- †H. mengeli Martin & Lim, 2002


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