After Livezey & Zusi, 2007, and Nesbitt, Ksepka & Clarke, 2011

<==o Pelecanimorphae Huxley, 1867
   |?-o Odontopterygiformes (Spulski, 1910) [Odontopterygia]
   |  `-- †Odontopterygidae Lambrecht, 1933 [Pelagornithidae Fürbringer, 1888] (valehammaslinnut)
   |--o Balaenicipitiformes (Sclater, 1924) (shoebills; kenkänokat)
   |  `-- Balaenicipitidae (Sclater, 1924) (shoebills; kenkänokat)
   `--o Pelecaniformes Sharpe, 1891 (pelecans, sulas, anhingas and cormorant & shags; pelikaanilinnut)
      |--o Phaethontes (Sharpe, 1891)
      |  |-- †Prophaethontidae
      |  `-- Phaethontidae Brandt, 1831 (jouhipyrstöt)
      `--o Steganopodes (Chandler, 1916)
         |--o Fregatides (Sharpe, 1891) [Fregatae]
         |  `--o Fregatoidea (Garrod, 1974)
         |     `-- Fregatidae Garrod, 1874 (kaapparit)
         `--o Pelecanides (Sharpe, 1891)
            |--o Pelecanida (Sharpe, 1891 sensu Livezey & Zusi, 2007 [Pelecani]
            |  `-- Pelecanidae Vigors, 1825 (pelikaanit)
            `--o Sulida (Reichenbach, 1849) sensu Livezey & Zusi, 2007 [Sulae]
               |--o Suloidea (Reichenbach, 1849)
               |  `-- Sulidae (Reichenbach, 1849) (suulat)
               `--o Phalacorcoracoidea (Bonaparte, 1854)
                  |-- Phalacrocoracidae (Bonaparte, 1854) (merimetsot)
                  `--+-- †Plotopteridae Howard, 1969 (pingviinisuulat)
                     `-- Anhingidae Ridgeway, 1887 (käärmekaulat)

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