After Olson, 1985, Ericson, 1995, Feduccia, 1996, Mayr, Peters & Rietschel, 2002, and Peterson, 2002-2004, with Finnish vernacular names from Lokki, Jännes & Nikander, 1992

<==o Procellariiformes Fürbringer, 1888 (Albatrosses and petrels; ulappalinnut)
   |?- †Lonchodytes estesi Brodkorb, 1963 sensu Hope, 2002 [Lonchodytidae] [jr. synon. to Graculavidae?]
   |?- †Tytthostonyx glauconiticus Olson & Parris, 1987 E. Paleoc. ENA. [Tytthostonychidae]
   |--o †Diomedeoididae Fischer 1985
   |  |?- †Rupelornis definitus van Beneden, 1871 [nomina dubia]
   |  `--o †Diomedeoides Fischer, 1985 [Frigidafrons Cheneval, 1995]
   |     |-- †D. brodkorbi (Cheneval, 1995) [Frigidafrons brodkorbi Cheneval, 1995]
   |     |-- †D. lipsiensis (Fischer, 1983) [Gaviota lipsiensis Fischer, 1983; ?Rupelornis definitus van Beneden, 1871; Diomedeoides minimus Fischer, 1985; Frigidafrons brodkorbi Cheneval, 1995]
   |     |-- †D. babaheydariensis Peters & Hamedani, 2000
   |     `-- †D. sp. [L. Olig. Germany] [Mayr, Peters & Rietschel, 2002]
   `--+-- Diomedeidae Gray, 1840 [Diomedaedae] (Albatrosses; albatrossit)
      `--+-- Hydrobatidae [Oceanitidae Forbes, 1882] (ulappakeijut)
         `-- Procellariidae Vigors, 1825 [non Leach, 1820?] [incl. Pelecanoididae Gray, 1871] (Petrels; Ulappaliitajät)

After Livezey & Zusi, 2007

<==o Procellariiformes
   |--o Pelecanoidi
   |  `-- Pelecanoididae
   `--o Procellarae
      |--o Oceanitoidea
      |  `-- Oceanitidae [Hydrobatidae]
      `--o Procellarioidea
         |-- Procellariidae
         `-- Diomedeidae

Reference(s):