Opinions from R. E. Fordyce 1991
- 'Anthropodyptes gilli belongs to Anthropodyptes'
- 'Anthropornis nordenskjoldii is corrected as Anthropornis nordenskjoeldi and belongs to Anthropornis'
- 'Aptenodytes minor is recombined as Eudyptula minor'
- 'Aptenodytes ridgeni belongs to Aptenodytes'
- 'Archaeospheniscus lopdelli belongs to Archaeospheniscus'
- 'Archaeospheniscus lowei belongs to Archaeospheniscus'
- 'Austrosqualodon trirhizodonta belongs to Austrosqualodon'
- 'Mesoplodon compressus is a subjective synonym of Mesoplodon longirostris'
- 'Berardius arnuxii belongs to Berardius'
- 'Catarrhactes antipodes is recombined as Megadyptes antipodes'
- 'Cimoliasaurus maccoyi belongs to Cimoliasaurus'
- 'Cratochelone berneyi belongs to Cratochelone'
- 'Delphinus delphis belongs to Delphinus'
- 'Duntroonornis parvus belongs to Duntroonornis'
- 'Ichthyosaurus australis is recombined as Platypterygius australis'
- 'Kekenodon onamata is an invalid subgroup of Kekenodon'
- 'Korora oliveri belongs to Korora'
- 'Kronosaurus queenslandicus belongs to Kronosaurus'
- 'Lophocephalus parki is recombined as Mauicetus parki'
- 'Mammalodon colliveri belongs to Mammalodon'
- 'Mauicetus brevicollis is an invalid subgroup of Mauicetus'
- 'Mauicetus lophocephalus is an invalid subgroup of Mauicetus'
- 'Mauicetus waitakiensis is an invalid subgroup of Mauicetus'
- 'Mauisaurus haasti belongs to Mauisaurus'
- 'Microcetus hectori is an invalid subgroup of Microcetus'
- 'Moanasaurus mangahouangae belongs to Moanasaurus'
- 'Mosasaurus mokoroa belongs to Mosasaurus'
- 'Notochelys costata is recombined as Notochelone costata'
- 'Pachydyptes ponderosus belongs to Pachydyptes'
- 'Palaeeudyptes antarcticus belongs to Palaeeudyptes'
- 'Palaeeudyptes marplesi belongs to Palaeeudyptes'
- 'Palaeospheniscus novaezealandiae is recombined as Marplesornis novaezealandiae'
- 'Phocaenopsis mantelli belongs to Phocaenopsis'
- 'Physetodon baileyi belongs to Physetodon'
- 'Platydyptes amiesi belongs to Platydyptes'
- 'Platydyptes marplesi belongs to Platydyptes'
- 'Plesiocetus dyticus is an invalid subgroup of Plesiocetus'
- 'Prognathodon waiparaensis belongs to Prognathodon'
- 'Prosqualodon davidis belongs to Prosqualodon'
- 'Prosqualodon hamiltoni is an invalid subgroup of Prosqualodon'
- 'Prosqualodon marplesi is an invalid subgroup of Prosqualodon'
- 'Pseudaptenodytes macraei belongs to Pseudaptenodytes'
- 'Pseudaptenodytes minor belongs to Pseudaptenodytes'
- 'Pygoscelis tyreei belongs to Pygoscelis'
- 'Scaldicetus macgeei belongs to Scaldicetus'
- 'Scaptodon lodderi belongs to Scaptodon'
- 'Squalodon gambierensis is an invalid subgroup of Squalodon'
- 'Squalodon serratus is an invalid subgroup of Squalodon'
- 'Squalodon wilkinsoni is recombined as Parasqualodon wilkinsoni'
- 'Steno cudmorei is an invalid subgroup of Steno'
- 'Tangaroasaurus kakanuiensis belongs to Tangaroasaurus'
- 'Taniwhasaurus oweni belongs to Taniwhasaurus'
- 'Tylosaurus haumuriensis belongs to Tylosaurus'
- 'Woolungasaurus glendowerensis belongs to Woolungasaurus'
- 'Zeuglodon harwoodii is recombined as Metasqualodon harwoodi'
- 'Ziphius longirostris is recombined as Mesoplodon longirostris'