Opinions from G. G. Simpson 1945
- 'Acrodelphidae belongs to Delphinoidea'
- 'Acrodelphis belongs to Acrodelphidae'
- 'Acrotypotherium belongs to Mesotheriinae'
- 'Agabelus belongs to Delphinidae'
- 'Aglaocetus belongs to Cetotheriidae'
- 'Agorophiidae belongs to Squalodontoidea'
- 'Agorophius belongs to Agorophiidae'
- 'Agriocetus belongs to Archaeoceti'
- 'Alticamelinae belongs to Camelidae'
- 'Alticamelus belongs to Camelinae'
- 'Altomeryx is a nomen nudum'
- 'Amphicetus belongs to Cetotheriidae'
- 'Anisodelphis belongs to Iniinae'
- 'Anoplonassa belongs to Ziphiidae'
- 'Apenophyseter belongs to Hoplocetinae'
- 'Archaeoceti belongs to Cetacea'
- 'Archaeodelphis belongs to Archaeoceti'
- 'Argyrocetus belongs to Eurhinodelphidae'
- 'Argyrodelphis is a subjective synonym of Notocetus'
- 'Auchenia is a subjective synonym of Lama'
- 'Aulophyseter belongs to Hoplocetinae'
- 'Balaena belongs to Balaenidae'
- 'Balaenodon belongs to Physeterinae'
- 'Balaenoptera belongs to Balaenopteridae'
- 'Balaenopteridae belongs to Mysticeti'
- 'Balaenotus belongs to Balaenidae'
- 'Balaenula belongs to Balaenidae'
- 'Balanadae is corrected as Balaenidae and belongs to Mysticeti'
- 'Basilosauridae belongs to Archaeoceti'
- 'Basilosaurus belongs to Basilosauridae'
- 'Belemnoziphius belongs to Ziphiidae'
- 'Belosphys belongs to Delphinidae'
- 'Berardiopsis belongs to Ziphiidae'
- 'Berardius belongs to Ziphiidae'
- 'Bravardia belongs to Mesotheriinae'
- 'Burtinopsis belongs to Balaenopteridae'
- 'Camelinae belongs to Camelidae'
- 'Camelodon belongs to Poebrotheriinae'
- 'Camelops belongs to Camelinae'
- 'Camelus belongs to Camelinae'
- 'Cephalorhynchus belongs to Delphinidae'
- 'Cephalotropis belongs to Cetotheriidae'
- 'Cetacea belongs to Mutica'
- 'Ceterhinops belongs to Delphinidae'
- 'Cetotheriinae was reranked as the family Cetotheriidae and belongs to Mysticeti'
- 'Cetotheriomorphus [misspelled as Cetotheriomorphis] belongs to Cetotheriidae'
- 'Cetotheriopsis belongs to Cetotheriidae'
- 'Cetotherium belongs to Cetotheriidae'
- 'Cetotheriophanes is a subjective synonym of Balaenoptera'
- 'Cetotherium (Eucetotherium) was reranked as Eucetotherium and belongs to Cetotheriidae'
- 'Cetotherium (Plesiocetopsis) was reranked as Plesiocetopsis and belongs to Cetotheriidae'
- 'Champsodelphis belongs to Acrodelphidae'
- 'Choneziphius belongs to Ziphiidae'
- 'Colophonodon belongs to Squalodontidae'
- 'Cophocetus belongs to Cetotheriidae'
- 'Cosoryx (Paracosoryx) is an invalid subgroup of Merycodus'
- 'Cyrtodelphis is a subjective synonym of Schizodelphis'
- 'Delphinapterus belongs to Monodontidae'
- 'Delphinapterus (Hemisyntrachelus) was reranked as Hemisyntrachelus and belongs to Hemisyntrachelidae'
- 'Delphinavus belongs to Delphinidae'
- 'Delphinidae belongs to Delphinoidea'
- 'Delphinodon belongs to Delphinidae'
- 'Delphinoidea belongs to Odontoceti'
- 'Delphinopsis belongs to Delphinidae'
- 'Delphinus belongs to Delphinidae'
- 'Delphinus (Grampus) was reranked as Grampus and belongs to Delphinidae'
- 'Diaphorocetus belongs to Hoplocetinae'
- 'Dinoziphius belongs to Physeterinae'
- 'Diochotichus is a subjective synonym of Notocetus'
- 'Dorudon belongs to Dorudontidae'
- 'Dorudontidae belongs to Archaeoceti'
- 'Dyseotylopus belongs to Camelinae'
- 'Eboroziphius belongs to Ziphiidae'
- 'Elephas americanus is recombined as Mammut americanum'
- 'Eocetus belongs to Protocetidae'
- 'Eoplatanista belongs to Acrodelphidae'
- 'Eotylopus belongs to Poebrotheriinae'
- 'Epitriplopus belongs to Triplopodinae'
- 'Eubalaena belongs to Balaenidae'
- 'Eurhinodelphidae belongs to Delphinoidea'
- 'Eurhinodelphis belongs to Eurhinodelphidae'
- 'Eutypotherium belongs to Mesotheriinae'
- 'Gigantocamelus belongs to Camelinae'
- 'Globicephala belongs to Delphinidae'
- 'Gnathabelodontinae is a subjective synonym of Gomphotheriinae'
- 'Grypolithax belongs to Delphinidae'
- 'Hemisyntrachelidae belongs to Delphinoidea'
- 'Herpetocetus belongs to Cetotheriidae'
- 'Hesperocetus belongs to Iniinae'
- 'Heterocetus belongs to Cetotheriidae'
- 'Heterodelphis belongs to Acrodelphidae'
- 'Hexameryx is a subjective synonym of Hexobelomeryx'
- 'Hoplocetinae belongs to Physeteridae'
- 'Hoplocetus belongs to Hoplocetinae'
- 'Hyperoodon belongs to Ziphiidae'
- 'Idiocetus belongs to Balaenopteridae'
- 'Idiophyseter belongs to Physeterinae'
- 'Idiorophus belongs to Hoplocetinae'
- 'Inia belongs to Iniinae'
- 'Iniinae belongs to Platanistidae'
- 'Iniopsis belongs to Delphinidae'
- 'Interatheridae is corrected as Interatheriidae and belongs to Typotheria'
- 'Interatheriinae belongs to Interatheriidae'
- 'Ischyrorhynchus belongs to Iniinae'
- 'Isocetus belongs to Cetotheriidae'
- 'Ixacanthus belongs to Delphinidae'
- 'Kekenodon belongs to Dorudontidae'
- 'Kentriodon belongs to Delphinidae'
- 'Kogia belongs to Kogiinae'
- 'Kogiinae belongs to Physeteridae'
- 'Kogiopsis belongs to Kogiinae'
- 'Lagenorhynchus belongs to Delphinidae'
- 'Lama belongs to Camelinae'
- 'Lamprolithax belongs to Delphinidae'
- 'Liolithax belongs to Delphinidae'
- 'Lipotes belongs to Iniinae'
- 'Lissodelphis belongs to Delphinidae'
- 'Lonchodelphis belongs to Stenodelphininae'
- 'Lophocetus belongs to Hemisyntrachelidae'
- 'Loxolithax belongs to Delphinidae'
- 'Macrochirifer belongs to Delphinidae'
- 'Mauicetus belongs to Cetotheriidae'
- 'Megacamelus belongs to Camelinae'
- 'Megaptera belongs to Balaenopteridae'
- 'Megapteropsis belongs to Balaenopteridae'
- 'Merychyinae belongs to Merycoidodontidae'
- 'Merycochoerus (Brachycrus) was reranked as Brachycrus and belongs to Merycochoerinae'
- 'Mesocetus belongs to Cetotheriidae'
- 'Mesocetus is replaced by Eocetus'
- 'Mesocetus is a subjective synonym of Diaphorocetus'
- 'Mesoplodon belongs to Ziphiidae'
- 'Mesoplodon (Cetorhynchus) was reranked as Cetorhynchus and belongs to Ziphiidae'
- 'Mesoteras belongs to Balaenopteridae'
- 'Mesotherium belongs to Mesotheriinae'
- 'Metasqualodon belongs to Squalodontidae'
- 'Metopocetus belongs to Cetotheriidae'
- 'Microcetus belongs to Squalodontidae'
- 'Microsqualodon belongs to Squalodontidae'
- 'Microzeuglodon belongs to Archaeoceti'
- 'Miolabis belongs to Camelinae'
- 'Miolabis (Paratylopus) was reranked as Paratylopus and belongs to Camelinae'
- 'Mioziphius is a subjective synonym of Ziphirostrum'
- 'Mixocetus belongs to Cetotheriidae'
- 'Mixodectoidea belongs to Insectivora'
- 'Monodon belongs to Monodontidae'
- 'Monodontidae belongs to Delphinoidea'
- 'Morenocetus belongs to Balaenidae'
- 'Mutica belongs to Eutheria'
- 'Mycetes is a subjective synonym of Alouatta'
- 'Mysticeti belongs to Cetacea'
- 'Nannolithax belongs to Delphinidae'
- 'Neobalaena belongs to Balaenidae'
- 'Neomeris is a subjective synonym of Neophocaena'
- 'Neophocaena belongs to Phocaenidae'
- 'Neosqualodon belongs to Squalodontidae'
- 'Notiocetus belongs to Balaenopteridae'
- 'Notocetus belongs to Ziphiidae'
- 'Notopithecidae was reranked as the subfamily Notopithecinae and belongs to Interatheriidae'
- 'Odocoileini belongs to Odocoileinae'
- 'Odontoceti belongs to Cetacea'
- 'Oedolithax belongs to Delphinidae'
- 'Ontocetus belongs to Physeterinae'
- 'Orca is a subjective synonym of Orcinus'
- 'Orca (Orcaella) was reranked as Orcaella and belongs to Delphinidae'
- 'Orcinus belongs to Delphinidae'
- 'Orycterocetus belongs to Physeterinae'
- 'Oxydactylus belongs to Camelinae'
- 'Pachyacanthus belongs to Platanistinae'
- 'Pachycetus belongs to Cetotheriidae'
- 'Palaeocetus belongs to Balaenopteridae'
- 'Palaeolama belongs to Camelinae'
- 'Palaeophocaena belongs to Phocaenidae'
- 'Palaeoziphius belongs to Ziphiidae'
- 'Pappocetus belongs to Protocetidae'
- 'Parasqualodon belongs to Squalodontidae'
- 'Parietobalaena belongs to Cetotheriidae'
- 'Patriocetus belongs to Archaeoceti'
- 'Peripolocetus belongs to Cetotheriidae'
- 'Phoberodon belongs to Squalodontidae'
- 'Phocaena belongs to Phocaenidae'
- 'Phocaenina was reranked as the family Phocaenidae and belongs to Delphinoidea'
- 'Phocaenopsis belongs to Phocaenidae'
- 'Phococetus belongs to Dorudontidae'
- 'Phocaenoides is a subjective synonym of Phocaena'
- 'Physeter belongs to Physeterinae'
- 'Physeteridae belongs to Physeteroidea'
- 'Physeterinae belongs to Physeteridae'
- 'Physeteroidea belongs to Odontoceti'
- 'Physeterula belongs to Physeterinae'
- 'Physetodon belongs to Physeterinae'
- 'Pithanodelphis belongs to Delphinidae'
- 'Platanista belongs to Platanistinae'
- 'Platanistina was reranked as the family Platanistidae and belongs to Platanistoidea'
- 'Platanistinae belongs to Platanistidae'
- 'Platanistoidea belongs to Odontoceti'
- 'Platylithax belongs to Delphinidae'
- 'Platyosphys belongs to Basilosauridae'
- 'Plesiocetus belongs to Balaenopteridae'
- 'Pliauchenia belongs to Camelinae'
- 'Pliauchenia (Megatylopus) was reranked as Megatylopus and belongs to Camelinae'
- 'Poabromylus belongs to Poebrotheriinae'
- 'Poebrotheriidae is a subjective synonym of Poebrotheriinae'
- 'Poebrotheriinae belongs to Camelidae'
- 'Poebrotherium belongs to Poebrotheriinae'
- 'Pomatodelphis belongs to Acrodelphidae'
- 'Pontistes belongs to Stenodelphininae'
- 'Pontivaga belongs to Stenodelphininae'
- 'Pontoplanodes is a subjective synonym of Saurodelphis'
- 'Pontoporia is a subjective synonym of Stenodelphis'
- 'Prioinia is corrected as Proinia and belongs to Iniinae'
- 'Priscophyseter belongs to Physeterinae'
- 'Procamelus belongs to Camelinae'
- 'Prochenia is a nomen nudum'
- 'Prodelphinus belongs to Delphinidae'
- 'Prophyseter belongs to Physeterinae'
- 'Prosqualodon belongs to Squalodontidae'
- 'Protobalaena belongs to Balaenidae'
- 'Protocetidae belongs to Archaeoceti'
- 'Protocetus belongs to Protocetidae'
- 'Protodelphinus belongs to Delphinidae'
- 'Protolabinae is a subjective synonym of Camelinae'
- 'Protolabis belongs to Camelinae'
- 'Protomeryx belongs to Camelinae'
- 'Protophocaena belongs to Phocaenidae'
- 'Protoziphius is corrected as Proroziphius and belongs to Ziphiidae'
- 'Protylopus belongs to Poebrotheriinae'
- 'Prozeuglodon belongs to Basilosauridae'
- 'Pseudoceras belongs to Camelidae'
- 'Pseudolabidinae belongs to Camelidae'
- 'Pseudolabis belongs to Pseudolabidinae'
- 'Pseudorca belongs to Delphinidae'
- 'Pseudotypotherium belongs to Mesotheriinae'
- 'Rakomylus belongs to Stenomylinae'
- 'Rhachianectidae belongs to Mysticeti'
- 'Rhegnopsis belongs to Cetotheriidae'
- 'Rhynchippidae was reranked as the subfamily Rhynchippinae and belongs to Notohippidae'
- 'Rhytisodon belongs to Squalodontidae'
- 'Saurocetes is replaced by Saurodelphis'
- 'Saurocetus belongs to Squalodontidae'
- 'Saurodelphis belongs to Iniinae'
- 'Scaldicetus belongs to Hoplocetinae'
- 'Schizodelphis belongs to Acrodelphidae'
- 'Sibbaldus belongs to Balaenopteridae'
- 'Siphonocetus belongs to Cetotheriidae'
- 'Sotalia belongs to Delphinidae'
- 'Squalodelphis belongs to Ziphiidae'
- 'Squalodon belongs to Squalodontidae'
- 'Squalodontidae belongs to Squalodontoidea'
- 'Squalodontoidea belongs to Odontoceti'
- 'Steno belongs to Delphinidae'
- 'Stenodelphininae belongs to Platanistidae'
- 'Stenodelphis belongs to Stenodelphininae'
- 'Stenomylinae belongs to Camelidae'
- 'Stenomylus belongs to Stenomylinae'
- 'Stereodelphis belongs to Delphinidae'
- 'Tanupolama belongs to Camelinae'
- 'Tasmacetus belongs to Ziphiidae'
- 'Thalassocetus belongs to Physeterinae'
- 'Tiphyocetus belongs to Cetotheriidae'
- 'Titanotylopus belongs to Camelinae'
- 'Tretosphys belongs to Delphinidae'
- 'Tretulias belongs to Cetotheriidae'
- 'Triplopodidae was reranked as the subfamily Triplopodinae and belongs to Hyracodontidae'
- 'Triplopus belongs to Triplopodinae'
- 'Trirhizodon belongs to Squalodontidae'
- 'Tursiops belongs to Delphinidae'
- 'Typotheria belongs to Notoungulata'
- 'Typothericulus belongs to Mesotheriinae'
- 'Typotheridion belongs to Mesotheriinae'
- 'Typotheriodon belongs to Mesotheriinae'
- 'Typotheriopsis belongs to Mesotheriinae'
- 'Ulias belongs to Cetotheriidae'
- 'Xenorophus belongs to Agorophiidae'
- 'Zarhachis belongs to Platanistinae'
- 'Zeuglodon is a subjective synonym of Basilosaurus'
- 'Ziphiidae was reranked as the tribe Ziphiina and belongs to Physeteroidea'
- 'Ziphiodelphis belongs to Eurhinodelphidae'
- 'Ziphioides belongs to Ziphiidae'
- 'Ziphirostrum belongs to Ziphiidae'
- 'Ziphius belongs to Ziphiidae'
- 'Zygorhiza belongs to Dorudontidae'