Opinions from A. Berta 2017
- 'Acrophoca belongs to Monachinae'
- 'Acrophyseter belongs to Panphyseteroidea'
- 'Aegyptocetus belongs to Protocetidae'
- 'Aetiocetidae belongs to Mysticeti'
- 'Aetiocetus belongs to Aetiocetidae'
- 'Africanacetus belongs to Ziphiidae'
- 'Afrophoca belongs to Monachinae'
- 'Aglaocetus belongs to Cetotheriidae'
- 'Agorophiidae belongs to Odontoceti'
- 'Agorophius belongs to Agorophiidae'
- 'Aivukus belongs to Odobeninae'
- 'Albertocetus belongs to Xenorophidae'
- 'Albicetus belongs to Panphyseteroidea'
- 'Albireo belongs to Albireonidae'
- 'Albireonidae belongs to Delphinoidea'
- 'Allodelphinidae belongs to Platanistoidea'
- 'Allodelphis belongs to Allodelphinidae'
- 'Allodesmus belongs to Desmatophocidae'
- 'Ambulocetidae belongs to Cetacea'
- 'Ambulocetus belongs to Ambulocetidae'
- 'Ancalecetus belongs to Basilosauridae'
- 'Andrewsiphius belongs to Remingtonocetidae'
- 'Anisosiren belongs to Dugongidae'
- 'Anomotherium belongs to Trichechidae'
- 'Anoplonassa belongs to Ziphiidae'
- 'Aporotus belongs to Ziphiidae'
- 'Aprixokogia belongs to Kogiidae'
- 'Archaebalaenoptera belongs to Balaenopteridae'
- 'Archaeodelphis belongs to Odontoceti'
- 'Archaeodobenus belongs to Odobenidae'
- 'Archaeoparadoxia belongs to Paleoparadoxiidae'
- 'Archaeophocaena belongs to Phocoenidae'
- 'Archaeoziphius belongs to Ziphiidae'
- 'Archaeschrichtius belongs to Eschrichtiidae'
- 'Arctoidea was reranked as a unranked clade and belongs to Carnivora'
- 'Argyrocetus belongs to Odontoceti'
- 'Arimidelphis belongs to Delphinidae'
- 'Arktocara belongs to Allodelphinidae'
- 'Artiocetus belongs to Protocetidae'
- 'Ashleycetidae belongs to Odontoceti'
- 'Ashleycetus belongs to Ashleycetidae'
- 'Ashokia belongs to Protosirenidae'
- 'Ashoroa belongs to Desmostylia'
- 'Ashorocetus belongs to Aetiocetidae'
- 'Astadelphis belongs to Delphinidae'
- 'Atopotarus belongs to Desmatophocidae'
- 'Attockicetus belongs to Remingtonocetidae'
- 'Aulocetus belongs to Tranatocetidae'
- 'Aulophyseter belongs to Physeteridae'
- 'Auroracetus belongs to Pontoporiidae'
- 'Australithax belongs to Phocoenidae'
- 'Australodelphis belongs to Delphinidae'
- 'Australophoca belongs to Monachinae'
- 'Awamokoa belongs to Waipatiidae'
- 'Babiacetus belongs to Protocetidae'
- 'Balaena belongs to Balaenidae'
- 'Balaenella belongs to Balaenidae'
- 'Balaenomorpha belongs to Chaeomysticeti'
- 'Balaenoptera belongs to Balaenopteridae'
- 'Balaenopteridae belongs to Balaenopteroidea'
- 'Balaenopteroidea was reranked as a unranked clade and belongs to Thalassotherii'
- 'Balaenula belongs to Balaenidae'
- 'Balanadae is corrected as Balaenidae and belongs to Balaenomorpha'
- 'Basilosauridae belongs to Pelagiceti'
- 'Basilosaurus belongs to Basilosauridae'
- 'Basiloterus belongs to Basilosauridae'
- 'Basilotritus belongs to Basilosauridae'
- 'Batavipusa belongs to Phocinae'
- 'Behemotops belongs to Desmostylia'
- 'Belemnoziphius belongs to Ziphiidae'
- 'Belonodelphis belongs to Kentriodontidae'
- 'Beneziphius belongs to Ziphiidae'
- 'Bharatisiren belongs to Dugonginae'
- 'Bohaskaia belongs to Monodontidae'
- 'Brachyallodesmus belongs to Desmatophocidae'
- 'Brachydelphis belongs to Pontoporiidae'
- 'Brandtocetus belongs to Cetotheriidae'
- 'Brujadelphis belongs to Inioidea'
- 'Brygmophyseter belongs to Panphyseteroidea'
- 'Callistosiren belongs to Dugonginae'
- 'Callophoca belongs to Monachinae'
- 'Caperea belongs to Neobalaenidae'
- 'Carolinacetus belongs to Protocetidae'
- 'Caviziphius belongs to Ziphiidae'
- 'Cephalotropis belongs to Cetotheriidae'
- 'Cetacea was reranked as a unranked clade and belongs to Cetartiodactyla'
- 'Ceterhinops belongs to Eurhinodelphinidae'
- 'Cetotheriinae was reranked as the family Cetotheriidae and belongs to Thalassotherii'
- 'Cetotheriopsis belongs to Thalassotherii'
- 'Cetotherium belongs to Cetotheriidae'
- 'Cetotherium (Cetotheriophanes) was reranked as Cetotheriophanes and belongs to Balaenopteridae'
- 'Cetotherium (Eucetotherium) was reranked as Eucetotherium and belongs to Cetotheriidae'
- 'Cetotherium (Plesiocetopsis) was reranked as Plesiocetopsis and belongs to Tranatocetidae'
- 'Chaeomysticeti belongs to Mysticeti'
- 'Chavinziphius belongs to Ziphiidae'
- 'Chimuziphius belongs to Ziphiidae'
- 'Chonecetus belongs to Aetiocetidae'
- 'Choneziphius belongs to Ziphiidae'
- 'Chrysocetus belongs to Basilosauridae'
- 'Cophocetus belongs to Cetotheriidae'
- 'Cornwallius belongs to Desmostylia'
- 'Corystosiren belongs to Dugonginae'
- 'Cotylocara belongs to Odontoceti'
- 'Crenatocetus belongs to Protocetidae'
- 'Crenatosiren belongs to Dugonginae'
- 'Cryptophoca belongs to Phocinae'
- 'Cynthiacetus belongs to Basilosauridae'
- 'Dagonodum belongs to Ziphiidae'
- 'Dalanistes belongs to Remingtonocetidae'
- 'Delphinapterus belongs to Monodontidae'
- 'Delphinapterus (Hemisyntrachelus) was reranked as Hemisyntrachelus and belongs to Delphinidae'
- 'Delphinida belongs to Odontoceti'
- 'Delphinidae belongs to Delphinoidea'
- 'Delphinodon belongs to Kentriodontidae'
- 'Delphinoidea belongs to Delphinida'
- 'Denebola belongs to Monodontidae'
- 'Desmatophoca belongs to Desmatophocidae'
- 'Desmatophocidae belongs to Pinnipedia'
- 'Desmostylus belongs to Desmostylia'
- 'Devinophoca belongs to Phocidae'
- 'Dhedacetus belongs to Protocetidae'
- 'Diaphorocetus belongs to Panphyseteroidea'
- 'Dioplotherium belongs to Dugonginae'
- 'Diorocetus belongs to Cetotheriidae'
- 'Diunatans belongs to Eschrichtiidae'
- 'Domningia belongs to Dugonginae'
- 'Dorudon belongs to Basilosauridae'
- 'Dugongidae belongs to Sirenia'
- 'Dugonginae belongs to Dugongidae'
- 'Dusignathinae belongs to Odobenidae'
- 'Dusignathus belongs to Dusignathinae'
- 'Dusisiren belongs to Hydrodamalinae'
- 'Eboroziphius belongs to Ziphiidae'
- 'Echovenator belongs to Xenorophidae'
- 'Enaliarctos belongs to Pinnipedimorpha'
- 'Eobalaenoptera belongs to Balaenopteridae'
- 'Eocetus belongs to Protocetidae'
- 'Eodelphinus belongs to Delphinidae'
- 'Eomysticetidae belongs to Chaeomysticeti'
- 'Eomysticetus belongs to Eomysticetidae'
- 'Eoplatanista belongs to Eoplatanistidae'
- 'Eoplatanistidae belongs to Odontoceti'
- 'Eosiren belongs to Dugongidae'
- 'Eotaria belongs to Otariidae'
- 'Eotheroides belongs to Dugongidae'
- 'Eschrichtiidae belongs to Balaenopteroidea'
- 'Eschrichtioides belongs to Eschrichtiidae'
- 'Etruridelphis belongs to Delphinidae'
- 'Eudelphis belongs to Panphyseteroidea'
- 'Eurhinodelphidae is corrected as Eurhinodelphinidae and belongs to Delphinoidea'
- 'Eurhinodelphis belongs to Eurhinodelphinidae'
- 'Ferecetotherium belongs to Physeteridae'
- 'Fragilicetus belongs to Balaenopteridae'
- 'Fucaia belongs to Aetiocetidae'
- 'Gandakasia belongs to Ambulocetidae'
- 'Gaviacetus belongs to Protocetidae'
- 'Georgiacetus belongs to Protocetidae'
- 'Globicetus belongs to Ziphiidae'
- 'Goedertius belongs to Allodelphinidae'
- 'Gomphotaria belongs to Dusignathinae'
- 'Goniodelphis belongs to Iniidae'
- 'Gricetoides belongs to Eschrichtiidae'
- 'Gryphoca belongs to Phocinae'
- 'Haborophocoena belongs to Phocoenidae'
- 'Hadrodelphis belongs to Kentriodontidae'
- 'Hadrokirus belongs to Monachinae'
- 'Halicetus belongs to Chaeomysticeti'
- 'Halitherium (Prototherium) was reranked as Prototherium and belongs to Dugongidae'
- 'Herentalia belongs to Cetotheriidae'
- 'Herpetocetus belongs to Cetotheriidae'
- 'Heterodelphis belongs to Kentriodontidae'
- 'Hibacetus belongs to Cetotheriidae'
- 'Himalayacetus belongs to Ambulocetidae'
- 'Homiphoca belongs to Monachinae'
- 'Huaridelphis belongs to Odontoceti'
- 'Hydrarctos belongs to Otariidae'
- 'Hydrodamalidae was reranked as the subfamily Hydrodamalinae and belongs to Dugongidae'
- 'Hydrodamalis belongs to Hydrodamalinae'
- 'Ichthyolestes belongs to Pakicetidae'
- 'Idiocetus belongs to Balaenidae'
- 'Idiophyseter belongs to Panphyseteroidea'
- 'Idiorophus belongs to Panphyseteroidea'
- 'Ihlengesi belongs to Ziphiidae'
- 'Imagotaria belongs to Odobenidae'
- 'Imerocetus belongs to Cetotheriidae'
- 'Imocetus belongs to Ziphiidae'
- 'Incacetus belongs to Kentriodontidae'
- 'Incakujira belongs to Balaenopteridae'
- 'Indocetus belongs to Protocetidae'
- 'Indosiren belongs to Dugongidae'
- 'Inia belongs to Iniidae'
- 'Iniana was reranked as the family Iniidae and belongs to Inioidea'
- 'Inioidea belongs to Delphinida'
- 'Iniopsis belongs to Eurhinodelphinidae'
- 'Isanacetus belongs to Cetotheriidae'
- 'Ischyrorhynchus belongs to Iniidae'
- 'Isocetus belongs to Thalassotherii'
- 'Isthminia belongs to Kentriodontidae'
- 'Izikoziphius belongs to Ziphiidae'
- 'Janjucetus belongs to Mammalodontidae'
- 'Joumocetus belongs to Cetotheriidae'
- 'Kampholophos belongs to Kentriodontidae'
- 'Kamtschatarctos belongs to Odobenidae'
- 'Kawas belongs to Phocinae'
- 'Kekenodontinae was reranked as the family Kekenodontidae and belongs to Pelagiceti'
- 'Kentriodon belongs to Kentriodontidae'
- 'Kentriodontidae belongs to Delphinida'
- 'Kharodacetus belongs to Protocetidae'
- 'Kogia belongs to Kogiidae'
- 'Kogiidae belongs to Physeteroidea'
- 'Kronokotherium belongs to Desmostylia'
- 'Kurdalagonus belongs to Cetotheriidae'
- 'Kutchicetus belongs to Remingtonocetidae'
- 'Kutchisiren belongs to Dugonginae'
- 'Lagenorhynchus belongs to Delphinidae'
- 'Leptodelphis belongs to Kentriodontidae'
- 'Leptophoca belongs to Phocinae'
- 'Liolithax belongs to Kentriodontidae'
- 'Lipotes belongs to Lipotidae'
- 'Lipotidae belongs to Delphinida'
- 'Livyatan belongs to Panphyseteroidea'
- 'Llanocetidae belongs to Mysticeti'
- 'Llanocetus belongs to Llanocetidae'
- 'Lomacetus belongs to Phocoenidae'
- 'Lophocetus belongs to Kentriodontidae'
- 'Loxolithax belongs to Phocoenidae'
- 'Macrokentriodon belongs to Kentriodontidae'
- 'Maiacetus belongs to Protocetidae'
- 'Makaracetus belongs to Protocetidae'
- 'Mammalodon belongs to Mammalodontidae'
- 'Mammalodontidae belongs to Mysticeti'
- 'Masracetus belongs to Basilosauridae'
- 'Matapanui belongs to Eomysticetidae'
- 'Mauicetus belongs to Cetotheriidae'
- 'Megagomphos belongs to Desmatophocidae'
- 'Megaptera (Eschrichtius) was reranked as Eschrichtius and belongs to Eschrichtiidae'
- 'Meherrinia belongs to Kentriodontidae'
- 'Mesocetus belongs to Tranatocetidae'
- 'Messapicetus belongs to Ziphiidae'
- 'Metaxytherium belongs to Dugongidae'
- 'Metopocetus belongs to Cetotheriidae'
- 'Microberardius belongs to Ziphiidae'
- 'Micromysticetus belongs to Eomysticetidae'
- 'Microphocaena belongs to Kentriodontidae'
- 'Miocaperea belongs to Neobalaenidae'
- 'Miodugong belongs to Dugongidae'
- 'Miophocaena belongs to Phocoenidae'
- 'Miosiren belongs to Trichechidae'
- 'Mirocetidae belongs to Odontoceti'
- 'Mirocetus belongs to Mirocetidae'
- 'Mixocetus belongs to Tranatocetidae'
- 'Monachinae belongs to Phocidae'
- 'Monachopsis belongs to Phocinae'
- 'Monodon belongs to Monodontidae'
- 'Monodontidae belongs to Monodontoidae'
- 'Monodontoidae belongs to Delphinida'
- 'Monotherium belongs to Monachinae'
- 'Morawanocetus belongs to Aetiocetidae'
- 'Morenocetus belongs to Balaenidae'
- 'Mycteriacetus belongs to Eurhinodelphinidae'
- 'Mysticeti was reranked as a unranked clade and belongs to Neoceti'
- 'Nalacetus belongs to Pakicetidae'
- 'Nannocetus belongs to Cetotheriidae'
- 'Nanokogia belongs to Kogiidae'
- 'Nanosiren belongs to Dugonginae'
- 'Natchitochia belongs to Protocetidae'
- 'Nazcacetus belongs to Ziphiidae'
- 'Necromites belongs to Phocinae'
- 'Nenga belongs to Ziphiidae'
- 'Neobalaenidae belongs to Plicogulae'
- 'Neoceti belongs to Pelagiceti'
- 'Neoparadoxia belongs to Paleoparadoxiidae'
- 'Neotherium belongs to Odobenidae'
- 'Ninjadelphis belongs to Allodelphinidae'
- 'Ninoziphius belongs to Ziphiidae'
- 'Notiocetus belongs to Balaenopteridae'
- 'Notocetus belongs to Squalodelphinidae'
- 'Notoziphius belongs to Ziphiidae'
- 'Numataphocoena belongs to Phocoenidae'
- 'Ocucajea belongs to Basilosauridae'
- 'Odobaenidae is corrected as Odobenidae and belongs to Pinnipedia'
- 'Odobeninae belongs to Odobenidae'
- 'Odobenocetops belongs to Odobenocetopsidae'
- 'Odobenocetopsidae belongs to Delphinoidea'
- 'Odobenus belongs to Odobeninae'
- 'Odontoceti was reranked as a unranked clade and belongs to Neoceti'
- 'Ontocetus belongs to Odobeninae'
- 'Oriensarctos belongs to Otariidae'
- 'Orycterocetus belongs to Panphyseteroidea'
- 'Otariina was reranked as the family Otariidae and belongs to Pinnipedia'
- 'Otekaikea belongs to Waipatiidae'
- 'Otradnocetus belongs to Cetotheriidae'
- 'Ounalashkastylus belongs to Desmostylia'
- 'Pacificotaria belongs to Pinnipedimorpha'
- 'Pakicetinae was reranked as the family Pakicetidae and belongs to Cetacea'
- 'Pakicetus belongs to Pakicetidae'
- 'Palaeocetus belongs to Balaenopteridae'
- 'Paleoparadoxia belongs to Paleoparadoxiidae'
- 'Paleoparadoxidae is corrected as Paleoparadoxiidae and belongs to Desmostylia'
- 'Palmidophoca belongs to Monachinae'
- 'Panphyseteroidea belongs to Odontoceti'
- 'Papahu belongs to Odontoceti'
- 'Pappocetus belongs to Protocetidae'
- 'Parabalaenoptera belongs to Balaenopteridae'
- 'Paralitherium belongs to Dugongidae'
- 'Parapontoporia belongs to Lipotidae'
- 'Parietobalaena belongs to Cetotheriidae'
- 'Pelagiarctos belongs to Odobenidae'
- 'Pelagiceti belongs to Cetacea'
- 'Pelocetus belongs to Cetotheriidae'
- 'Peripolocetus belongs to Balaenidae'
- 'Pezosiren belongs to Prorastomidae'
- 'Phoca belongs to Phocinae'
- 'Phoca rosmarus is recombined as Odobenus rosmarus'
- 'Phocadae is corrected as Phocidae and belongs to Pinnipedia'
- 'Phocaenina was reranked as the family Phocoenidae and belongs to Monodontoidae'
- 'Phocaenopsis belongs to Eurhinodelphinidae'
- 'Phocanella belongs to Phocinae'
- 'Phocinae belongs to Phocidae'
- 'Physeter belongs to Physeteridae'
- 'Physeteridae belongs to Physeteroidea'
- 'Physeteroidea belongs to Panphyseteroidea'
- 'Physeterula belongs to Physeteridae'
- 'Pinnarctidion belongs to Pinnipedimorpha'
- 'Pinnipedia was reranked as a unranked clade and belongs to Pinnipedimorpha'
- 'Pinnipedimorpha belongs to Arctoidea'
- 'Pinocetus belongs to Cetotheriidae'
- 'Piscobalaena belongs to Cetotheriidae'
- 'Piscocetus belongs to Chaeomysticeti'
- 'Piscolithax belongs to Phocoenidae'
- 'Piscophoca belongs to Monachinae'
- 'Pithanodelphis belongs to Kentriodontidae'
- 'Pithanotaria belongs to Otariidae'
- 'Placoziphius belongs to Panphyseteroidea'
- 'Platalearostrum belongs to Delphinidae'
- 'Platanista belongs to Platanistidae'
- 'Platanistina was reranked as the family Platanistidae and belongs to Platanistoidea'
- 'Platanistoidea belongs to Odontoceti'
- 'Platyosphys belongs to Basilosauridae'
- 'Platyphoca belongs to Phocinae'
- 'Plesiobalaenoptera belongs to Eschrichtiidae'
- 'Plesiocetus belongs to Balaenopteridae'
- 'Plicogulae belongs to Chaeomysticeti'
- 'Pliophoca belongs to Monachinae'
- 'Pliopontos belongs to Pontoporiidae'
- 'Pomatodelphis belongs to Platanistidae'
- 'Pontistes belongs to Pontoporiidae'
- 'Pontobasileus belongs to Protocetidae'
- 'Pontogeneus belongs to Basilosauridae'
- 'Pontolis belongs to Odobenidae'
- 'Pontophoca belongs to Monachinae'
- 'Pontoporia belongs to Pontoporiidae'
- 'Pontoporiidae belongs to Inioidea'
- 'Potamosiren belongs to Trichechidae'
- 'Praekogia belongs to Kogiidae'
- 'Praemegaptera belongs to Balaenopteridae'
- 'Praepusa belongs to Phocinae'
- 'Pristiphoca belongs to Monachinae'
- 'Prohalicore belongs to Dugongidae'
- 'Proneotherium belongs to Odobenidae'
- 'Properiptychus belongs to Monachinae'
- 'Prophoca belongs to Phocinae'
- 'Prorastomidae belongs to Sirenia'
- 'Prorastomus belongs to Prorastomidae'
- 'Prosqualodon belongs to Prosqualodontidae'
- 'Prosqualodontidae belongs to Odontoceti'
- 'Proterozetes belongs to Otariidae'
- 'Protocetidae belongs to Cetacea'
- 'Protocetus belongs to Protocetidae'
- 'Protodobenus belongs to Odobeninae'
- 'Protoglobicephala belongs to Delphinidae'
- 'Protophocaena belongs to Pontoporiidae'
- 'Protororqualus belongs to Balaenopteridae'
- 'Protosiren belongs to Protosirenidae'
- 'Protosirenidae belongs to Sirenia'
- 'Prototaria belongs to Odobenidae'
- 'Pseudotaria belongs to Odobenidae'
- 'Pterocetus belongs to Ziphiidae'
- 'Pteronarctos belongs to Pinnipedimorpha'
- 'Pterophocaena belongs to Phocoenidae'
- 'Qaisracetus belongs to Protocetidae'
- 'Rayanistes belongs to Remingtonocetidae'
- 'Remingtonocetidae belongs to Cetacea'
- 'Remingtonocetus belongs to Remingtonocetidae'
- 'Ribodon belongs to Trichechidae'
- 'Rodhocetus belongs to Protocetidae'
- 'Rosmarus arcticus is recombined as Odobenus rosmarus rosmarus'
- 'Rudicetus belongs to Kentriodontidae'
- 'Rytiodus belongs to Dugonginae'
- 'Saghacetus belongs to Basilosauridae'
- 'Salumiphocaena belongs to Phocoenidae'
- 'Sarmatodelphis belongs to Kentriodontidae'
- 'Saurocetes belongs to Iniidae'
- 'Scaphokogia belongs to Kogiidae'
- 'Schizodelphis belongs to Eurhinodelphinidae'
- 'Semirostrum belongs to Phocoenidae'
- 'Septemtriocetus belongs to Phocoenidae'
- 'Septidelphis belongs to Delphinidae'
- 'Seuku belongs to Desmostylia'
- 'Simocetidae belongs to Odontoceti'
- 'Simocetus belongs to Simocetidae'
- 'Sirenavus belongs to Dugongidae'
- 'Sitsqwayk belongs to Chaeomysticeti'
- 'Sophianacetus belongs to Kentriodontidae'
- 'Squalodelphidae is corrected as Squalodelphinidae and belongs to Platanistoidea'
- 'Squalodon belongs to Squalodontidae'
- 'Squalodontidae belongs to Odontoceti'
- 'Stenasodelphis belongs to Pontoporiidae'
- 'Stromerius belongs to Basilosauridae'
- 'Supayacetus belongs to Basilosauridae'
- 'Synrhina belongs to Odontoceti'
- 'Tagicetus belongs to Kentriodontidae'
- 'Takracetus belongs to Protocetidae'
- 'Thalassocetus belongs to Physeteridae'
- 'Thalassoleon belongs to Otariidae'
- 'Thalassotherii belongs to Balaenomorpha'
- 'Thinocetus belongs to Cetotheriidae'
- 'Tiphyocetus belongs to Cetotheriidae'
- 'Titanocetus belongs to Cetotheriidae'
- 'Togocetus belongs to Protocetidae'
- 'Tohoraata belongs to Eomysticetidae'
- 'Tokarahia belongs to Eomysticetidae'
- 'Tranatocetidae belongs to Thalassotherii'
- 'Tranatocetus belongs to Tranatocetidae'
- 'Trichechus belongs to Trichechidae'
- 'Trichechus divergens is recombined as Odobenus rosmarus divergens'
- 'Trichecidae is corrected as Trichechidae and belongs to Sirenia'
- 'Tusciziphius belongs to Ziphiidae'
- 'Uranocetus belongs to Cetotheriidae'
- 'Valenictus belongs to Odobeninae'
- 'Vanbreenia belongs to Eurhinodelphinidae'
- 'Vanderhoofius belongs to Desmostylia'
- 'Waharoa belongs to Eomysticetidae'
- 'Waipatia belongs to Waipatiidae'
- 'Whakakai belongs to Eomysticetidae'
- 'Willungacetus belongs to Aetiocetidae'
- 'Xenorophidae belongs to Odontoceti'
- 'Xenorophus belongs to Xenorophidae'
- 'Xenosiren belongs to Dugonginae'
- 'Xhosacetus belongs to Ziphiidae'
- 'Xiphiacetus belongs to Eurhinodelphinidae'
- 'Yamatocetus belongs to Eomysticetidae'
- 'Zarhachis belongs to Platanistidae'
- 'Zarhinocetus belongs to Allodelphinidae'
- 'Ziphiidae belongs to Synrhina'
- 'Ziphiodelphis belongs to Eurhinodelphinidae'
- 'Ziphirostrum belongs to Ziphiidae'
- 'Zygiocetus belongs to Cetotheriidae'
- 'Zygophyseter belongs to Panphyseteroidea'
- 'Zygorhiza belongs to Basilosauridae'