# List of plesiosaur genera

This list of plesiosaurs is a comprehensive listing of all genera that have ever been included in the order Plesiosauria, excluding purely vernacular terms. The list includes all commonly accepted genera, but also genera that are now considered invalid, doubtful (nomen dubium), or were not formally published (nomen nudum), as well as junior synonyms of more established names, and genera that are no longer considered plesiosaurs. The list currently includes 172 genera.

## Scope and terminology

There is no official, canonical list of plesiosaur genera but one of the most thorough attempts can be found on the Plesiosauria section of Mikko Haaramo's Phylogeny Archive; also pertinent is the Plesiosaur Genera section at Adam Stuart Smith's Plesiosaur Directory.
Naming conventions and terminology follow the International Code of Zoological Nomenclature. Technical terms used include:
* Junior synonym: A name which describes the same taxon as a previously published name. If two or more genera are formally designated and the type specimens are later assigned to the same genus, the first to be published (in chronological order) is the senior synonym, and all other instances are junior synonyms. Senior synonyms are generally used, except by special decision of the ICZN, but junior synonyms cannot be used again, even if deprecated. Junior synonymy is often subjective, unless the genera described were both based on the same type specimen.
* Nomen nudum (Latin for "naked name"): A name that has appeared in print but has not yet been formally published by the standards of the ICZN. Nomina nuda (the plural form) are invalid, and are therefore not italicized as a proper generic name would be. If the name is later formally published, that name is no longer a nomen nudum and will be italicized on this list. Often, the formally published name will differ from any nomina nuda that describe the same specimen. In this case, these nomina nuda will be deleted from this list in favor of the published name.
* Preoccupied name: A name that is formally published, but which has already been used for another taxon. This second use is invalid (as are all subsequent uses) and the name must be replaced. As preoccupied names are not valid generic names, they will also go unitalicized on this list.
* Nomen dubium (Latin for "dubious name"): A name describing a fossil with no unique diagnostic features. As this can be an extremely subjective and controversial designation, this term is not used on this list.

## The list

| Genus | Authors | Year | Status | Age | Location | Notes |
| Abyssosaurus | Berezin | 2011 | Valid | eK | Europe | |
| Acostasaurus | Gómez-Pérez Noè | 2017 | Valid | eK | South America | |
| Albertonectes | Kubo Mitchell Henderson | 2012 | Valid | lK | North America | |
| Alexandronectes | Otero et al. | 2016 | Valid | lK | Australasia | |
| Alexeyisaurus | Sennikov Arkhangelsky | 2010 | Valid | lT | Europe | |
| "Alzadasaurus" | Welles | 1943 | | | | |
| Anguanax | Cau Fanti | 2015 | Valid | lJ | Europe | |
| Anningasaura | Vincent Benson | 2012 | Valid | eJ | Europe | |
| Apatomerus | Williston | 1903 | Valid | eK | | |
| Aphrosaurus | Welles | 1943 | Valid | lK | | |
| "Apractocleidus" | Smellie | 1916 | Jr. synonym | | | Junior synonym of Cryptoclidus. |
| Aptychodon | Reuss | 1855 | Valid | lK | | |
| Archaeonectrus | Owen | 1865 | Valid | eJ | Europe | |
| Arminisaurus | Sachs Kear | 2018 | Valid | eJ | Europe | |
| Aristonectes | Cabrera | 1941 | Valid | lK | South America, Antarctica | |
| Attenborosaurus | Bakker | 1993 | Valid | eJ | Europe | |
| Atychodracon | Smith | 2015 | Valid | | Europe | |
| Avalonnectes | Benson Evans Druckenmiller | 2012 | Valid | eJ | Europe | |
| Bathyspondylus | Delair | 1982 | Valid | lJ | | |
| Bishanopliosaurus | Dong | 1980 | Valid | eJ | | |
| Bobosaurus | Dalla Vecchia | 2006 | Valid | lT | | |
| Borealonectes | Sato Wu | 1980 | Valid | mJ | | |
| Brachauchenius | Williston | 1903 | Valid | eK to lK | | |
| Brancasaurus | Wegner | 1914 | Valid | eK | | |
| Brimosaurus | Leidy | 1855 | Valid | lK | | |
| Callawayasaurus | Carpenter | 1999 | Valid | eK | | |
| Cardiocorax | Araújo et al. | 2015 | Valid | lK | Africa | |
| Ceraunosaurus | Thurmond | 1968 | Jr. synonym | | | Junior synonym of Trinacromerum. |
| Chubutinectes | O'Gorman et al. | 2023 | Valid | lK | South America | |
| Cimoliasaurus | Leidy | 1851 | Valid | lK | | |
| Colymbosaurus | Seeley | 1874 | Valid | lJ | | |
| Crymocetus | Cope | 1869 | Valid | eK | | |
| Cryonectes | Vincent Bardet Mattioli | 2013 | Valid | eJ | Europe | |
| Cryptoclidus | Seeley | 1892 | Valid | mJ | Europe | |
| Discosaurus | Leidy | 1851 | Valid | | | |
| Djupedalia | Knutsen Druckenmiller Hurum | 2012 | Valid | lJ | Europe | |
| Dolichorhynchops | Williston | 1903 | Valid | | North America | |
| Dravidosaurus | Yadagiri Ayyasami | 1979 | Nomen dubium | lK | Asia | Possibly a stegosaurian dinosaur |
| Eardasaurus | Ketchum Benson | 2022 | Valid | mJ | Europe | |
| Edgarosaurus | Druckenmiller | 2002 | Valid | eK | North America | |
| Eiectus | Noè Gómez-Pérez | 2021 | Valid | eK | Australia | |
| Elasmosaurus | Cope | 1868 | Valid | | North America Asia | |
| Embaphias | Cope | 1894 | Nomen dubium | lK | North America | |
| Eoplesiosaurus | Benson Evans Druckenmiller | 2012 | Valid | eJ | Europe | |
| Eopolycotylus | Albright Gillette Titus | 2007 | Valid | | | |
| Eretmosaurus | Seeley | 1874 | Valid | | | |
| Eromangasaurus | Kear | 2005 | Valid | | | |
| Eurycleidus | Andrews | 1922 | Valid | | | |
| Eurysaurus | Gaudry | 1878 | Valid | | | |
| Fluvionectes | Campbell et al. | 2021 | Valid | lK | North America | |
| Franconiasaurus | Sachs Eggmaier Madzia | 2024 | Valid | eJ | Europe | |
| Fresnosaurus | Welles | 1943 | Valid | | | |
| Futabasaurus | Sato Hasegawa Manabe | 2006 | Valid | lK | Asia | Also a theropod nomen nudum ("Futabasaurus"). |
| Gallardosaurus | Gasparini | 2009 | Valid | | | |
| "Georgia" | Otschev | 1976 | Preoccupied | | | Preoccupied by a genus of mollusk, renamed Georgiasaurus. |
| Georgiasaurus | Otschev | 1978 | Valid | | | |
| Goniosaurus | Meyer | 1860 | Valid | | | |
| Gronausaurus | Hampe | 2013 | Valid | eK | Europe | |
| Hastanectes | Benson et al. | 2012 | Valid | eK | Europe | |
| Hauffiosaurus | O'Keefe | 2001 | Valid | | | |
| Hydralmosaurus | Welles | 1943 | Valid | | | |
| Hydrorion | Grobmann | 2006 | Valid | | | |
| Hydrotherosaurus | Welles | 1943 | Valid | lK | North America | |
| Ischyrodon | von Meyer | 1838 | Jr. synonym | | | Junior synonym of Liopleurodon. |
| Jucha | Fischer et al. | 2020 | Valid | eK | Europe | |
| Kaiwhekea | Cruickshank Fordyce | 2002 | Valid | lJ | Europe | |
| Kawanectes | O'Gorman | 2016 | Valid | lK | South America | |
| Kimmerosaurus | Brown | 1981 | Valid | | | |
| Kronosaurus | Longman | 1924 | Valid | | Australia, South America | |
| Lagenanectes | Sachs Hornung Kear | 2017 | Valid | eK | Europe | |
| Leivanectes | Páramo-Fonseca O'Gorman Gasparini Padilla Parra Ruge | 2019 | Valid | eK | South America | |
| Leptocleidus | Andrews | 1922 | Valid | eK | Europe, Africa, Australia | |
| Leurospondylus | Brown | 1913 | Valid | | | |
| Libonectes | Carpenter | 1997 | Valid | | | |
| Lindwurmia | Vincent Storrs | 2019 | Valid | eJ | Europe | |
| Liopleurodon | Sauvage | 1873 | Valid | | | |
| Lorrainosaurus | Sachs et al. | 2023 | Valid | mJ | Europe | Originally assigned to Simolestes. |
| Luetkesaurus | Kiprijanoff | 1883 | Valid | | | |
| Luskhan | Fischer et al. | 2017 | Valid | eK | Europe | |
| Lusonectes | Smith Araújo Mateus | 2011 | Valid | eJ | Europe | |
| Macroplata | Swinton | 1930 | Valid | eJ | Europe | |
| Makhaira | Fischer et al. | 2015 | Valid | eK | | |
| Manemergus | Buchy Metayer Frey | 2005 | Valid | | | |
| Marambionectes | O'Gorman et al. | 2024 | Valid | lK | Antarctica | |
| Maresaurus | Gasparini | 1997 | Valid | | | |
| Marmornectes | Ketchum Benson | 2011 | Valid | mJ | Europe | |
| Martinectes | Clark O’Keefe Slack | 2024 | Valid | lK | North America | |
| Mauisaurus | Hector | 1874 | Valid | | | |
| Mauriciosaurus | Frey et al. | 2017 | Valid | lK | North America | |
| Megacephalosaurus | Schumacher Carpenter Everhart | 2013 | Valid | lK | North America | |
| Megalneusaurus | Knight | 1898 | Valid | | | |
| Meyerasaurus | Smith Vincent | 2010 | Valid | eJ | Europe | |
| Microcleidus | Watson | 1911 | Valid | eJ | | |
| Monquirasaurus | Noè Gómez-Pérez | 2021 | Valid | eK | South America | |
| Morenosaurus | Welles | 1943 | Valid | | | |
| Morturneria | Chatterjee Creisler | 1994 | Jr. synonym | | | Junior synonym of Aristonectes. |
| Muraenosaurus | Seeley | 1874 | Valid | mJ | Europe | |
| Nakonanectes | Serratos Druckenmiller Benson | 2017 | Valid | lK | North America | |
| Nichollssaura | Druckenmiller Russell | 2009 | Valid | eK | North America | |
| "Nichollsia" | Druckenmiller Russell | 2008 | Preoccupied | | | Preoccupied by a genus of isopod, renamed Nichollssaura. |
| Occitanosaurus | Bardet Fernandez Garcia-Ramos Superbiola Pinuela Ruiz-Omenaca Vincent | 2008 | Valid | | | |
| Ogmodirus | Williston Moodie | 1917 | Valid | | | |
| Oligosimus | Leidy | 1872 | Nomen dubium | lK | North America | |
| Opallionectes | Kear | 2006 | Valid | | | |
| Ophthalmothule | Roberts et al. | 2020 | Valid | lJ-eK | Europe | |
| Orophosaurus | Cope | 1851 | Valid | | | |
| Pachycostasaurus | Cruickshank Martill | 1996 | Valid | | | |
| Pahasapasaurus | Schumacher | 2007 | Valid | | | |
| "Palmula" | Albright Gillette Titus | 2007 | Preoccupied | | | Preoccupied by a genus of foraminifer, renamed Palmulasaurus. |
| Palmulasaurus | Albright Gillete Titus | 2007 | Valid | | | |
| Pantosaurus | Marsh | 1893 | Valid | | | |
| Peloneustes | Lydekker | 1889 | Valid | mJ | Europe | |
| Peyerus | Stromer | 1935 | Jr. synonym | | | Junior synonym of Leptocleidus. |
| Picrocleidus | Andrews | 1909 | Jr. synonym | | | Junior synonym of Muraenosaurus. |
| Piptomerus | Cope | 1887 | Valid | | | |
| Piratosaurus | Leidy | 1865 | Valid | | | |
| Plesioelasmosaurus | Schumacher Everhart | 2022 | Valid | lK | North America | |
| Plesiopharos | Puértolas-Pascual et al. | 2021 | Valid | eJ | Europe |
| Plesiopleurodon | Carpenter | 1996 | Valid | | | |
| Plesiopterys | O'Keefe | 2004 | Valid | | | |
| Plesiosaurus | Conybeare | 1821 | Valid | eJ | Europe | |
| Pliosaurus | Owen | 1841 | Valid | | | |
| Polycotylus | Cope | 1869 | Valid | | | |
| Polyptychodon | Owen | 1841 | Valid | | | |
| Rhaeticosaurus | Wintrich et al. | 2017 | Valid | lT | Europe | |
| Rhomaleosaurus | Seeley | 1871 | Valid | eJ | Europe | |
| Sachicasaurus | Páramo-Fonseca Benavides-Cabra Gutiérrez | 2018 | Valid | eK | South America | |
| Scalamagnus | Clark O’Keefe Slack | 2024 | Valid | lK | North America | |
| Scanisaurus | Persson | 1959 | Valid | | | |
| Seeleyosaurus | White | 1940 | Valid | eJ | Europe | |
| Serpentisuchops | Persons Street Kelley | 2022 | Valid | lK | North America | |
| Simolestes | Andrews | 1909 | Valid | | | |
| Sinopliosaurus | Young | 1944 | Valid | eK | | |
| Spitrasaurus | Knutsen Druckenmiller Hurum | 2012 | Valid | lJ | Europe | |
| Spondylosaurus | Fisher | 1845 | Jr. synonym | | | Junior synonym of Pliosaurus. |
| Stratesaurus | Benson Evans Druckenmiller | 2012 | Valid | eJ | Europe | |
| Sulcusuchus | Gasparini Spalletti | 1992 | Valid | lK | South America | |
| Stenorhynchosaurus | Páramo et al. | 2016 | Valid | eK | South America | |
| Stereosaurus | Seeley | 1869 | Valid | | | |
| Sthenarosaurus | Watson | 1911 | Valid | eJ | | |
| "Stretosaurus" | Tarlo | 1959 | InValid | | | Type specimen is undiagnostic and should be assigned to Thalassophonea indeterminate. |
| Strongylokrotaphus | Novozhilov | 1964 | Jr. synonym | | | Junior synonym of Pliosaurus. |
| Styxosaurus | Welles | 1952 | Valid | lK | North America | |
| Taphrosaurus | Cope | 1870 | Valid | lK | |
| "Tatenectes" | Knight | 1900 | Valid | | | |
| Terminonatator | Sato | 2003 | Valid | lK | | |
| Thalassiodracon | Storrs Taylor | 1996 | Valid | lT-eJ | Europe | |
| Thalassiosaurus | Welles | 1953 | Jr. synonym | | | Junior synonym of Styxosaurus. |
| Thalassomedon | Welles | 1943 | Valid | lK | North America | |
| Thalassonomosaurus | Welles | 1943 | Jr. synonym | | | Junior synonym of Styxosaurus. |
| Thaumatodracon | Smith Araújo | 2017 | Valid | lK | Europe | |
| "Thaumatosaurus" | Meyer | 1841 | InValid | | | Holotype is not diagnostic and can be referred to Pliosauroidea indet at best. |
| Thililua | Bardet Suberbiola Jalil | 2003 | Valid | lK | | |
| "Tremamesacleis" | White | 1940 | Jr. synonym | | | Junior synonym of Muraenosaurus. |
| Trematospondylus | Quenstedt | 1858 | Nomen dubium | mJ | Europe | |
| Tricleidus | Andrews | 1909 | Valid | | | |
| Trinacromerum | Cragin | 1888 | Valid | lK | North America | |
| Tuarangisaurus | Wiffen Moisley | 1986 | Valid | lK | | |
| "Turneria" | Chatterjee Small | 1989 | Preoccupied | | | Preoccupied by a genus of ant, renamed Morturneria which is now recognised as a junior synonym of Aristonectes. |
| Umoonasaurus | Kear Schroeder Lee | 2006 | Valid | eK | Australia | |
| Unktaheela | Clark O’Keefe Slack | 2024 | Valid | lK | North America | |
| Uronautes | Cope | 1870 | Valid | lK | | |
| Vectocleidus | Benson et al. | 2012 | Valid | eK | Europe | |
| Vegasaurus | O'Gorman Salgado Olivero Marenssi | 2015 | Valid | lK | Antarctica | |
| Vinialesaurus | Gasparini Bardet Vinent Iturralde | 2002 | Valid | lJ | | |
| Westphaliasaurus | Schwermann Sander | 2011 | Valid | eJ | Europe | |
| Woolungasaurus | Persson | 1960 | Valid | eK | | |
| Wunyelfia | Otero Soto-Acuña | 2020 | Valid | lK | South America | |
| Yuzhoupliosaurus | Zhang | 1985 | Valid | mJ | | |
| "Zahrisaurus" | Malkani | 2019 | Nomen nudum | lK | Asia | |
| Zarafasaura | Vincent Pereda-Suberbiola Bouya Amaghzaz Meslouh | 2011 | Valid | lK | Africa | |
* Aristonectes
* Attenborosaurus
* Atychodracon
* Cryptoclidus
* Dolichorhynchops
* Edgarosaurus
* Elasmosaurus
* Franconiasaurus
* Futabasaurus
* Hydrotherosaurus
* Kaiwhekea
* Kronosaurus
* Leptocleidus
* Liopleurodon
* Macroplata
* Martinectes
* Microcleidus
* Muraenosaurus
* Nichollssaura
* Peloneustes
* Plesiopleurodon
* Plesiosaurus
* Pliosaurus
* Polyptychodon
* Rhomaleosaurus
* Scalamagnus
* Seeleyosaurus
* Simolestes
* Styxosaurus
* Thalassiodracon
* Thalassomedon
* Trinacromerum
* Umoonasaurus