Biology:List of plesiosaur genera

Short description: None

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 177 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 Images Abyssosaurus Berezin 2011 Valid Early Cretaceous Russia Had a uniquely short, triangular skull with extremely large eye sockets. Shows potential adaptations for specialized deep-diving lifestyle 200px Acostasaurus Gómez-Pérez & Noè 2017 Valid Early Cretaceous Colombia Noted for its unusually caniniform dentition compared to other pliosaurids 200px Albertonectes Kubo et al. 2012 Valid Late Cretaceous Canada Had the longest neck of any known plesiosaur, made up of seventy-six vertebrae 200px Alexandronectes Otero et al. 2016 Valid Late Cretaceous New Zealand The first aristonectine from which a stapes is known 200px Alexeyisaurus Sennikov & Arkhangelsky 2010 Dubious Late Triassic Russia Although originally described as an elasmosaurid plesiosaur, it was suggested to be an undiagnostic sauropterygian taxon by subsequent analyses Alzadasaurus Welles & Bump 1949 Jr. synonym N/A N/A Junior synonym of Styxosaurus Anguanax Cau & Fanti 2015 Valid Late Jurassic Italy Several features of its skull would indicate a diet of soft or small-bodied prey 200px Anningasaura Vincent & Benson 2012 Valid Early Jurassic United Kingdom Known from a partial skeleton belonging to a juvenile animal 200px Apatomerus Williston 1903 Dubious? Early Cretaceous United States Originally identified as a crocodilian and later reinterpreted as a pterosaur, although it may very likely be a plesiosaur Aphrosaurus Welles 1943 Valid Late Cretaceous United States Distinguished by the presence of a deepened ventral notch along the centra of its cervical vertebrae 200px Apractocleidus Smellie 1915 Jr. synonym N/A N/A Junior synonym of Cryptoclidus Aptychodon von Reuss 1855 Valid Late Cretaceous Czech Republic Some studies suggest this genus may be a potential junior synonym of Polyptychodon 200px Archaeonectrus Novozhilov 1964 Valid Early Jurassic United Kingdom Originally mistakenly believed to be a species of Plesiosaurus 200px Argentinonectes Novas et al. 2026 Valid Late Cretaceous Argentina Several shark teeth were found in association with the holotype 200px Aristonectes Cabrera 1941 Valid Late Cretaceous Antarctica Argentina Chile This genus would have migrated regularly between Patagonia and Antarctica as implied by its fossil record 200px Arminisaurus Sachs & Kear 2017 Valid Early Jurassic Germany Shares some features of its skeleton with leptocleidian plesiosauroids 200px Attenborosaurus Bakker 1993 Valid Early Jurassic United Kingdom Named in honor of British broadcaster and naturalist David Attenborough 200px Atychodracon Smith 2015 Valid Late Triassic to Early Jurassic United Kingdom Has been assigned to four different genera before its formal description 200px Avalonnectes Benson, Evans & Druckenmiller 2012 Valid Early Jurassic United Kingdom One of the oldest plesiosaurs known to date 200px Bathyspondylus Delair 1982 Valid Late Jurassic United Kingdom Possesses an unusual mix of pliosauroid and plesiosauroid features 200px Bishanopliosaurus Dong 1980 Valid Early Jurassic to Middle Jurassic China Could be distinguished by the bifurcated ribs of its sacrum 200px Borealonectes Sato & Wu 2008 Valid Middle Jurassic Canada One of the few North American plesiosaurs that lived during the Jurassic Boyacasaurus Benavides-Cabra et al. 2025 Valid Early Cretaceous Colombia Known from two specimens found in association with ammonites Brachauchenius Williston 1903 Valid Late Cretaceous Morocco United States Several pliosaurid specimens of same age had been referred to this genus, although they were either renamed as new taxa or considered dubious 200px Brancasaurus Wegner 1914 Valid Early Cretaceous Germany Its cervical vertebrae are noted for having shark fin-shaped neural spines 200px Brimosaurus Leidy 1854 Dubious Late Cretaceous United States May be synonymous with Cimoliasaurus Callawayasaurus Carpenter 1999 Valid Early Cretaceous Colombia Has no pectoral bars, a trait shared with Terminonatator 200px Cardiocorax Araújo et al. 2015 Valid Late Cretaceous Angola The morphology of its scapula suggests a relatively unique swimming style for this genus 200px Ceraunosaurus Thurmond 1968 Jr. synonym N/A N/A Junior synonym of Trinacromerum Chubutinectes O'Gorman et al. 2023 Valid Late Cretaceous Argentina Larger than the contemporary Kawanectes due to its marine habitat Cimoliasaurus Leidy 1851 Valid Late Cretaceous United States Discovered in sediments that superficially resemble the chalk deposits found in the Western Interior Seaway 200px Colymbosaurus Seeley 1874 Valid Middle Jurassic to Late Jurassic Norway United Kingdom The holotype humerus was originally misidentified as a femur 200px Crymocetus Cope 1869 Dubious Late Cretaceous United Kingdom Today seen as an indeterminate plesiosaur. Only known from a single vertebra 200px Cryonectes Vincent, Bardet & Mattioli 2012 Valid Early Jurassic France Possessed a relatively elongated snout 200px Cryptoclidus Seeley 1892 Valid Middle Jurassic to Late Jurassic United Kingdom Would have preyed on small, soft-bodied animals as indicated by the delicate build of its skull and teeth 200px Discosaurus Leidy 1851 Valid Late Cretaceous United States Has been argued to be the same taxon as Elasmosaurus 200px Djupedalia Knutsen, Druckenmiller & Hurum 2012 Valid Late Jurassic Norway Named after former Minister of Education and Research Øystein Djupedal 200px Dolichorhynchops Williston 1902 Valid Late Cretaceous Canada United States Described two years after its discovery 200px Dravidosaurus Yadagiri & Ayyasami 1979 Dubious Late Cretaceous India Suggested to be either an ornithischian (potentially stegosaurian) dinosaur or a plesiosaur Eardasaurus Ketchum & Benson 2022 Valid Middle Jurassic United Kingdom Had prominent enamel ridges in its teeth, which would indicate a diet of large prey 200px Edgarosaurus Druckenmiller 2002 Valid Early Cretaceous United States One of the first polycotylids to become native to the Western Interior Seaway 200px Eiectus Noè & Gómez-Pérez 2021 Valid? Early Cretaceous Australia Potentially synonymous with Kronosaurus Elasmosaurus Cope 1868 Valid Late Cretaceous United States Originally erroneously reconstructed with its skull placed at the end of its tail 200px Embaphias Cope 1894 Dubious Late Cretaceous United States Based on three cervical vertebrae Eoplesiosaurus Benson, Evans & Druckenmiller 2012 Valid Early Jurassic United Kingdom May have been the basalmost known member of the Plesiosauroidea 200px Eopolycotylus Albright et al. 2007 Valid Late Cretaceous United States Known from a single partial skeleton 200px Eretmosaurus Seeley 1874 Valid Early Jurassic to Middle Jurassic Russia United Kingdom Two species are known 200px Eromangasaurus Kear 2005 Valid Early Cretaceous Australia The holotype skull is almost complete although badly crushed 200px Eurycleidus Andrews 1922 Valid Early Jurassic United Kingdom May have made a powerful forward stroke for fast swimming as suggested by its relatively large shoulder bones Eurysaurus Gaudry 1878 Valid Early Jurassic France Formerly misidentified as a nothosaur Fluvionectes Campbell et al. 2021 Valid Late Cretaceous Canada The holotype specimen may have died in a log jam as suggested by the pieces of coalified wood found alongside it 200px Franconiasaurus Sachs, Eggmaier & Madzia 2024 Valid Early Jurassic Germany Its cervical and dorsal vertebrae possessed short neural spines 200px Fresnosaurus Welles 1943 Valid Late Cretaceous United States Coexisted with at least three other plesiosaurs 200px Futabasaurus Sato, Hasegawa & Manabe 2006 Valid Late Cretaceous Japan Most of its bones preserve bite marks caused by Cretalamna, indicating it would have been scavenged or hunted by the shark 200px Gallardosaurus Gasparini 2009 Valid Late Jurassic Cuba The only known individual was discovered in a concretion in dark shale 200px "Georgia" Otschev 1976 Preoccupied N/A N/A Preoccupied by a genus of snake, later renamed Georgiasaurus Georgiasaurus Otschev 1977 Valid Late Cretaceous Russia The holotype skeleton was damaged during preparation of the quarry stone 200px Gondwananectes Otero et al. 2026 Valid Middle Jurassic Chile May be the sister taxon to the Cryptoclidia 200px Goniosaurus Meyer 1860 Valid Late Cretaceous Netherlands The striations of its tooth meet each other under an angle pointing to the root instead of the apex Gronausaurus Hampe 2013 Jr. synonym N/A N/A Junior synonym of Brancasaurus Hastanectes Benson et al. 2012 Valid Early Cretaceous United Kingdom Originally named as a species of Cimoliasaurus 200px Hauffiosaurus O'Keefe 2001 Valid Early Jurassic Germany United Kingdom The holotype specimen is preserved lying on its back 200px Hydralmosaurus Welles 1943 Jr. synonym N/A N/A Junior synonym of Styxosaurus Hydrorion Großmann 2007 Valid Early Jurassic Germany Several individuals are known 200px Hydrotherosaurus Welles 1943 Valid Late Cretaceous United States Multiple vertebrae were the first remains to be found. More bones had been unearthed afterwards 200px Ischyrodon von Meyer 1838 Dubious Middle Jurassic Switzerland Has been considered a junior synonym of Liopleurodon, but a 2022 revision found some differences that would make it separate from that genus 200px Jucha Fischer et al. 2020 Valid Early Cretaceous Russia One of the earliest known confirmed elasmosaurids 200px Kaiwhekea Cruickshank & Fordyce 2002 Valid Late Cretaceous New Zealand Preserved inside a large, roughly 6.5 m (21 ft) long concretion 200px Kawanectes O'Gorman 2016 Valid Late Cretaceous Argentina Previously identified as a species of Trinacromerum 200px Kimmerosaurus Brown 1981 Valid Late Jurassic Norway? United Kingdom Its skull was overall similar to that of the related Cryptoclidus but much broader 200px Kronosaurus Longman 1924 Valid Early Cretaceous Australia One of the largest pliosaurids ever identified, likely the apex predator of its environment 200px Lagenanectes Sachs, Hornung & Kear 2017 Valid Early Cretaceous Germany One of the most well-preserved plesiosaurs known from the Early Cretaceous of Europe 200px Leivanectes Páramo-Fonseca et al. 2019 Valid Early Cretaceous Colombia Differs from the contemporary Callawayasaurus, hence its classification as a separate genus Leptocleidus Andrews 1922 Valid Early Cretaceous Australia South Africa United Kingdom Like other members of its family and unlike most other plesiosaurs, it inhabited freshwater environments 200px Leurospondylus Brown 1913 Valid Late Cretaceous Canada Its exact taxonomic placement is uncertain 200px Libonectes Carpenter 1997 Valid Late Cretaceous Morocco United States Originally referred to as a species of Elasmosaurus, but it was named as a distinct genus due to morphological differences 200px Lindwurmia Vincent & Storrs 2019 Valid Early Jurassic Germany Possessed five pairs of premaxillary teeth 200px Liopleurodon Sauvage 1873 Valid Middle Jurassic to Late Jurassic France Germany Mexico United Kingdom Several analyses suggest that this genus may have been an ambush predator 200px Lorrainosaurus Sachs et al. 2023 Valid Middle Jurassic France Originally assigned to Simolestes but it has been found to be more derived 200px Luetkesaurus Kiprijanoff 1883 Dubious Late Cretaceous Russia No species name has ever been assigned Luskhan Fischer et al. 2017 Valid Early Cretaceous Russia Unlike other pliosaurids, it had a slender snout, small teeth, and short tooth rows, convergent with polycotylids 200px Lusonectes Smith, Araújo & Mateus 2012 Valid Early Jurassic Portugal The first plesiosaur named from Portugal 200px Macroplata Swinton 1930 Valid Early Jurassic United Kingdom Its neck is comparatively longer than its head 200px Makhaira Fischer et al. 2015 Valid Early Cretaceous Russia Unusually, its teeth were triangular in cross-section 200px Manemergus Buchy et al. 2005 Valid Late Cretaceous Morocco May have been contemporaneous with Thililua 200px Marambionectes O'Gorman et al. 2024 Valid Late Cretaceous Antarctica Closely allied to the aristonectines 200px Maresaurus Gasparini 1997 Valid Middle Jurassic Argentina The first plesiosaur identified from the Los Molles Formation 200px Marmornectes Ketchum & Benson 2011 Valid Middle Jurassic United Kingdom Would have been very similar to Peloneustes Martinectes Clark, O'Keefe & Slack 2023 Valid Late Cretaceous Russia? United States Initially named as species of Trinacromerum and then assigned to Dolichorhynchops until its reclassification as a new genus in 2023 200px Mauisaurus Hector 1874 Dubious Late Cretaceous New Zealand Several specimens had been referred to this genus, but a 2017 review restricts it only to the lectotype 200px Mauriciosaurus Frey et al. 2017 Valid Late Cretaceous Mexico Similarly to Cryptoclidus, it is noted for the unusual arrangement of gastralia 200px Megacephalosaurus Schumacher et al. 2013 Valid Late Cretaceous United States One of the last known pliosaurids prior to their extinction 200px Megalneusaurus Knight 1898 Valid Late Jurassic United States One specimen preserves stomach contents, including cephalopods and fish 200px Meyerasaurus Smith & Vincent 2010 Valid Early Jurassic Germany Represented by a complete, articulated skeleton 200px Microcleidus Watson 1909 Valid Early Jurassic France Germany Luxembourg United Kingdom Possessed at least forty vertebrae in its neck 200px Monquirasaurus Noè & Gómez-Pérez 2021 Valid Early Cretaceous Colombia Originally known as a South American species of Kronosaurus. Very large for a pliosaurid 200px Morenosaurus Welles 1943 Valid Late Cretaceous United States The only described specimen is nearly complete, missing only the skull and some parts of the neck and paddles 200px Morturneria Chatterjee & Creisler 1994 Valid Late Cretaceous Antarctica Once considered to be a juvenile Aristonectes, but a 2017 study found it to be distinct enough to warrant recognition as separate 200px Muraenosaurus Seeley 1874 Valid Middle Jurassic United Kingdom May have possessed an increased muscle attachment towards its neck as indicated by its elongated cervical vertebrae with broad neural spines 200px Nakonanectes Serratos et al. 2017 Valid Late Cretaceous United States Its overall morphology was exceptionally similar to that of aristonectines despite being less derived 200px Nichollssaura Druckenmiller & Russell 2009 Valid Early Cretaceous Canada Fills a temporal gap of approximately 40 million years in the fossil record of North American plesiosaurs 200px "Nichollsia" Druckenmiller & Russell 2008 Preoccupied N/A N/A Preoccupied by a genus of isopod, renamed Nichollssaura Occitanosaurus Bardet et al. 1999 Jr. synonym N/A N/A Junior synonym of Microcleidus Ogmodirus Williston & Moodie 1913 Dubious Late Cretaceous United States May be an elasmosaurid 200px Oligosimus Leidy 1872 Jr. synonym N/A N/A Junior synonym of Cimoliasaurus Opallionectes Kear 2006 Valid Early Cretaceous Australia Hypothesized to live on a cold habitat 200px Ophthalmothule Roberts et al. 2020 Valid Late Jurassic to Early Cretaceous Norway May have possibly hunted at night and/or in the bathypelagic zone as suggested by its relatively large eye sockets and features similar to those of Abyssosaurus 200px Orophosaurus Cope 1851 Dubious Late Cretaceous United States Named based only on portions of three neck vertebrae Pachycostasaurus Cruickshank et al. 1996 Valid Middle Jurassic United Kingdom Its skeleton bears several unique features in most of the bones 200px Pahasapasaurus Schumacher 2007 Valid Late Cretaceous United States Distinguishable by characters of its epipodial and palate bones 200px "Palmula" Albright et al. 2007 Preoccupied N/A N/A Preoccupied by a genus of foraminifer, renamed Palmulasaurus Palmulasaurus Albright et al. 2007 Valid Late Cretaceous United States Shared its environment with three other polycotylids 200px Pantosaurus Marsh 1893 Valid Late Jurassic United States One fossil preserves a partially digested ichthyosaur embryo within its stomach cavity 200px Peloneustes Lydekker 1889 Valid Middle Jurassic United Kingdom Multiple specimens are known, including fairly complete material, which make it one of the most well-known pliosaurids 200px Peyerus Stromer 1935 Jr. synonym N/A N/A Junior synonym of Leptocleidus Picrocleidus Andrews 1910 Valid Middle Jurassic United Kingdom Previously synonymized with the coeval Muraenosaurus, but this has been cast into doubt 200px Piptomerus Cope 1887 Jr. synonym N/A N/A Junior synonym of Cimoliasaurus Piratosaurus Leidy 1865 Dubious Late Cretaceous Canada Solely known from a single tooth which may have come from a polycotylid 200px Plesioelasmosaurus Schumacher & Everhart 2022 Valid Late Cretaceous United States Would have been relatively basal for an elasmosaurid 200px Plesionectes Sachs & Madzia 2025 Valid Early Jurassic Germany Preserved patches of soft tissue impressions that may indicate a dark coloration for this taxon 200px Plesiopharos Puértolas-Pascual et al. 2021 Valid Early Jurassic Portugal The holotype was discovered next to a lighthouse 200px Plesiopleurodon Carpenter 1996 Valid Late Cretaceous United States Initially believed to be a member of the Pliosauroidea 200px Plesiopterys O'Keefe 2004 Valid Early Jurassic Germany Displays an unusual combination of primitive and derived traits 200px Plesiosaurus De la Beche & Conybeare 1821 Valid Early Jurassic United Kingdom The first plesiosaur genus scientifically named and described. May be the most commonly found member in the Lias Group 200px Pliosaurus Owen 1841 Valid Late Jurassic to Early Cretaceous Norway Russia Ukraine United Kingdom One of the largest known pliosaurids. The second specimen of P. funkei has been nicknamed "Predator X" 200px Polycotylus Cope 1869 Valid Late Cretaceous Russia United States One particular specimen preserves a fetus inside of it, suggesting it gave live birth 200px Polyptychodon Owen 1841 Dubious Late Cretaceous Argentina? France? United Kingdom The sauropod dinosaur Dinodocus had been mistakenly attributed to this genus 200px "Raptocleidus" Evans 2012 Nomen nudum Early Jurassic United Kingdom Two species have been named, albeit informally Rhaeticosaurus Wintrich et al. 2017 Valid Late Triassic Germany One of the few plesiosaurs known from the Triassic Rhomaleosaurus Seeley 1874 Valid Early Jurassic United Kingdom One of the largest early predatory marine reptiles. Four species are known 200px Sachicasaurus Páramo-Fonseca et al. 2018 Valid Early Cretaceous Colombia One of the largest and most completely known pliosaurids yet described 200px Scalamagnus Clark, O'Keefe & Slack 2023 Valid Late Cretaceous United States Once believed to be a species of Dolichorhynchops 200px Scanisaurus Persson 1959 Dubious Late Cretaceous Russia Sweden Although it is now considered dubious, this genus continues to be used in practice 200px Seeleyosaurus White 1940 Valid Early Jurassic Germany Russia? Remains originally identified as Plesiosaurus 200px Serpentisuchops Persons, Street & Kelley 2022 Valid Late Cretaceous United States Had an exceptionally long neck, a unique trait among polycotylids 200px Simolestes Andrews 1909 Valid Middle Jurassic to Late Jurassic India? United Kingdom Possessed an unusually short, high skull 200px Sinopliosaurus Young 1944 Dubious Early Cretaceous China Based only on a tooth and three vertebrae Spitrasaurus Knutsen, Druckenmiller & Hurum 2012 Valid Late Jurassic Norway United Kingdom? Two species have been named 200px Spondylosaurus Fischer 1845 Jr. synonym N/A N/A Junior synonym of Pliosaurus Stenorhynchosaurus Páramo-Fonseca et al. 2016 Valid Early Cretaceous Colombia Originally identified as a specimen of Brachauchenius 200px "Stereosaurus" Seeley 1869 Nomen nudum Late Cretaceous United Kingdom An informally named plesiosaur Sthenarosaurus Watson 1909 Valid Early Jurassic United Kingdom Its pelvis was relatively broad and strong 200px Stratesaurus Benson, Evans & Druckenmiller 2012 Valid Early Jurassic United Kingdom Possibly the basalmost known rhomaleosaurid 200px Stretosaurus Tarlo 1959 Jr. synonym N/A N/A Junior synonym of Pliosaurus Strongylokrotaphus Novozhilov 1964 Jr. synonym N/A N/A Junior synonym of Pliosaurus Styxosaurus Welles 1943 Valid Late Cretaceous United States Closely related to Elasmosaurus, but can be differentiated from it based on morphological features 200px Sulcusuchus Gasparini & Spalletti 1990 Valid Late Cretaceous Argentina Originally mistakenly believed to be a pseudosuchian 200px Taphrosaurus Cope 1870 Dubious Late Cretaceous United States Poorly known Tatenectes O'Keefe & Wahl 2003 Valid Late Jurassic United States Its unusual body shape and pachyostotic gastralia would have made it more suitable to turbulence 200px Terminonatator Sato 2003 Valid Late Cretaceous Canada One of the youngest plesiosaurs known from the Western Interior Seaway 200px Thalassiodracon Storrs & Taylor 1996 Valid Late Triassic to Early Jurassic United Kingdom Its maxillae had heterodont dentition 200px Thalassiosaurus Welles 1953 Jr. synonym N/A N/A Junior synonym of Styxosaurus Thalassomedon Welles 1943 Valid Late Cretaceous United States The type specimen has stones preserved in its stomach cavity 200px Thalassonomosaurus Welles 1943 Jr. synonym N/A N/A Junior synonym of Styxosaurus Thaumatodracon Smith & Araújo 2017 Valid Early Jurassic United Kingdom Relatively large for a rhomaleosaurid Thaumatosaurus von Meyer 1841 Jr. synonym N/A N/A The holotype is dubious and not diagnostic, as it can be referred to as an indeterminate pliosauroid. The specimens that were assigned to this genus now belong to different taxa Thililua Bardet, Suberbiola & Jalil 2003 Valid Late Cretaceous Morocco The first polycotylid plesiosaur named from Africa 200px Traskasaura O'Keefe et al. 2025 Valid Late Cretaceous Canada Before its formal scientific description, it has been variously referred to as the "Courtenay elasmosaur", "Puntledge elasmosaur", or "Haslam elasmosaur". Officially recognized as the Provincial Fossil of British Columbia 200px Tremamesacleis White 1940 Jr. synonym N/A N/A Junior synonym of Muraenosaurus Trematospondylus Quenstedt 1858 Dubious Middle Jurassic Germany One of the first described plesiosaurs. Known only from seven large vertebrae Tricleidus Andrews 1909 Valid Middle Jurassic United Kingdom One referred species has been later found to belong to Colymbosaurus 200px Trinacromerum Cragin 1888 Valid Late Cretaceous Canada United States May have preyed on small fish as suggested by its dentition 200px Tuarangisaurus Wiffen, Wiffen & Moisley 1986 Valid Late Cretaceous New Zealand Possesses two features in its skeleton that are otherwise unknown in other elasmosaurids 200px "Turneria" Chatterjee & Small 1989 Preoccupied N/A N/A Preoccupied by a genus of ant, renamed Morturneria Umoonasaurus Kear, Schroeder & Lee 2006 Valid Early Cretaceous Australia Uniquely for a plesiosaur, its skull features three crest-ridges that were likely covered in keratin 200px Unktaheela Clark, O'Keefe & Slack 2023 Valid Late Cretaceous United States The smallest adult polycotylid yet known 200px Uronautes Cope 1876 Dubious Late Cretaceous United States Described as a rhomaleosaurid but its extremely late age casts doubt into this Vectocleidus Benson et al. 2012 Valid Early Cretaceous United Kingdom Previously thought to belong to its relative Leptocleidus 200px Vegasaurus O'Gorman et al. 2015 Valid Late Cretaceous Antarctica May be closely related to Morenosaurus 200px Vinialesaurus Gasparini et al. 2002 Valid Late Jurassic Cuba Originally referred to as a species of Cryptoclidus, but it was distinct enough from that genus to be named as its own taxon 200px Wapuskanectes Druckenmiller & Russell 2006 Valid Early Cretaceous Canada The oldest known elasmosaurid from North America 200px Westphaliasaurus Schwermann & Sander 2011 Valid Early Jurassic Germany Known from an articulated, almost complete skeleton 200px Woolungasaurus Persson 1960 Dubious Early Cretaceous Australia Today considered an indeterminate elasmosaurid 200px Wunyelfia Otero et al. 2021 Valid Late Cretaceous Chile One of the few Patagonian plesiosaurs described from outside Argentina 200px Yuzhoupliosaurus Zhang 1985 Valid Middle Jurassic China Distinguishable by its long coracoids and well-developed clavicles Zarafasaura Vincent et al. 2011 Valid Late Cretaceous Morocco Unlike other elasmosaurids, its skull was unusually short 200px

See also

• Sauropterygia
  • Plesiosaur
• List of dinosaurs
• List of ichthyosaurs
• List of mosasaurs
• List of pterosaurs

References

• Haaramo, Mikko (15 November 2005). "Plesiosauria". Mikko's Phylogeny Archive. http://www.fmnh.helsinki.fi/users/haaramo/Metazoa/Deuterostoma/Chordata/Reptilia/Sauropterygia/Plesiosauria.htm. 
• Smith, Adam Stuart. "Plesiosaur Genera". The Plesiosaur Directory. http://www.plesiosauria.com/genera.html.