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Contact

About the author
Email: plesiosauria@gmail.com
Follow: @adamstuartsmith

Higher taxa

  • Sauropterygia
  • Eosauropterygia
  • Eusauropterygia
  • Pachypleurosauria
  • Nothosauria
  • Pistosauroidea
  • Pistosauria
  • Plesiosauria
  • Pliosauroidea
  • Plesiosauroidea

Families

  • Aristonectidae
  • Brachauchenidae
  • Cimoliasauridae
  • Cryptoclididae
  • Elasmosauridae
  • Leptocleididae
  • Microcleididae
  • Plesiosauridae
  • Pliosauridae
  • Polycotylidae
  • Rhomaleosauridae

Genera

The genera section is under construction, active pages are indicated by an asterisk

  • A
  • Albertonectes
  • Alexeyisaurus
  • Alzadosaurus
  • Anningasaura
  • Aphrosaurus
  • * 'Apractocleidus'
  • * Archaeonectrus
  • * Aristonectes
  • * Attenborosaurus
  • Augustasaurus
  • Avalonnectes
  • B
  • Bathyspondylus
  • Bishanopliosaurus
  • * Bobosaurus
  • Borealonectes
  • Brachauchenius
  • * Brancasaurus
  • C
  • Callawayasaurus
  • 'Cimoliasaurus'
  • Colymbosaurus
  • * Cryptoclidus
  • D
  • Dolichorhynchops
  • E
  • * Edgarosaurus
  • * Elasmosaurus
  • Eoplesiosaurus
  • Eopolycotylus
  • * Eretmosaurus
  • Eromangasaurus
  • Eurycleidus
  • F
  • Fresnosaurus
  • Futabasaurus
  • G
  • Gallardosaurus
  • Georgiasaurus
  • H
  • Hauffiosaurus
  • Hydralmosaurus
  • Hydrorion
  • Hydrotherosaurus
  • I
  • J
  • K
  • * Kaiwhekea
  • * Kimmerosaurus
  • * Kronosaurus
  • L
  • * Leptocleidus
  • Leurospondylus
  • * Libonectes
  • * Liopleurodon
  • Lusonectes
  • M
  • * Macroplata
  • Manemergus
  • * Maresaurus
  • Marmornectes
  • Mauisaurus
  • Megalneusaurus
  • * Meyerasaurus
  • Microcleidus
  • Morenosaurus
  • * 'Morturneria'
  • Muraenosaurus
  • N
  • Nichollssaura
  • O
  • * Occitanosaurus
  • 'Ogmodirus'
  • Opallionectes
  • P
  • * Pachycostasaurus
  • Pahasapasaurus
  • Palmulasaurus
  • Pantosaurus
  • * Peloneustes
  • Pistosaurus
  • Plesiopleurodon
  • Plesiopterys
  • * Plesiosaurus
  • Pliosaurus
  • Polycotylus
  • Polyptychodon
  • Q
  • R
  • * Rhomaleosaurus
  • S
  • Seeleyosaurus
  • Scanisaurus
  • * Simolestes
  • Sthenarosaurus
  • Stratesaurus
  • 'Stretosaurus'
  • Strongylokrotaphus
  • Styxosaurus
  • Sulcusuchus
  • T
  • Tatenectes
  • Terminonatator
  • * Thalassiodracon
  • * Thalassomedon
  • 'Thaumatosaurus'
  • *Thililua
  • Trememesacleis'
  • *Tricleidus
  • Trinacromerum
  • Tuarangisaurus
  • U
  • Umoonasaurus
  • V
  • Vinialesaurus
  • W
  • Wapuskanectes
  • Westphaliasaurus
  • Woolungasaurus
  • X
  • Y
  • Yuzhoupliosaurus
  • Z
  • Zarafasaura

Stratigraphy

Sauropterygians have the longest stratigraphic range of any group of Mesozoic marine reptiles. Basal sauropterygians occur throughout the Triassic and material identified as possible plesiosaurs occurs in Middle Triassic deposits (Benton, 1993). However, the oldest diagnostic plesiosaurs do not occur until the uppermost Triassic (Taylor and Cruickshank, 1993b; Storrs, 1994, 1997).

Stratigraphic ranges of the main groups of Mesozoic marine reptiles. The sauropterygian fossil record spans throughout the whole of the Triassic, Jurassic, and Cretaceous periods. Ichthyosaurs became extinct during the Cretaceous Period. Squamates (represented by mosasaurs) originated late in the Mesozoic, during the Cretaceous Period. Modified from Benson et. al. (2009)

The plesiosaur lineage reached a worldwide distribution during the early Jurassic Period and plesiosaurs achieved their maximum diversity during the Late Jurassic (Sullivan, 1987). They persisted successfully to the end of the Cretaceous Period - their fossil record comes to an end at the K-T boundary. Plesiosaur vertebrae of putative Palaeocene age were wrongly dated (Lucas and Reynolds, 1993).

Geological time scale

Chronostratigraphy is the division of the rock record into discrete units of time (as opposed to discrete units, or formations, of rocks - lithostratigraphy). The Mesozoic Era is divided into several systems, which are themselves subdivided into series, which are divided into stages. These units of rock correspond to geochronological units of time (Periods, Epochs and ages, respectively.) These terms are used throughout this site so the table below provides a summary of Mesozoic chronostratigraphy/geochronology for reference.

Cretaceous

Upper

Maastrichtian

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(Keuper (Mid Ladinian - End Carnian). Muschelkalk (mid Anisian - mid Ladinian). Buntsandstein (Scythian - mid Anisian))

Campanian

Santonian

Coniacian

Turonian

Cenomanian

Lower

Albian

Aptian

Barremian

Hauterivian

Valanginian

Berriasian

Jurassic

Upper

Tithonian

Kimmeridgian

Oxfordian

Middle

Callovian

Bathonian

Bajocian

Aalenian

Lower

Toarcian

Pliensbachian

Sinemurian

Hettangian

Triassic

Upper

Rhaetian

Norian

Carnian

Middle

Ladinian

Anisian

Lower

Scythian

Popular pages

Liopleurodon

Plesiosaurus

Locomotion

Living plesiosaurs?

Crystal Palace plesiosaurs

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Further reading

Playtime

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The skeletons in the site header are (from left to right): Kronosaurus (in the Museum of Comparative Zoology, Harvard University, Cambridge), Thalassomedon (in the American Museum of Natural History, New York), Cryptoclidus (In the Hunterian Museum and Art Gallery, Glasgow), Rhomaleosaurus (in the Natural History Museum, London), Dolichorhynchops (in the Smithsonian Institution's National Museum of Natural History, Washington) and Thalassiodracon (in the Natural History Museum, London).

©2011 Copyright Adam S. Smith. This site opened in June 2001. Last updated April 2013.