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Leptocleidus Temporal range: Early Cretaceous, 135–125 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Life restoration of L. capensis
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Superorder:	†Sauropterygia
Order:	†Plesiosauria
Family:	†Leptocleididae
Genus:	†Leptocleidus Andrews, 1922
Species
†L. capensis (Andrews, 1911 ) Cruikshank, 1997 †L. clemai Cruikshank and Long, 1997 †L. superstes Andrews, 1922 (type)
Synonyms
Peyerus capensis (Andrews, 1911) Stromer, 1935

Leptocleidus is an extinct genus of plesiosaur, belonging to the family Leptocleididae. It was a small plesiosaur, measuring only up to 3 m (9.8 ft).

Discovery

In short, the term Leptocleidus means "slender clavicle". It comes from a merge of the Greek words λεπτοσ, meaning "slender" and κλειδ (also spelled κλεισ) meaning clavicle.

Leptocleidus is known from the following sediments:

• L. capensis is known from the Sundays River Formation (upper Valanginian age), Cape Province, South Africa.
• L. clemai found near Kalbarri in the Carnarvon Basin (Hauterivian-Barremian age) Western Australia.
• L. superstes is known from the Upper Weald Clay (Barremian age), Sussex, England.

A specimen from the Vectis Formation (lower Aptian age), Isle of Wight, found in 1995 and seen as a "Leptocleidus sp.", was named as a separate genus Vectocleidus in 2012.

Description

With large clavicles and interclavicle and small scapulae, Leptocleidus resembled the Early Jurassic Rhomaleosaurus and members of the Cretaceous family, Polycotylidae. The animal had 21 teeth on either side of its maxilla and approximately 35 teeth on each side of the mandible. The Leptocleidus' triangle-shaped skull had a crest running from a ridge on the end of the nose to the nasal region. Differing from pliosaurids, Leptocleidus had single-headed cervical ribs and a deep depression in the centra of the neck vertebrae.

Leptocleidus, unlike many plesiosaurs, lived in shallow lagoons and likely visited brackish and fresh water systems (such as the mouths of large rivers). This led Arthur Richard Ivor Cruickshank to infer that this movement to fresh water was an attempt to flee larger plesiosaurs and pliosaurs. Most species are known from The British Isles but L. capensis was discovered in Cape Province, South Africa.

Classification

Cladogram based on Ketchum and Benson (2011):

See also

• List of plesiosaur genera
• Timeline of plesiosaur research

References

1. Ketchum, H. F.; Benson, R. B. J. (2010). "Global interrelationships of Plesiosauria (Reptilia, Sauropterygia) and the pivotal role of taxon sampling in determining the outcome of phylogenetic analyses". Biological Reviews. 85 (2): 361–392. doi:10.1111/j.1469-185X.2009.00107.x. PMID 20002391. S2CID 12193439.
2. Smith AS, Dyke GJ. 2008. The skull of the giant predatory pliosaur Rhomaleosaurus cramptoni: implications for plesiosaur phylogenetics. Naturwissenschaften e-published 2008.
3. ^ Cruikshank A. R. I. (1997). "A lower Cretaceous Pliosauroid from South Africa". Annals of the South African Museum. 105: 206–226.
4. Hilary F. Ketchum; Roger B. J. Benson (2011). "A new pliosaurid (Sauropterygia, Plesiosauria) from the Oxford Clay Formation (Middle Jurassic, Callovian) of England: evidence for a gracile, longirostrine grade of Early-Middle Jurassic pliosaurids". Special Papers in Palaeontology. 86: 109–129.

Further reading

• O'Keefe F. R. (2001). "A cladistic analysis and taxonomic revision of the Plesiosauria (Reptilia: Sauropterygia)". Acta Zoologica Fennica. 213: 1–63.

External links

• Leptocleidus on DinoWight
• http://plesiosauria.com/leptocleidus
• https://web.archive.org/web/20070922021505/http://www.palaeos.com/Vertebrates/Units/220Lepidosauromorpha/220.520.html#Leptocleidus
• https://web.archive.org/web/20070922061721/http://www.plesiosaur.com/database/genusIndividual.php?i=73

v t e Sauropterygia
Kingdom: Animalia Phylum: Chordata Class: Sauropsida Subclass: Diapsida Clade: Neodiapsida Sauropsida see Sauropsida Sauropterygia see below↓
Sauropterygia Sauropterygia Alexeyisaurus Atopodentatus Palatodonta? Pomolispondylus? Hanosaurus? Helveticosauridae? Eusaurosphargis? Helveticosaurus Saurosphargidae Hemilopas? Largocephalosaurus Prosaurosphargis Saurosphargis Sinosaurosphargis Stauromatodon? Placodontia Paraplacodus Pararcus Placodus Cyamodontoidea Cyamodus Glyphoderma Henodus Macroplacus Parahenodus Placochelys Protenodontosaurus Psephochelys Psephoderma Psephosauriscus Psephosaurus Sinocyamodus Eosauropterygia see below↓
Eosauropterygia Eosauropterygia Corosaurus Cymatosaurus Pachypleurosauria Anarosaurus Chusaurus Dactylosaurus Dawazisaurus? Diandongosaurus Dianmeisaurus Dianopachysaurus Hanosaurus? Honghesaurus Keichousaurus Luopingosaurus Majiashanosaurus Neusticosaurus Odoiporosaurus Prosantosaurus Panzhousaurus Qianxisaurus Serpianosaurus Wumengosaurus Nothosauroidea Brevicaudosaurus Hispaniasaurus? Sanchiaosaurus Simosauridae Paludidraco Simosaurus Nothosauridae Ceresiosaurus Germanosaurus Lariosaurus Metanothosaurus Nothosaurus Proneusticosaurus Silvestrosaurus Pistosauroidea Augustasaurus Bobosaurus Chinchenia Kwangsisaurus Pistosaurus Tanaisosaurus Wangosaurus Yunguisaurus Plesiosauria see below↓
Plesiosauria Plesiosauria Anningasaura Bathyspondylus Bobosaurus? Lindwurmia Sinopliosaurus Termatosaurus? Rhomaleosauridae Anningasaura? Archaeonectrus Atychodracon Avalonnectes Bishanopliosaurus? Borealonectes Eurycleidus Lindwurmia? Macroplata Maresaurus Meyerasaurus Rhomaleosaurus Sthenarosaurus Stratesaurus Thaumatodracon Yuzhoupliosaurus? Pliosauridae Anguanax Arminisaurus Attenborosaurus Cryonectes Hauffiosaurus Marmornectes Pachycostasaurus Rhaeticosaurus Thalassiodracon Thalassophonea Eardasaurus Gallardosaurus Liopleurodon Lorrainosaurus Megalneusaurus UANL-FCT-R2? Peloneustes "Pliosaurus" andrewsi Pliosaurus Simolestes Brachaucheninae Acostasaurus Brachauchenius Eiectus Kronosaurus Luskhan Makhaira Megacephalosaurus Monquirasaurus Polyptychodon Sachicasaurus Stenorhynchosaurus Plesiosauroidea Eoplesiosaurus Eretmosaurus Franconiasaurus Leurospondylus Plesiopharos Plesiopterys Plesiosaurus Westphaliasaurus Microcleididae Hydrorion Lusonectes Microcleidus Occitanosaurus Seeleyosaurus Cryptoclidia see below↓
Cryptoclidia Cryptoclididae Opallionectes Colymbosaurinae Abyssosaurus Colymbosaurus Djupedalia Pantosaurus Spitrasaurus Cryptoclidinae Cryptoclidus Kimmerosaurus Ophthalmothule Tatenectes Muraenosaurinae Muraenosaurus Picrocleidus Tricleidus? Vinialesaurus Xenopsaria Leptocleidia Hastanectes? Nichollssaura? Leptocleididae Brancasaurus Hastanectes? Leptocleidus Nichollssaura? Umoonasaurus? Vectocleidus Polycotylidae Edgarosaurus Manemergus Mauriciosaurus Thililua Palmulasaurinae Pahasapasaurus? Palmulasaurus Occultonectia Plesiopleurodon Sulcusuchus Polycotylinae Eopolycotylus Georgiasaurus Polycotylus Scalamagnus Serpentisuchops Trinacromerum Dolichorhynchia Dolichorhynchops Martinectes Unktaheela Elasmosauridae Callawayasaurus Cimoliasaurus Eromangasaurus Goniosaurus Jucha Lagenanectes Leivanectes Mauisaurus Ogmodirus Orophosaurus Plesioelasmosaurus Scanisaurus Wapuskanectes Woolungasaurus Euelasmosaurida Cardiocorax Libonectes Thalassomedon Elasmosaurinae Albertonectes Elasmosaurus Fluvionectes Hydrotherosaurus? Nakonanectes Styxosaurus Terminonatator Weddellonectia Aphrosaurus Chubutinectes Futabasaurus Fresnosaurus? Hydrotherosaurus? Kawanectes Marambionectes Morenosaurus Tuarangisaurus Vegasaurus Zarafasaura? Aristonectinae Alexandronectes Aristonectes Kaiwhekea Morturneria Wunyelfia

• Plesiosaurs
• Early Cretaceous plesiosaurs of Europe
• Early Cretaceous plesiosaurs
• Fossil taxa described in 1922
• Early Cretaceous reptiles of Australia
• Plesiosaurs of Oceania
• Plesiosaurs of Africa
• Taxa named by Charles William Andrews
• Sauropterygian genera