leptocleidus
{{Short description|Extinct genus of reptiles}}
{{Automatic taxobox
| fossil_range = Early Cretaceous, {{fossilrange|135|125}}
| image = Leptocleidus capensis.png
| image_caption = Life restoration of L. capensis
| taxon = Leptocleidus
| authority = Andrews, 1922
| subdivision_ranks = Species
| subdivision =
- {{extinct}}L. capensis (Andrews, 1911 [originally Plesiosaurus capensis]) Cruikshank, 1997
- {{extinct}}L. clemai Cruikshank and Long, 1997
- {{extinct}}L. superstes Andrews, 1922 (type)
| synonyms =
- Peyerus capensis (Andrews, 1911) Stromer, 1935
}}
Leptocleidus is an extinct genus of plesiosaur,{{Cite journal|author1=Ketchum, H. F. |author2=Benson, R. B. J. |year=2010 |title=Global interrelationships of Plesiosauria (Reptilia, Sauropterygia) and the pivotal role of taxon sampling in determining the outcome of phylogenetic analyses |journal=Biological Reviews |volume=85|issue=2 |pages=361–392 |doi=10.1111/j.1469-185X.2009.00107.x |pmid=20002391|s2cid=12193439 }} belonging to the family Leptocleididae.Smith AS, Dyke GJ. 2008. The skull of the giant predatory pliosaur Rhomaleosaurus cramptoni: implications for plesiosaur phylogenetics. Naturwissenschaften e-published 2008. It was a small plesiosaur, measuring only up to {{cvt|3|m|ft}}.
Discovery
{{multiple image
| align = left
| direction = horizontal
| caption_align = center
| total_width = 420
| header = L. capensis (Andrews, 1911)
| image1 =
| alt1 =
| caption1 = Skull in dorsal view
| image2 =
| alt2 =
| caption2 = Skull in palatal view
}}
{{multiple image
| direction = horizontal
| align = left
| caption_align = center
| total_width = 420
| header = L. superstes Andrews, 1922
| image1 = Leptocleidus.jpg
| alt1 =
| caption1 = Cranium (lateral view, top left; ventral (palatal) view, top right) and vertebrae. Length of vertebral series approx. 45 cm
| image2 = Leptocleidus supertes.jpg
| alt2 =
| caption2 = Pectoral girdle in dorsal view (left), anterior view (top right), lateral view (bottom right), right humerus (center), and ribs (left). Length of pectoral girdle approx. 40 cm
}}
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.{{cite journal | author = Cruikshank A. R. I. | year = 1997 | title = A lower Cretaceous Pliosauroid from South Africa | journal = Annals of the South African Museum | volume = 105 | pages = 206–226 }}
- 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
File:Wealden Leptocleidid scale.png (green at the center), compared to a human]]
Cladogram based on Ketchum and Benson (2011):{{cite journal |author1=Hilary F. Ketchum |author2=Roger B. J. Benson |year=2011 |title=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 |journal=Special Papers in Palaeontology |volume=86 |pages=109–129 }}
{{clade| style=font-size:85%;line-height:85%
|label1=Leptocleididae
|1={{clade
|2={{clade
|1=Brancasaurus
|2={{clade
|1=Umoonasaurus
|label2=Leptocleidus
|2={{clade
|1=L. capensis
|2=L. superstes }} }} }} }} }}
See also
{{portal|paleontology}}
References
{{Reflist}}
Further reading
- {{cite journal | author = O'Keefe F. R. | year = 2001 | title = A cladistic analysis and taxonomic revision of the Plesiosauria (Reptilia: Sauropterygia) | journal = Acta Zoologica Fennica | volume = 213 | pages = 1–63 }}
External links
- [http://www.dinowight.org.uk/leptocleidus.html 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
{{Plesiosauria|Leptocleidia}}
{{Taxonbar|from=Q41154953}}
Category:Early Cretaceous plesiosaurs of Europe
Category:Early Cretaceous plesiosaurs
Category:Fossil taxa described in 1922
Category:Early Cretaceous reptiles of Australia
Category:Plesiosaurs of Oceania
Category:Plesiosaurs of Africa