Leptocleidus

Taxobox
name = "Leptocleidus"
fossil_range = Early Cretaceous

---

image_width = 250px
image_caption = "Leptocleidus capensis"
regnum = Animalia
phylum = Chordata
classis = Sauropsida
superordo = Sauropterygia
unranked = Eusauropterygia
ordo = Plesiosauria
familia = Leptocleididae
genus = "Leptocleidus"
genus_authority = Andrews, 1922
subdivision_ranks = Species
subdivision =
*" L. capensis " Cruikshank, 1997
*" L. clemai " Cruikshank and Long, 1997
*" L. superstes " (type) Andrews, 1922
synonyms =
*"Peyerus"

"Leptocleidus" is an extinct genus of pliosaur, 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 is the only known pliosaur to be found in sediments on the Isle of Wight.

Etymology

In short, the term "Leptocleidus" means "slender clavicle". It comes from a merge of the Greek words "λ ε π τ ο σ", meaning "slender" and "κ λ ε ι δ" (also spelled "κ λ ε ι σ") meaning clavicle.

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 other pliosaurids, "Leptocleidus" had single-headed cervical ribs and a deep depression in the centra of the neck vertebrae. "Leptocleidus" was on an average of 3 meters (10 feet) long. "Leptocleidus superstes" however, was found to be almost 50% smaller (1.5m, 5ft) making it the smallest known species.

Distribution and habitat

"Leptocleidus", unlike many pleisiosaurs, lived in shallow lagoons and likely visited brackish and fresh water systems (such as the mouths of large rivers). This led Cruikshank 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.

"Leptocleidus" is known from the following sediments:
*Upper Weald Clay, Sussex, England.
*Sundays River Formation, Cape Province, South Africa Cruikshank, A. R. I. 1997. A lower Cretaceous Pliosauroid from South Africa. "Annals of the South African Museum" 105: 206-226.]
*Vectis formation, Isle of Wight

References

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

*http://www.geocities.com/dinowight/leptocleidus.html
*http://www.plesiosauria.com/leptocleidus.html
*http://www.palaeos.com/Vertebrates/Units/220Lepidosauromorpha/220.520.html#Leptocleidus
*http://www.plesiosaur.com/database/genusIndividual.php?i=73