Leptocleidus

Genus

Leptocleidus

Author

Andrews, 1922

Classification

Leptocleidus

Age

Valanginian to Barremian (Lower Cretaceous)

Location

Global distribution: England; South Africa, Australia.

Type species

L. superstes

Other species

L. capensis; L. clemai

Referred material

To compile

Lower Cretaceous plesiosaurs are rare, so Leptocleidus is important because it fills a gap in the fossil record of plesiosaurians. Leptocleidus was once considered to be a late surviving member of the family Rhomaleosauridae but it has recently been reidentified as a close relative of polycotylids. The fossils of all known species of Leptocleidus were preserved in inshore brackish or freshwater deposits. This led Cruickshank (1997) to speculate that the large pliosaurids that appeared during the Middle and Late Jurassic may have outcompeted the rhomaleosaurids in the open ocean and forced them to exploit near-shore niches instead.

There are presently three known valid species of Leptocleidus: L. superstes (the type species), L. capensis, and L. clemai. The genus ‘Peyerus’ was proposed for Leptocleidus capensis by Stromer (1935), but that name is now considered a junior synonym of Leptocleidus (Cruickshank (1997).

Pectoral girdle of <i>Leptocleidus superstes</i> in dorsal view (left), anterior view (top right), lateral view (bottom right), right humerus (center), and ribs (left)Length of pectoral girdle approx. 40cm (from Andrews, 1922).
Cranium of <i>Leptocleidus superstes</i> (lateral view, top left; ventral (palatal) view, top right) and vertebrae. Length of vertebral series approx. 45cm (from Andrews, 1922)
Referred <i>Leptocleidus</i> material on display in the Dinosaur Isle Museum, Isle of Wight, UK.
Skull of <i>Leptocleidus capensis</i> in ventral view (from Cruickshank, 1997)
Skull of <i>Leptocleidus capensis</i> in lateral view (from Cruickshank, 1997)
Skull of <i>Leptocleidus capensis</i> in dorsal view (from Cruickshank, 1997)

Leptocleidus superstes

Species

L. superstes

Author

Andrews, 1922

Classification

Sauropterygia
Eosauropterygia
Eusauropterygia
Pistosauroidea
Pistosauria
Plesiosauria
Plesiosauroidea
Leptocleididae
Leptocleidus

Age

Barremian, Lower Cretaceous

Type location

Sussex, England

Type specimen

NHMUK R4828, skull and partial skeleton

Referred material

To compile


Leptocleidus capensis

Species

L. capensis

Author

(Andrews, 1911)

Classification

Sauropterygia
Eosauropterygia
Eusauropterygia
Pistosauroidea
Pistosauria
Plesiosauria
Plesiosauroidea
Leptocleididae
Leptocleidus

Age

Uppermost Valanginian, Early Cretaceous

Type location

Picnic Bush site, overlooking Redhouse Farm, Swartkops River Valley, Cape Province, South Africa

Type specimen

SAM-K5822, a complete skull and partial lower jaw

Referred material

None


Leptocleidus clemai

Species

L. clemai

Author

Cruickshank and Long, 1997

Classification

Sauropterygia
Eosauropterygia
Eusauropterygia
Pistosauroidea
Pistosauria
Plesiosauria
Plesiosauroidea
Leptocleididae
Leptocleidus

Age

Barremian, Early Cretaceous

Type location

Near Kalbarri, Carnarvon Basin, Western Australia

Type specimen

WAM 92.8.1-1 to 68, a partial skeleton

Referred material

WAM 94.1.6-1 to 100, a partial skeleton less well preserved than the holotype