Picrocleidus
Extinct genus of reptiles
From Wikipedia, the free encyclopedia
Picrocleidus is an extinct genus of plesiosaur from the Middle Jurassic Oxford Clay Formation (Callovian stage) of the United Kingdom.
| Picrocleidus Temporal range: Middle Jurassic, | |
|---|---|
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| Fossils from both specimens of P. beloclis | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Superorder: | †Sauropterygia |
| Order: | †Plesiosauria |
| Superfamily: | †Plesiosauroidea |
| Family: | †Cryptoclididae |
| Genus: | †Picrocleidus Andrews, 1910 |
| Type species | |
| †Muraenosaurus beloclis Seeley, 1892 | |
Discovery and naming
The holotype was discovered in the Oxford Clay Formation in Peterborough, England and acquired by Alfred Nicholson Leeds.[1][2] It was initially assigned to Muraenosaurus as M. beloclis by Seeley in 1892.[3] The specific name means "arrow clavicle", referring to the triangular interclavicula. M. beloclis was moved to its own genus Picrocleidus by Charles William Andrews in 1910.[2][4] The generic name is derived from Greek pikros, "sharp", en kleis, "key", again referring to the clavicles.
Five specimens are known:
The holotype specimen BMNH R1965, a postcranial skeleton.
Specimen BMNH R3698, a skeleton with skull, including a complete tail.
Specimen BMNH R2429, an old individual consisting of anterior and posterior cervical vertebrae, pectorals and the first dorsal, some dorsal ribs, the shoulder-girdle, and the left humerus.[2]
Specimen BMNH R2739, consisting of a basisphenoid and parasphenoid, cervical vertebrae, sacrals with the sacral ribs, an anterior caudal, some ventral ribs, both radii, odd paddle-bones, portions of ilia, ischia, and pubes.[1]
Specimen HM 2981666: a young individual.
Classification
Picrocleidus has previously been considered synonymous with Muraenosaurus although there are doubts in the relationship between the two groupings.[5]
Picrocleidus is currently classified as a member of the Cryptoclididae.[4]
