''Picrocleidus'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

plesiosaur The Plesiosauria or plesiosaurs are an Order (biology), order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appeared in the latest Triassic Period (geology), Period, possibly in the Rhaetian st ...

from the

Middle Jurassic The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relativel ...

Oxford Clay Formation ( Callovian stage) of the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

Discovery and naming

The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

was discovered in the Oxford Clay Formation in

Peterborough Peterborough ( ) is a City status in the United Kingdom, cathedral city in the City of Peterborough district in the Ceremonial counties of England, ceremonial county of Cambridgeshire, England. The city is north of London, on the River Nene. A ...

, England and acquired by Alfred Nicholson Leeds.Andrews, Charles W. (1910). A descriptive catalogue of the marine reptiles of the Oxford Clay, Part 2. British Museum (Nat. Soc.) 13:139-149. It was initially assigned to ''

Muraenosaurus ''Muraenosaurus'' (from the Latin "''Muraena''" meaning "eel" and "''Sauros''" meaning lizard) is an extinct genus of cryptoclidid plesiosaur reptile from the Oxford Clay of Southern England. The genus was given its name due to the eel-like appe ...

'' as ''M. beloclis'' by Seeley in 1892. 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.Muraenosaurus? Reedii, Sp. Nov. and Tricleidus? Laramiensis Knight, American Jurassic Plesiosaurs. ''The Journal of Geology'', ''20'', 4, 344-352. The generic name is derived from Greek ''pikros'', "sharp", en ''kleis'', "key", again referring to the clavicles. Five specimens are known: The

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. 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. Specimen HM 2981666: a young individual.

Classification

''Picrocleidus'' has previously been considered synonymous with ''

'' although there are doubts in the relationship between the two groupings.Wilhelm BC. (2010). A New Partial Skeleton of a Cryptocleidoid Plesiosaur from the Upper Jurassic Sundance Formation of Wyoming. ''Journal of Vertebrate Paleontology '', ''30'', 6, 1736-1742. ''Picrocleidus'' is currently classified as a member of the

Cryptoclididae Cryptoclididae is a family of medium-sized plesiosaurs that existed from the Middle Jurassic to the Early Cretaceous. They had long necks, broad and short skulls and densely packed teeth. They fed on small soft-bodied preys such as small fish and ...

References

{{Taxonbar, from=Q9059430 Middle Jurassic plesiosaurs of Europe Fossil taxa described in 1892 Cryptoclididae Taxa named by Harry Seeley Sauropterygian genera

Discovery and naming

Classification

See also

References