''Sthenarosaurus'' (meaning "strong lizard") is an
extinct genus of
rhomaleosaurid pliosauroid discovered in the
Toarcian
The Toarcian is, in the ICS' geologic timescale, an age and stage in the Early or Lower Jurassic. It spans the time between 182.7 Ma (million years ago) and 174.1 Ma. It follows the Pliensbachian and is followed by the Aalenian.
The Toarc ...
-aged '
Main Alum Shale' (Commune subzone of
Bifrons zone)
[Sepkoski, Jac]
Sepkoski's Online Genus Database – Cephalopoda
/ref> in Whitby, England
England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe ...
.[D. M. S. Watson. 1909. IV. A preliminary note on two new genera of upper Liassic plesiosaurs. ''Memoirs and Proceedings of the Manchester Literary and Philosophical Society'' 54(4):1-28] The type specimen is MMUM LL 8023, a set of postcrania discovered in Whitby. Other indeterminate specimens are known,
Description
The holotype is known from an incomplete skeleton with no skull. A precise reconstruction is not possible, but it is assumed that ''Sthenarosaurus'' was a small plesiosaur, reaching up to long when fully grown. The coracoids were short and thick, while the pelvis was broad and strong. The dorsal vertebrae possessed short, but very broad and high vertebral centers, with thick neural spines. Eighteen cervical vertebrae are preserved, and vary greatly in size: the largest is almost double the smallest; this suggests that if the entire neck had been made up of even a few more vertebrae than those preserved, the animal would have had a strange appearance, due to noticeable thinning of the neck in the head area.[T. E White. 1940. Holotype of '']Plesiosaurus longirostris
''Hauffiosaurus'' is an extinct genus of Early Jurassic (early Toarcian stage) pliosaurid plesiosaur known from Holzmaden of Germany and from Yorkshire of the United Kingdom. It was first named by Frank Robin O’Keefe in 2001 and the type spec ...
'' (Blake) and classification of the plesiosaurs. ''Journal of Paleontology'' 14 (5): 451-467
Classification
''Sthenarosaurus'' has been placed in the Pliosauroidea within Plesiosauria since it was described in 1909.Plesiosaurus
''Plesiosaurus'' (Greek: ' ('), near to + ' ('), lizard) is a genus of extinct, large marine sauropterygian reptile that lived during the Early Jurassic. It is known by nearly complete skeletons from the Lias of England. It is distinguishable by ...
''" '' rostratus''), based on similarities in the shape of the shoulder blades, coracoids and cervical vertebrae.
See also
* List of plesiosaur genera
* Timeline of plesiosaur research
References
Early Jurassic plesiosaurs of Europe
Fossils of Great Britain
Sauropterygian genera
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