Simolestes (meaning "hearkening thief") is an extinct pliosaurid genus that lived in the Middle to Late Jurassic. The type specimen, BMNH R. 3319 is an almost complete but crushed skeleton diagnostic to Simolestes vorax, dating back to the Callovian of the Oxford Clay formation, England. The genus is also known from the Callovian and Bajocian of France (S.keileni), and the Tithonian of India (S.indicus). The referral of these two species to Simolestes is dubious, however.
|Diagram of the skull of S. vorax|
S. vorax (type species)
Simolestes possessed a short, high, and wide skull which was built to resist torsional forces when hunting.
The largest specimens of S.vorax reached approximately 4.6 metres (15 ft) in length, if a head to body ratio similar to Liopleurodon is applied. However, large specimens of S.keileni from France suggest some individuals grew more than 6 metres (20 ft) long.
Like most Pliosaurs, Simolestes possessed salt secreting glands, which would have enabled the animal to maintain salt balance and drink seawater. Recent studies on Plesiosaur locomotion indicate that Simolestes, like other Plesiosaurs, possessed a unique bauplan for movement, which differs from modern organisms in similar niches.
It is unclear exactly on Simolestes' feeding habits. The current consensus, however, is that the genus was primarily teuthophagus, consuming belemnites, soft teuthoids and ammonites. It is possible Simolestes was also ecologically separated from other contemporary pliosaur genera such as Liopleurodon and Pachycostasaurus by hunting in deeper waters or at night, as modern cephalopods exhibit diurnal feeding cycles, spending daylight in deeper, safer waters, and rising at night to feed.
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