Metriorhynchidae
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Extinct (fossil)
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Metriorhynchids were a group of aquatic crocodilians that lived in seas of the Jurassic and Cretaceous periods. Their fore-legs were reduced and paddle-like, and unlike their living cousins they lost their osteoderms ("armour scutes"). Their body shape maximised hydrodynamy, as did having a tail that had a fish-like fin.
Metriorhynchids were the only group of archosaurs to become adapted to the marine realm.
[edit] Geographical Distribution
The family has a wide geographic distribution, with material found in England, France, Switzerland, Germany, Russia, Cuba, Mexico, Argentina and Chile.
[edit] Genera
The type genus for Metiorhynchidae is Metriorhynchus from the Middle to Late Jurassic. Other genera included within this family are Teleidosaurus, Geosaurus, Dakosaurus and Enaliosuchus. Genera considered nomina dubia within this family are Aggiosaurus and Neustosaurus.
The genera Purranisaurus and Suchodus are currently considered junior synonyms of Metriorhynchus, while the genus Cricosaurus has been variously considered a junior synoynm of Metriorhynchus, Geosaurus or Dakosaurus by different palaeontologists.
