Metriorhynchidae
From Wikipedia, the free encyclopedia
| Metriorhynchidae Fossil range: Middle Jurassic to Early Cretaceous |
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Dakosaurus |
Metriorhynchids were a clade of fully-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 shark-like tail fin.
Metriorhynchids were the only group of archosaurs to become fully adapted to the marine realm, becoming pelagic in lifestyle.
The name Metriorhynchidae was erected by the Austrian zoologist Leopold Fitzinger in 1843.
[edit] Geographical distribution
The family has a wide geographic distribution, with material found in Argentina, Chile, Cuba, England, France, Germany, Italy, Mexico, Poland, Russia and Switzerland.
[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.
The genus Capelliniosuchus, once thought to be a metriorhynchid similar to Dakosaurus. However, Sirotti (1989) demonstrated that it is a junior synonym of Mosasaurus.
[edit] References
- Sirotti A. 1989. Mosasaurus hoffmanni Mantell, 1828 (Reptilia) nelle <<argille scagliose>> di S. Valentino (Reggio E.). Atti della società dei naturalisti e matematici di Modena 120: 135-146.
- Steel R. 1973. Crocodylia. Handbuch der Paläoherpetologie, Teil 16. Stuttgart: Gustav Fischer Verlag,116 pp.
