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. A clade is a term belonging to the discipline of cladistics. ... black: range of Crocodilia Families Gavialidae Alligatoridae Crocodylidae Crocodilia is an order of large reptiles that appeared about 84 million years ago in the Late Cretaceous Period (Campanian stage). ... The Jurassic Period is a major unit of the geologic timescale that extends from about 199. ... // The Cretaceous Period (pronounced ) is one of the major divisions of the geologic timescale, reaching from the end of the Jurassic Period (i. ...

Metriorhynchids were the only group of archosaurs to become fully adapted to the marine realm, becoming pelagic in lifestyle. Clades Crurotarsi Aetosauria Crocodilia (crocodiles) Phytosauria Rauisuchia Ornithodira Aves (birds) Dinosauria Pterosauria Archosaurs (Greek for ruling lizards) are a group of diapsid reptiles that is represented today by birds and crocodiles and which also included the dinosaurs. ... The pelagic zone is the part of the open sea or ocean comprising the water column, i. ...

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. For other uses, see England (disambiguation). ...

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. Type specimens When a new species is discovered, more important than creating a new and unique name for the species is developing a reasonably detailed description. ... Paleo Template Project Metriorhynchus was an prehistoric marine crocodile that lived in the Jurassic Period. ... Species (type) Teleidosaurus was the most plesiomorphic genus of marine crocodyliform within Metriorhynchidae, and is known from the Bajocian and Bathonian of the Middle Jurassic. ... Species (type) Geosaurus was a small, gracile genus of marine crocodyliform within Metriorhynchidae. ... Species (type) Dakosaurus was a genus within Metriorhynchidae that was large in size, with lateromedially compressed and serrated teeth. ... Enaliosuchus was a genus of marine crocodiliform within Metriorhynchidae that lived during the Valanginian epoch of the Early Cretaceous. ... In scientific classification, a nomen dubium (Latin for doubtful name, plural nomina dubia) is a scientific name that is valid but of unknown or doubtful application: that is, it may be impossible to determine whether a specimen belongs to that group or not. ... Aggiosaurus is a prehistoric reptile of the late Jurassic. ... Neustosaurus is a genus of marine crocodyliform from the Early Cretaceous. ...

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.