Metriorhynchidae

thumb|Life restoration of members of the Metriorhynchinae compared to a human Metriorhynchidae is an extinct family of specialized, aquatic metriorhynchoid crocodyliforms from the Middle Jurassic to the Early Cretaceous period (Bajocian to early Aptian) of Europe, North America and South America. The name Metriorhynchidae was coined by the Austrian zoologist Leopold Fitzinger in 1843. The group contains two subfamilies, the Metriorhynchinae and the Geosaurinae. They represent the most marine adapted of all archosaurs.

==Description== Metriorhynchids are fully aquatic crocodyliforms. Their forelimbs were small and paddle-like, and unlike living crocodylians, they lost their osteoderms ("armour scutes"). Their body shape maximised hydrodynamy (swimming efficiency), as they did have a shark-like tail fluke. Like ichthyosaurs and plesiosaurs, metriorhynchids developed smooth, scaleless skin. However, unlike those marine reptiles, they were poikilothermic with little to no endothermic ability.