7-578: Pistosauroidea is a group of marine reptiles within the superorder Sauropterygia that first appeared in the latter part of the Early Triassic and were the ancestors of plesiosaurs . Pistosauroids are rare in Triassic marine assemblages, and are represented by only a few fossils from central Europe , the United States , and China . Recent phylogenetic analyses consider the Triassic pistosauroids to be
14-592: A marine environment . Only about 100 of the 12,000 extant reptile species and subspecies are classed as marine reptiles, including marine iguanas , sea snakes , sea turtles and saltwater crocodiles . The earliest marine reptile was Mesosaurus (not to be confused with Mosasaurus ), which arose in the Permian period of the Paleozoic era. During the Mesozoic era, many groups of reptiles became adapted to life in
21-624: A paraphyletic grouping, meaning that they do not form a true clade . Plesiosauria is now placed within Pistosauroidea, while the traditional pistosauroids are successively more basal , or primitive, sauropterygians. Below is a cladogram of pistosauroid relationships from Cheng et al. (2006): Placodontia [REDACTED] Pachypleurosauria [REDACTED] Nothosauria [REDACTED] Corosaurus Cymatosaurus Pistosaurus [REDACTED] Yunguisaurus Augustasaurus Plesiosauria [REDACTED] Below
28-849: A marine lifestyle that they were incapable of venturing onto land and gave birth in the water. Others, such as sea turtles and saltwater crocodiles, return to shore to lay their eggs. Some marine reptiles also occasionally rest and bask on land. Most species of marine reptiles are considered endangered to some degree. All but one species of sea turtles are endangered due to destruction of nesting habitats on coastal lands, exploitation, and marine fishing; many species of sea snakes are threatened or endangered due to commercial exploitation (sale of skins) and pollution especially in Asia; marine iguanas are threatened due to their very limited habitation range. Saltwater crocodiles are at low risk for extinction. Sea turtles Too Many Requests If you report this error to
35-559: Is a cladogram of pistosauroid relationships from Ketchum & Benson, 2011: Cymatosaurus " Pistosaurus postcranium" Bobosaurus Pistosaurus [REDACTED] Yunguisaurus Augustasaurus Plesiosauria [REDACTED] [REDACTED] [REDACTED] [REDACTED] This article about a prehistoric reptile is a stub . You can help Misplaced Pages by expanding it . Marine reptile Marine reptiles are reptiles which have become secondarily adapted for an aquatic or semiaquatic life in
42-556: The Cenozoic, most importantly the sea turtles . Other Cenozoic marine reptiles included the bothremydids , palaeophiid snakes, a few choristoderes such as Simoedosaurus and dyrosaurid crocodylomorphs. Various types of marine gavialid crocodilians remained widespread as recently as the Late Miocene. Some marine reptiles, such as ichthyosaurs, plesiosaurs, metriorhynchid thalattosuchians, and mosasaurs became so well adapted to
49-455: The seas, including such familiar clades as the ichthyosaurs , plesiosaurs (these two orders were once thought united in the group "Enaliosauria", a classification now cladistically obsolete), mosasaurs , nothosaurs , placodonts , sea turtles , thalattosaurs and thalattosuchians . Most marine reptile groups became extinct at the end of the Cretaceous period, but some still existed during
#437562