{{Short description|Extinct genus of reptiles}} {{Speciesbox | fossil_range = {{Fossil range|140|136}}Valanginian | image = Neustosaurus gigondarum.JPG | image_caption = ''Neustosaurus gigondarum'' | genus = Neustosaurus | parent_authority = Raspail, 1842 | species = gigondarum | authority = Raspail, 1842<ref name="Raspail, 1842">Raspail E. (1842). [https://archive.org/details/bub_gb_6fcTAAAAQAAJ/page/n5/mode/2up Observations sur un nouveau genre de saurien fossile, le ''Neustosaurus gigondarum'']. Paris: 56 pp.</ref> }}
'''''Neustosaurus''''' is a dubious genus of marine crocodyliform from the Early Cretaceous. ''Neustosaurus'' was a carnivore that spent much, if not all, its life out at sea. No ''Neustosaurus'' eggs or nest have been discovered, so little is known of the reptile's lifecycle, unlike other large marine reptiles of the Mesozoic, such as plesiosaurs or ichthyosaurs which are known to have given birth to live young out at sea. Where ''Neustosaurus'' mated, whether on land or at sea, is currently unknown. The name ''Neustosaurus'' means "Swimming lizard", and is derived from the Greek ''Neustos''- ("swimming") and {{lang|grc|σαῦρος}} -''sauros'' ("lizard").
==History of discovery== There is only a single described species within ''Neustosaurus'', the type species ''N. gigondarum''.<ref name="Raspail, 1842"/> The holotype material consists of only the posterior of trunk and the tail, discovered in France, in Gigondas.<ref name="Raspail, 1842"/> However, identifying metriorhynchid genera from post-cranials is not easy,<ref name="Fraas, 1902">Fraas E. 1902. Die Meer-Krocodilier (Thalattosuchia) des oberen Jura unter specieller Berücksichtigung von ''Dacosaurus'' und ''Geosaurus''. ''Paleontographica'' '''49''': 1-72.</ref> as such until diagnostic material is discovered ''Neustosaurus'' is considered nomen dubium.<ref name="Buffetaut, 1982">Buffetaut, E. 1982. Radiation évolutive, paléoécologie et biogéographie des Crocodiliens mésosuchienes. ''Mémoires Societé Geologique de France'' '''142''': 1–88.</ref> ''Neustosaurus'' has been considered a junior synonym of either ''Dakosaurus'' <ref name="Buffetaut, 1982"/> and ''Geosaurus'' <ref name="Piveteau, 1928">Piveteau J. 1928. Le reptile de Gigondas et l’évolution des Métriorhynchidés. ''Annales de Paléontologie'' '''17''': 30-47.</ref> over the past 100 years. In 2009, Young and Andrade published a re-description of ''Geosaurus'', examining its relationships and the validity of species lumped into the genus. They concluded that ''Neustosaurus'' is a nomen dubium, but if new material was discovered it would be the senior synonym of ''Cricosaurus''.<ref name="Young&Andrade2009">Young, Mark T., and Marco Brandalise de Andrade, 2009. "What is ''Geosaurus''? Redescription of ''Geosaurus giganteus'' (Thalattosuchia: Metriorhynchidae) from the Upper Jurassic of Bayern, Germany." ''Zoological Journal of the Linnean Society'', '''157''': 551-585.</ref>
==References== {{Reflist}}
{{Thalattosuchia}} {{Taxonbar|from=Q5229790}}
Category:Early Cretaceous crocodylomorphs Category:Prehistoric pseudosuchian genera Category:Prehistoric marine crocodylomorphs Category:Prehistoric life of Europe