''Neustosaurus'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of marine

crocodyliform Crocodyliformes is a clade of Crurotarsi, crurotarsan archosaurs, the group often traditionally referred to as "crocodilians". They are the first members of Crocodylomorpha to possess many of the features that define later relatives. They are the ...

from the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

. ''Neustosaurus'' was a

carnivore A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they ar ...

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 The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

, such as

plesiosaur The Plesiosauria or plesiosaurs are an Order (biology), order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appeared in the latest Triassic Period (geology), Period, possibly in the Rhaetian st ...

s or

ichthyosaurs Ichthyosauria is an taxonomy (biology), order of large extinction, extinct marine reptiles sometimes referred to as "ichthyosaurs", although the term is also used for wider clades in which the order resides. Ichthyosaurians thrived during much of ...

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 Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

''Neustos''- ("swimming") and -''sauros'' ("lizard").

History of discovery

There is only a single described species within ''Neustosaurus'', the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

''N. gigondarum''. The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

material consists of only the posterior of trunk and the tail, discovered in

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

, in

Gigondas Gigondas (; ) is a commune in the Vaucluse department in the Provence-Alpes-Côte d'Azur region in Southeastern France. In 2021 it had a population of 430. Geography Gigondas lies in between Vacqueyras and Sablet at the foot of the Dentelles ...

. However, identifying metriorhynchid genera from post-cranials is not easy,Fraas E. 1902. Die Meer-Krocodilier (Thalattosuchia) des oberen Jura unter specieller Berücksichtigung von ''Dacosaurus'' und ''Geosaurus''. ''Paleontographica'' 49: 1-72. as such until diagnostic material is discovered ''Neustosaurus'' is considered

nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium,'' it may be impossible to determine whether a ...

.Buffetaut, E. 1982. Radiation évolutive, paléoécologie et biogéographie des Crocodiliens mésosuchienes. ''Mémoires Societé Geologique de France'' 142: 1–88. ''Neustosaurus'' has been considered a

junior synonym In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The botanical and zoological codes of nomenclature treat the concept of synonymy differently. ...

of either ''

Dakosaurus ''Dakosaurus'' is an extinct genus of crocodylomorph within the family Metriorhynchidae that lived during the Late Jurassic and Early Cretaceous. It was large, with teeth that were serrated and compressed lateromedially (flattened from side to s ...

'' and ''

Geosaurus ''Geosaurus'' is an extinct genus of marine crocodyliform within the family Metriorhynchidae, that lived during the Late Jurassic and the Early Cretaceous. ''Geosaurus'' was a carnivore that spent much, if not all, its life out at sea. No ''Geosa ...

'' Piveteau J. 1928. Le reptile de Gigondas et l’évolution des Métriorhynchidés. ''Annales de Paléontologie'' 17: 30-47. 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 In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The botanical and zoological codes of nomenclature treat the concept of synonymy differently. ...

of ''

Cricosaurus ''Cricosaurus'' is an extinct genus of marine crocodyliforms of the Late Jurassic. belonging to the family Metriorhynchidae. The genus was established by Johann Andreas Wagner in 1858 for three skulls from the Tithonian (Late Jurassic) of Germany ...

''.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.

References

{{Taxonbar, from=Q5229790 Early Cretaceous crocodylomorphs Prehistoric pseudosuchian genera Prehistoric marine crocodylomorphs Prehistoric life of Europe