Genus
Valid Extinct

Styxosaurus

Welles 1943

Styxosaurus is a genus of elasmosaurid plesiosaur that lived during the Late Cretaceous period. Three species are known: S. snowii, S. browni, and S. rezaci. Fossils are known from North America and are mainly found in the Niobrara and Pierre Shale formations. Older fossils are known from the Graneros Shale.

Temporal range
Triassic
Jurassic
Cretaceous
Paleogene
Neogene
252 201 145 66 0 Ma
PBDB occurrences
8
Group
Sauroptérygiens
Carnivore aquatic, depth=surface Marine
Styxosaurus
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Wikimedia
PBDB ↗ Wikipedia ↗
Classification
Sauropterygia Suborder
›
Plesiosauria Order
›
Plesiosauroidea Superfamily
›
Elasmosauridae Family
›
Euelasmosaurida Unranked clade
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Elasmosaurinae Unranked clade
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Styxosaurus Genus
Fossil sites 8 geolocated sites
Distribution
Top countries
🇺🇸 United States
8
Geological formations
Pierre Shale
5
Niobrara
3
Temporal distribution
Campanian (83.6–72.2 Ma)
5
Santonian (85.7–83.6 Ma)
2
Coniacian (89.8–85.7 Ma)
1
Species (5)
Alzadasaurus pembertoni subjective synonym of Styxosaurus snowii 86 Ma
Hydralmosaurus serpentinus
Styxosaurus browni 84 Ma
Styxosaurus snowii 86 Ma
Thalassonomosaurus marshii nomen dubium, species not entered Styxosaurus 90 Ma
Synonyms (2)
Hydralmosaurus subjective synonym of Styxosaurus
Thalassonomosaurus marshii nomen dubium, species not entered Styxosaurus
Images 1
Bibliography
Original description
S. P. Welles. 1943. Elasmosaurid plesiosaurs with description of new material from California and Colorado. Memoirs of the University of California 13:125-254
Bibliography (7)
R. A. Otero. 2016. Taxonomic reassessment of Hydralmosaurus as Styxosaurus: new insights on the elasmosaurid neck evolution throughout the Cretaceous. PeerJ 4:e1777:1-60 DOI ↗
D. J. Cicimurri and M. J. Everhart. 2001. An elasmosaur with stomach contents and gastroliths from the Pierre Shale (Late Cretaceous) of Kansas. Transactions of the Kansas Academy of Science 104(3-4):129-143 DOI ↗
K. Carpenter. 1999. Revision of North American elasmosaurs from the Cretaceous of the Western Interior. Paludicola 2(2):148-173
J. E. Martin and L. E. Kennedy. 1988. A plesiosaur with stomach contents from the Late Cretaceous (Campanian) Pierre Shale of South Dakota: a prelimiinary report. Proceedings of the South Dakota Academy of Sciences 67:76-79
S. P. Welles and J. D. Bump. 1949. Alzadasaurus pembertoni, a new elasmosaur from the Upper Cretaceous of South Dakota. Journal of Paleontology 23(5):521-535
S. W. Williston. 1906. North American plesiosaurs: Elasmosaurus, Cimoliasaurus, and Polycotylus. The American Journal of Science, series 4 21:221-236 DOI ↗
S. W. Williston. 1890. A new plesiosaur from the Niobrara Cretaceous of Kansas. Transactions of the Kansas Academy of Science 12:174-178 DOI ↗