Genus

Valid Extinct

Claosaurus

Marsh 1890

Claosaurus is a genus of hadrosauroid dinosaur that lived during the Late Cretaceous Period (Santonian-Campanian) of what is now North America. The type and only known valid species is Claosaurus agilis. Traditionally classified as an early member of the family Hadrosauridae, a 2008 analysis found Claosaurus to be outside of the clade containing Hadrosaurus and other hadrosaurids, making it the closest non-hadrosaurid relative of true hadrosaurids within the clade Hadrosauromorpha.

Temporal range

Triassic

Jurassic

Cretaceous

Paleogene

Neogene

252 201 145 66 0 Ma

PBDB occurrences

Group

Dinosaures

Herbivore Ground dwelling, gregarious Terrestrial

click to enlarge

Partial skeleton of Claosaurus agilis (holotype YPM 1190). (A) Right ilium in lateral view. (B) Partial postorbital in lateral view. (C) Distal process of the right ischium in lateral view. (D) Mounted partial skeleton of YPM 1190. (E) Coronoid process of the right dentary in lateral view. (F) Fragment of maxilla in lateral view. (G) Detail of the maxillary tooth crowns in (F). (H) Fragment of maxilla in lateral view. (I) Detail of a maxillary tooth crown in (H). © Albert Prieto-Márquez1, Gregory M. Erickson2, Jun A. Ebersole3 · CC BY 4.0 · Wikimedia

PBDB ↗ Wikipedia ↗

Classification

Dinosauria Unranked clade

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Ornithischia Unranked clade

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Neornithischia Unranked clade

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Pyrodontia Unranked clade

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Cerapoda Unranked clade

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Ornithopoda Suborder

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Iguanodontia Infraorder

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Euiguanodontia Unranked clade

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Dryomorpha Unranked clade

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Ankylopollexia Unranked clade

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Styracosterna Unranked clade

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Hadrosauriformes Unranked clade

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Hadrosauroidea Unranked clade

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Claosaurus Genus

Fossil sites 3 geolocated sites

Distribution

Top countries

🇺🇸 United States

Geological formations

Pierre Shale

Niobrara

Temporal distribution

Campanian (83.6–72.2 Ma)

Coniacian (89.8–85.7 Ma)

Species (2)

Claosaurus affinis nomen dubium, species not entered Claosaurus 84 Ma

Claosaurus agilis 90 Ma

Synonyms (1)

Claosaurus affinis nomen dubium, species not entered Claosaurus

Images 1

Bibliography

Original description

O. C. Marsh. 1890. Additional characters of the Ceratopsidae, with notice of new Cretaceous dinosaurs. American Journal of Science 39:418-426 DOI ↗

Bibliography (3)

G. R. Wieland. 1903. Note on the marine turtle Archelon. I. On the structure of the carapace, II. associated fossils. The American Journal of Science, series 4 15(87):211-216 DOI ↗

E. Douglass. 1902. Dinosaurs in the Fort Pierre Shales and underlying beds in Montana. Science 15(366):31-32 DOI ↗

O. C. Marsh. 1872. Preliminary description of Hesperornis regalis, with notices of four other new species of Cretaceous birds. The American Journal of Science and Arts, series 3 3(13-18):360-365 DOI ↗