''Crosbysaurus'' 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 ...

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

archosauromorph that lived in the

Late Triassic The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch a ...

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

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, and

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

. It is known from the Chinle Formation and Dockum Group rock units from the southwestern United States. 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 ...

is ''C. harrisae'', and the only known material includes teeth. 11 specimens are known, each including a single tooth. ''Crosbysaurus'' was originally identified as an ornithischian dinosaur by Andrew Heckert when it was first described in 2004. Further work has shown that it is likely an archosauromorph based on the features of its teeth, and it may belong to

Archosauriformes Archosauriformes (Ancient Greek, Greek for 'ruling lizards', and Latin for 'form') is a clade of diapsid reptiles encompassing Archosaur, archosaurs and some of their close relatives. It was defined by Jacques Gauthier (1994) as the clade stemmin ...

. The taxon is likely valid as it differs from other genera from the same region known from teeth like '' Revueltosaurus'', '' Tecovasaurus'', '' Krzyzanowskisaurus'', '' Lucianosaurus'', and '' Protecovasaurus''.

Description

The teeth of ''Crosbysaurus'' are triangular in outline with serrations on both edges. Almost all specimens have "compound denticles"; serrations with their own subdivisions. The serrations on the trailing (posterior/distal) edge of the tooth are always larger than the leading (anterior/mesial) edge. The teeth are small, approximately 3-5 millimeters tall. Owing to their blunt outline it is presumed that ''Crosbysaurus'' was a herbivore.

References

* https://translate.google.com/translate?hl=en&sl=de&u=http://simonkrauter.ntux.at/newdinorama/dinos/c/crosbysaurus/daten.htm&prev=/search%3Fq%3DCrosbysaurus%2B%26hl%3Den%26lr%3D%26sa%3DG Archosauriformes Prehistoric reptile genera Late Triassic reptiles of North America Fossil taxa described in 2004 {{triassic-reptile-stub