''Cionodon'' (meaning 'column tooth') is a dubious

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of hadrosauridJ. R. Horner, D. B. Weishampel, and C. A. Forster. 2004. Hadrosauridae. In D. B. Weishampel, H. Osmolska, and P. Dodson (eds.), ''

The Dinosauria ''The Dinosauria'' is an extensive book on dinosaurs, compiled by David B. Weishampel, Peter Dodson, and Halszka Osmólska. It has been published in 2 editions, with the first edition published in 1990, consisting of material from 23 scientists.B ...

'' (2nd edition). ''University of California Press, Berkeley'' 438-463

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...

. The

type species In 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 species that contains the biological type specimen ...

, ''C. arctatus'', was found in the

Denver Formation The Denver Formation is a geological formation that is present within the central part of the Denver Basin that underlies the Denver, Colorado, area. It ranges in age from latest Cretaceous (Maastrichtian) to early Paleocene, and includes sediment ...

of Lodge Pole Creek,

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of t ...

and was formally described by Edward Drinker Cope in 1874 based on the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

AMNH The American Museum of Natural History (abbreviated as AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. In Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 26 i ...

3951, collected in 1873. It is a '' nomen dubium'' because it is based on very fragmentary remains. Two other species have since been described: ''Cionodon kysylkumensis'' ( Riabinin, 1931), based on the holotype CCMGE 1/3760 (a set of

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristi ...

e) from

Uzbekistan Uzbekistan (, ; uz, Ozbekiston, italic=yes / , ; russian: Узбекистан), officially the Republic of Uzbekistan ( uz, Ozbekiston Respublikasi, italic=yes / ; russian: Республика Узбекистан), is a doubly landlocked cou ...

,A. N. Riabinin. 1931. Ostatki dinozavrov iz verkhnego mela nizov'ev r. Amu-Dar'i Amu-Daria_River.html" ;"title="Amu_Darya.html" ;"title="n the dinosaurian remains from the Upper Cretaceous of the lower parts of the Amu Darya">Amu-Daria River">Amu_Darya.html" ;"title="n the dinosaurian remains from the Upper Cretaceous of the lower parts of the Amu Darya">Amu-Daria River ''Zapiski Rossiyskogo Mineralogicheskogo Obshchestva'' 60(1):114-118 and ''Cionodon stenopsis'' (Cope, 1875), discovered in rocks from the Judith River Formation of Alberta, Canada, Alberta, Canada in 1874. E. D. Cope. 1875. On the transition beds of the Saskatchewan district. ''Proceedings of the Academy of Natural Sciences of Philadelphia'' 27:2-3 Although both are probably hadrosaurs, they are known only from fragmentary remains and ''Cionodon kysylkumensis'' has since been reclassified as '' Bactrosaurus kysylkumensis''.

References

Late Cretaceous dinosaurs of North America Hadrosaurs Nomina dubia Fossil taxa described in 1874 Taxa named by Edward Drinker Cope Paleontology in Colorado Maastrichtian genus first appearances Maastrichtian genus extinctions Ornithischian genera {{ornithopod-stub

See also

References