Open Paleo

Cionodon

Cope, 1874 sy-ON-oh-don Nomen dubium

From Greek kion meaning 'column/pillar' and Greek odon meaning 'tooth'. Full meaning: 'column tooth', referring to the pillar-like shape of its teeth.

72.2–66.0 million years ago Maastrichtian, Late Cretaceous
Late Cretaceous stages

Cionodon is a dubious genus of hadrosaurid dinosaur from the Late Cretaceous. The type species, C. arctatus, was found in the Denver Formation of Lodge Pole Creek, Colorado and was formally described by Edward Drinker Cope in 1874 based on the holotype AMNH 3951, collected in 1873. It is a nomen dubium because it is based on very fragmentary remains. A second species, Cionodon kysylkumensis (Riabinin, 1931), based on the holotype CCMGE 1/3760 (a set of vertebrae) from Uzbekistan, is known only from fragmentary remains and has since been reclassified as Bactrosaurus kysylkumensis.

Species

Cionodon arctatus Cope, 1874 Nomen dubium

Type species

From Latin 'arctatus' meaning 'compressed', likely referring to the compressed form of the teeth.

Holotype
AMNH 3951 , American Museum of Natural History
Material
Portion of the right maxilla, two dorsal vertebrae, the distal end of metatarsal III, and the proximal and distal ends of an ulna
Horizon
Maastrichtian, Late Cretaceous , 72.2–66.0 million years ago
Locality
Colorado, United States Cope names no locality and no horizon beyond "the Laramie", and says only that the material came from two Colorado localities not many miles apart. Carpenter and Young (2002) file it under the Laramie Formation but state that it may equally have come from the Denver Formation exposed along another drainage. The "Lodge Pole Creek" locality repeated in later compilations is an error introduced by Lull and Wright (1942), who took it from the opening section of Cope's paper, which describes Pliocene beds, and attached it to Cope's Cretaceous footnote.

References

  1. Carpenter, K.; Young, D. B. (2002). Late Cretaceous dinosaurs from the Denver Basin, Colorado. Rocky Mountain Geology 37(2): 237-254.

    Reviews the Denver Basin fauna, files the holotype under the Laramie Formation while leaving the Denver Formation open, and rejects the Lodge Pole Creek locality on stratigraphic grounds.

    carpenter2002a
  2. Cope, E. D. (1874). Report on the stratigraphy and Pliocene vertebrate paleontology of northern Colorado. Bulletin of the United States Geological and Geographical Survey of the Territories 1(1): 9-22.

    Names the species in a footnote, on a collection made by an assistant from strata in Colorado the author correlates with the Great Lignite, without a locality.

    cope1874a
  3. Cope, E. D. (1875). Report on the Vertebrate Paleontology of Colorado. United States Geological Survey of the Territories 429-533.

    Fuller redescription; corrects the original spelling "Cinodon" (a proofreader's error) to Cionodon. Places the material at one of two localities in Colorado "not many miles apart", neither named.

    cope1875a
  4. Riabinin, A. N. (1931). Ostatki dinozavrov iz verkhnego mela nizov'ev r. Amu-Dar'i [On the dinosaurian remains from the Upper Cretaceous of the lower parts of the Amu-Daria River]. Zapiski Rossiyskogo Mineralogicheskogo Obshchestva (ser. 2) 60(1): 114-118.

    Named Cionodon kysylkumensis on Uzbek vertebrae.

    riabinin1931b
  5. Lull, R. S.; Wright, N. E. (1942). Hadrosaurian Dinosaurs of North America. Geological Society of America Special Papers 40: 1-272. Geological Society of America. doi:10.1130/spe40-p1 lull1942a
  6. Brett-Surman, M. K. (1989). A revision of the Hadrosauridae (Reptilia: Ornithischia) and their evolution during the Campanian and Maastrichtian. 1-272. Doctoral thesis, The George Washington University.

    Finds that none of the type elements permits a diagnosis at any level, and calls Cionodon a nomen dubium.

    brett-surman1989a