Temporal range: Late Cretaceous, 65.5Ma
|Species:||† P. mortuarius|
Polyonax (meaning "master over many") was a genus of ceratopsid dinosaur from the late Maastrichtian-age Upper Cretaceous Denver Formation of Colorado, USA. Founded upon poor remains, it is today regarded as a dubious name.
During an 1873 trip through the western US, paleontologist and naturalist Edward Drinker Cope collected some fragmentary dinosaurian material which he soon named as a new genus. Catalogued today as AMNH FR 3950, the type material included three dorsal vertebrae, limb bone material, and what are now known to be horn cores, from a subadult individual. Although it was briefly mixed up with hadrosaurs, and even considered to be a possible synonym of Trachodon, it was recognized as a horned dinosaur in time for the first monograph on horned dinosaurs (1907), wherein it was regarded as based on indeterminate material. Today, the name is used as little more than a historical curiosity, as it dates from a time before horned dinosaurs were known to exist. The most recent review listed it as an indeterminate ceratopsid.
- Cope, E.D. (1874). Report on the stratigraphy and Pliocene vertebrate paleontology of northern Colorado. Bulletin of the U.S. Geological and Geographical Survey of the Territories. 9:9-28.
- "American Museum of Natural History - Division of Paleontology - FR 3950".
- Glut, D.F. (1997). "Polyonax". Dinosaurs: The Encyclopedia. McFarland & Company. pp. 723–724. ISBN 0-89950-917-7.
- Hatcher, J.B. (1902). The genus and species of the Trachodontidae (Hadrosauridae, Claosauridae) Marsh. Annals of the Carnegie Museum 14(1):377-386.
- Hatcher, J.B., Marsh, O.C., and Lull, R.S. (1907). The Ceratopsia. Government Printing Office:Washington, D.C., 300 pp. ISBN 0-405-12713-8
- Dodson, P. (1996). The Horned Dinosaurs. Princeton University Press:Princeton, New Jersey. ISBN 0-691-02882-6.
- Dodson, P., Forster, C.A., and Sampson, S.D. (2004). Ceratopsidae. In: Weishampel, D.B., Dodson, P., and Osmólska, H. (eds.). The Dinosauria (second edition). University of California Press:Berkeley, 494-513. ISBN 0-520-24209-2.
- Romer, A.S. (1956). Osteology of the Reptiles. University of Chicago Press:Chicago, 1-772. ISBN 0-89464-985-X.
- Lambert, D., and the Diagram Group. (1990). The Dinosaur Data Book. Facts on File:Oxford, England, 320 p.