Polyonax (meaning "master over many") is a genus of ceratopsid dinosaur from the Late Cretaceous (late Maastrichtian) Denver Formation of Colorado, United States. Founded upon poor remains, it is today regarded as a dubious name.
History 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.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. 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,Hatcher, J.B. (1902). The genus and species of the Trachodontidae (Hadrosauridae, Claosauridae) Marsh. Annals of the Carnegie Museum 14(1):377-386. 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.Hatcher, J.B., Marsh, O.C., and Lull, R.S. (1907). The Ceratopsia. Government Printing Office:Washington, D.C., 300 pp. 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.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. .
It has sometimes been listed as a synonym of Agathaumas,Romer, A.S. (1956). Osteology of the Reptiles. University of Chicago Press:Chicago, 1-772. . or Triceratops.Lambert, D., and the Diagram Group. (1990). The Dinosaur Data Book. Facts on File:Oxford, England, 320 p.
Paleobiology As a ceratopsid, Polyonax would have been a large, quadrupedal herbivore, with brow and nasal horns and a neck frill.
See also
Timeline of ceratopsian research
References