Temporal range: Middle Jurassic, 166 Ma
Holotype femur seen from three angles
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
clade: Dinosauria
Order: Ornithischia
Suborder: Stegosauria
Family: Stegosauridae
Genus: Eoplophysis
Ulansky, 2014
Type species
Eoplophysis vestusus
(von Huene, 1910)

Eoplophysis is a genus of stegosaur known from the Middle Jurassic Cornbrash Formation, Sharp's Hill Formation, and Chipping Norton Formation of England.[1]


It was originally named Omosaurus vetustus by the renowned German paleontologist Friedrich von Huene.[2] The holotype, OUM J.14000, is a two feet long right femur of a juvenile individual from the Middle Jurassic (upper Bathonian) Cornbrash Formation of Oxfordshire, England, although it was probably reworked from the slightly older Forest Marble Formation in view of its eroded nature. Because of the renaming of Omosaurus, an occupied name, as Dacentrurus, O. vetustus was renamed into a Dacentrurus vetustus in 1964.[3]

In the 1980s, researcher Peter Malcolm Galton reviewed all known stegosaur material from the Bathonian of England and concluded that Omosaurus vetustus was valid and should be tentatively referred to Lexovisaurus.[4][5] However, the species was later considered a nomen dubium in both reviews of Stegosauria.[6][7] In their alpha-taxonomic review of stegosaurs, Susannah Maidment and her colleagues noted that OUM J.14000 shares characters present in both sauropods and stegosaurs, but that it lacks synapomorphies exclusive to Stegosauria and assigned it as a Dinosauria indet.[8] Nevertheless, the amateur paleontologist Roman Ulansky coined the new genus Eoplophysis ("Dawn Armed Form") for O. vetustus, noting differences with the femora of other stegosaurs.[9]


  1. http://zoobank.org/NomenclaturalActs/866BDB21-5E62-408E-A999-F8281BD615D5
  2. F. v. Huene. 1910. Über den ältesten Rest von Omosaurus (Dacentrurus) im englischen Dogger [On the oldest remains of Omosaurus (Dacentrurus) from the English Dogger]. Neues Jahrbuch für Mineralogie, Geologie und Paläontologie 1910(1):75-78.
  3. O. Kuhn. 1964. Pars 105. Ornithischia (Supplementum I). In F. Westphal (ed.), Fossilium Catalogus. I: Animalia. IJssel Pers, Deventer, The Netherlands 1-80
  4. Galton, P.M. and Powell, H.P., 1983, "Stegosaurian dinosaurs from the Bathonian (Middle Jurassic) of England, the earliest record of the family Stegosauridae", Geobios, 16: 219–229
  5. Galton P.M. (1985) "British plated dinosaurs (Ornithischia, Stegosauridae), Journal of Vertebrate Paleontology, 5: 211-254
  6. Galton, Peter M.; Upchurch, Paul (2004). "Stegosauria (Table 16.1)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 344-345. ISBN 0-520-24209-2.
  7. P. M. Galton. 1990. Stegosauria. The Dinosauria, D. B. Weishampel, P. Dodson, & H. Osmólska (editors), University of California Press, Berkeley 435-455
  8. S. C. R. Maidment, D. B. Norman, P. M. Barrett and P. Upchurch. 2008. Systematics and phylogeny of Stegosauria (Dinosauria: Ornithischia). Journal of Systematic Palaeontology 6(4):367-407
  9. Ulansky, R. E., 2014. Evolution of the stegosaurs (Dinosauria; Ornithischia). Dinologia, 35 pp. [in Russian]. [DOWNLOAD PDF] http://dinoweb.narod.ru/Ulansky_2014_Stegosaurs_evolution.pdf.

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