Paleontology Wiki
Conservation status
Extinct (fossil)
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Superorder: Dinosauria
Order: Ornithischia
Suborder: Ornithopoda
Family: Hypsilophodontidae
Dollo, 1882

See text.

Hypsilophodonts were small ornithopod dinosaurs. The group traditionally has included almost all ornithopods other than iguanodonts, but recent phylogenetic analyses have found that the group is mostly paraphyletic and the taxa within usually represent a stepwise arrangement leading up to Iguanodontia (Weishampel et al., 2003; Norman et al, 2004). Thus, the only certain member at this time is Hypsilophodon.


(after Norman et al., 2004, the most recent review, with updates from Butler, 2005, and Barrett et al., 2005)

Both subfamilies are informal names that have been applied by others to specific subgroups.

    • Othnielosaurus
    • Orodromeus
    • Subfamily Hypsilophodontinae
      • Hypsilophodon
      • Zephyrosaurus
    • Gasparinisaura
    • Subfamily Thescelosaurinae
      • Bugenasaura
      • Parksosaurus
      • Thescelosaurus

The following genera were regarded as valid, but weren't classified (Norman et al, 2004):

  • Atlascopcosaurus
  • Drinker
  • "Gongbusaurus" wucaiwanensis (= "Eugongbusaurus")
  • Fulgurotherium
  • Leaellynasaura
  • Notohypsilophodon
  • Qantassaurus
  • Yandusaurus
  • "Proctor Lake hypsilophodont"

Several other genera belong here somewhere, but are very poorly known or outright dubious:

  • Laosaurus
  • Nanosaurus
  • Othnielia (without "Laosaurus" consors)
  • Phyllodon


Hypsilophodonts were small (often 1-2 m [3.28 to 6.56 ft] long), bipedal, cursorial herbivores (Norman et al., 2004). The typical informal comparison has been to gazelles.


  • Barrett, P.M., Butler, R.J., and Knoll, F. 2005. Small-bodied ornithischian dinosaurs from the Middle Jurassic of Sichuan, China. Journal of Vertebrate Paleontology 25(4):823-834.
  • Butler, R.J. 2005. The 'fabrosaurid' ornithischian dinosaurs of the Upper Elliot Formation (Lower Jurassic) of South Africa and Lesotho. Zoological Journal of the Linnean Society 145(2):175-218.
  • Norman, D.B., Sues, H.D., Witmer, L.M., and Coria, R.A. 2004. Basal Ornithopoda. In: Weishampel, D.B., Osmólska, H., and Dodson, P. (eds.). The Dinosauria (second edition). University of California Press:Berkeley 393-412.
  • Weishampel, D.B., Jianu, C.-M., Csiki, Z., and Norman, D.B. 2003. Osteology and phylogeny of Zalmoxes (n. g.), an unusual euornithopod dinosaur from the latest Cretaceous of Romania. Journal of Systematic Palaeontology 1(2):65-123.