Open Paleo

Ornithomimus

Marsh, 1890 or-NITH-o-MIEM-us /ˌɔːrnɪθəˈmaɪməs, -θoʊ-/

From Greek ornitho- (ὄρνις/ὀρνίθ-, 'bird') and mimos (μῖμος, 'mimic' or 'imitator'), meaning 'bird mimic'

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

Ornithomimus is a genus of ornithomimid theropod dinosaurs from the Campanian and Maastrichtian ages of the Late Cretaceous in western North America. Ornithomimus was a swift, bipedal dinosaur which was covered in feathers and equipped with a small toothless beak that may indicate an omnivorous diet. It is usually classified into two species: the type species, Ornithomimus velox, and a referred species, Ornithomimus edmontonicus.

Diagnosis

  1. Astragalus with very large ascending process, larger than in any dinosaur hitherto known
  2. Tibia and larger limb bones hollow with thin walls
  3. Three functional metatarsals: second and fourth increased in size at proximal ends and meeting in front; third metatarsal diminished and displaced posteriorly as in birds
  4. Metatarsal arrangement corresponds to bird anatomy rather than typical dinosaur pattern

Species (2)

Ornithomimus velox Marsh, 1890

Type species

From Latin 'velox' meaning 'swift'.

Syntypes
YPM 542, YPM 548 , Yale Peabody Museum of Natural History
Material
Left tibia, left metatarsals, phalanges of second digit, left metacarpals
Horizon
Denver Formation, Maastrichtian, Late Cretaceous , 72.2–66.0 million years ago
Locality
south side of West Morrison Road, about 370 m east of the intersection of Kipling Street, Colorado, United States

Ornithomimus edmontonicus Sternberg, 1933

Named for the Edmonton Formation of Alberta, from which the holotype was recovered.

Holotype
NMC 8632 , Canadian Museum of Nature
Material
Fragments of three vertebrae, dorsal and abdominal ribs, proximal ends of both scapulae, coracoids, and humeri, right forelimb, distal end of left femur, both tibiae-fibulae, and right and part of left pes.
Horizon
Horseshoe Canyon Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
west side of Red Deer River, 9 miles southwest of Morrin, Alberta, Canada

Notable specimens

  • TMP 2009.110.0001, TMP 2008.070.0001, TMP 1995.110.0001

    Royal Tyrrell Museum of Paleontology exceptional preservation

    Three feathered skeletons across growth stages: a roughly one-year-old juvenile (TMP 2009.110.0001) and an adult (TMP 2008.070.0001) with body filaments, plus an adult (TMP 1995.110.0001) with pennaceous wing-like forelimb feathers. Only adults bore the wings, suggesting they evolved for display.

    Zelenitsky et al. (2012)

  • UALVP 52531

    University of Alberta Laboratory for Vertebrate Paleontology exceptional preservation

    A densely feathered specimen from the lower Dinosaur Park Formation, the first Ornithomimus to preserve tail feathers, which resembled an ostrich's in structure and distribution. Skin impressions show bare skin from mid-thigh to the feet and a flap of skin connecting the upper thigh to the torso.

    van der Reest et al. (2016)

References

  1. van der Reest, A. J.; Wolfe, A. P.; Currie, P. J. (2016). A densely feathered ornithomimid (Dinosauria: Theropoda) from the Upper Cretaceous Dinosaur Park Formation, Alberta, Canada. Cretaceous Research 58: 108-117. Elsevier BV. doi:10.1016/j.cretres.2015.10.004 vanderreest2016a
  2. Zelenitsky, D. K.; Therrien, F.; Erickson, G. M.; DeBuhr, C. L.; Kobayashi, Y.; Eberth, D. A.; Hadfield, F. (2012). Feathered non-avian dinosaurs from North America provide insight into wing origins. Science 338(6106): 510-514. American Association for the Advancement of Science (AAAS). doi:10.1126/science.1225376 zelenitsky2012a
  3. Marsh, O. C. (1890). Description of new dinosaurian reptiles. American Journal of Science s3-39(229): 81-86. American Journal of Science (AJS). doi:10.2475/ajs.s3-39.229.81 marsh1890b
  4. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

    Source of the hip height estimate.

    jones2026c
  5. Sternberg, C. M. (1933). A new Ornithomimus with complete abdominal cuirass. The Canadian Field-Naturalist 47(5): 79-83. doi:10.5962/p.74515

    Erects Ornithomimus edmontonicus on the abdominal-cuirass skeleton NMC 8632 from the Edmonton Formation of Alberta.

    sternberg1933a
  6. Russell, D. A. (1972). Ostrich Dinosaurs from the Late Cretaceous of Western Canada. Canadian Journal of Earth Sciences 9(4): 375-402. Canadian Science Publishing. doi:10.1139/e72-031

    Redescription of ornithomimids recognizing O. edmontonicus as the valid second species and revising the family's systematics.

    russell1972a
  7. Claessens, L. P. A. M.; Loewen, M. A. (2016). A redescription of Ornithomimus velox Marsh, 1890 (Dinosauria, Theropoda). Journal of Vertebrate Paleontology 36(1): e1034593. Informa UK Limited. doi:10.1080/02724634.2015.1034593 claessens2016a