Open Paleo

Gallimimus

Osmólska et al., 1972 GAL-im-EYE-muhs /ˌɡælɪˈmaɪməs/

Chicken mimic; from Latin gallus (chicken) and mimus (mimic), referring to similarities between its neck vertebrae and those of Galliformes

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

Gallimimus is a genus of theropod dinosaur that lived in what is now Mongolia during the Late Cretaceous period. Several fossils in various stages of growth were discovered by Polish-Mongolian expeditions in the Gobi Desert of Mongolia during the 1960s; a large skeleton discovered in this region was made the holotype specimen of the new genus and species Gallimimus bullatus in 1972. The generic name means "chicken mimic", referring to the similarities between its neck vertebrae and those of the Galliformes. The specific name is derived from bulla, a golden capsule worn by Roman youth, in reference to a bulbous structure at the base of the skull of Gallimimus. At the time it was named, the fossils of Gallimimus represented the most complete and best preserved ornithomimid ("ostrich dinosaur") material yet discovered, and the genus remains one of the best known members of the group.

Diagnosis

  1. Very long snout, broad and flattened dorsoventrally at the tip; infratemporal fossa subtriangular with jugal excluded from its borders.
  2. Common exit for third and fourth cranial nerves merges with the optic fissure.
  3. Lower jaw shovel-like anteriorly, with elongated external mandibular fenestra.
  4. Length of presacral vertebral column equal to combined length of femur, tibia-astragalus, and third metatarsal; transition point between caudals 15 and 16.
  5. Humerus longer than scapula; manus equal about a quarter of total forelimb length; ungual of digit III shorter than penultimate phalanx of digit III.
  6. Metatarsus more than 70% of crural length; metatarsal II equal 97% of length of metatarsal IV; pedal digit III equal a third of crural length.

Species

Gallimimus bullatus Osmólska et al., 1972

Type species

From Latin 'bulla', a golden capsule worn by Roman youth around the neck, referring to the bulbous capsule on the parasphenoid at the base of the dinosaur's skull.

Holotype
IGM 100/11 , Paleontological Center, Mongolian Academy of Sciences
Material
Nearly complete skeleton with skull and mandible; braincase well preserved, snout somewhat distorted, lower jaw incomplete; forelimbs almost complete; hind limbs almost complete.
Horizon
Nemegt Formation, Maastrichtian, Late Cretaceous , 72.2–66.0 million years ago
Locality
Tsagaan Khushuu, Ömnögovi, Mongolia Osmolska and colleagues (1972) refer further material from Nemegt, Altan Uul IV and Naran Bulak, none of it from the holotype's locality.

Synonyms of the genus

Name Type Reason
Sanchusaurus nomen nudum Informal name; never met ICZN requirements for formal publication and is treated as referable to Gallimimus. Per Olshevsky's Dinosaur Genera List.

Notable specimens

  • IGM 100/1133

    Paleontological Center, Mongolian Academy of Sciences exceptional preservation

    Skull preserving soft-tissue structures on the beak: the inner side bears columnar structures the describers compared to the lamellae of anseriform bird beaks, central to the debate over whether ornithomimosaurs were filter-feeders or high-fiber herbivores.

    Norell et al. (2001)

  • MPC-D 100F/17

    Paleontological Center, Mongolian Academy of Sciences Found 2009 trace association

    A clenched Gallimimus foot found in 2009 directly associated with a fossil trackway in the Nemegt, a rare instance of tracks preserved together with body fossils; the rest of the skeleton had been removed by fossil poachers.

    Lee et al. (2018)

References

  1. Osmólska, H.; Roniewicz, E.; Barsbold, R. (1972). A new dinosaur, Gallimimus bullatus n. gen., n. sp. (Ornithomimidae) from the Upper Cretaceous of Mongolia. Palaeontologia Polonica 27: 103-143. osmólska1972a
  2. Paul, G. S. (2024). The Princeton Field Guide to Dinosaurs (3rd ed.). Princeton University Press.

    Source of the appearance features.

    paul2024a
  3. Norell, M. A.; Makovicky, P. J.; Currie, P. J. (2001). The beaks of ostrich dinosaurs. Nature 412(6850): 873-874. doi:10.1038/35091139 norell2001a
  4. Lee, H. J.; Lee, Y. N.; Adams, T. L.; Currie, P. J.; Kobayashi, Y.; Jacobs, L. L.; Koppelhus, E. B. (2018). Theropod trackways associated with a Gallimimus foot skeleton from the Nemegt Formation, Mongolia. Palaeogeography, Palaeoclimatology, Palaeoecology 494: 160-167. doi:10.1016/j.palaeo.2017.10.020 lee2018a
  5. Gradziński, R.; Jerzykiewicz, T. (1974). Sedimentation of the Barun Goyot Formation. Palaeontologia Polonica 30: 111-146.

    Formalizes the Nemegt Formation, with Tsagaan Khushuu among its type sections, superseding the Upper Nemegt Beds of the describing paper.

    gradziński1974a