Open Paleo

Chirostenotes

Gilmore, 1924 KY-roh-stin-OH-teez /ˌkaɪroʊstɪˈnoʊtiːz/

From Greek cheir meaning 'hand' and Greek stenos meaning 'narrow'. Full meaning: 'narrow-handed', referring to the narrow, slender hands of the fossil.

83.6–72.2 million years ago Campanian, Late Cretaceous
Late Cretaceous stages

Chirostenotes is a genus of oviraptorosaurian dinosaur from the late Cretaceous (about 76.5-75 million years ago) of Alberta, Canada. The type species is Chirostenotes pergracilis.

Diagnosis

  1. Manus anisotridactyl with marked inequality in digit lengths, intermediate between Ornitholestes and Struthiomimus but closer to the former.
  2. Distal ends of metacarpals I and II deeply grooved with keeled ginglymoid facets, confining digits to exclusive opening and closing movement.
  3. Proximal phalanx of digit II notably long and slender, exceeding that of Struthiomimus proportionally.
  4. Phalanges extremely long, slender, and highly pneumatic with thin bird-like walls and strongly compressed cross-section.
  5. Unguals compressed and strongly recurved, of raptorial type, closely resembling those referred to Coelurus gracilis.
  6. Dentary (referred specimen) very long and slender with at least 18 teeth — more than any other North American carnivorous dinosaur above the Triassic.

Species

Chirostenotes pergracilis Gilmore, 1924

Type species

From Latin, combining 'per-' meaning 'throughout' and 'gracilis' meaning 'gracile' or 'slender', describing the slender build of the animal.

Holotype
CMN 2367 , Canadian Museum of Nature
Material
Nearly complete articulated digits of both fore feet (both manus).
Horizon
Dinosaur Park Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
2 miles northeast of the mouth of Little Sandhill Creek, Red Deer River, Alberta, Canada

Synonyms of the genus

Name Type Reason
Macrophalangia junior subjective Additional material demonstrated that Macrophalangia and Chirostenotes represent the same animal, with Chirostenotes having priority.

References

  1. Gilmore, C. W. (1924). A new coelurid dinosaur from the Belly River Cretaceous of Alberta. Bulletin of the Canadian Department of Mines, Geological Survey 38: 1-12. Natural Resources Canada/CMSS/Information Management. doi:10.4095/105003 gilmore1924a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

    Source of the hip height estimate.

    jones2026c