Open Paleo

Gorgosaurus

Lambe, 1914 GOR-guh-SOR-uhs /ˌɡɔːrɡəˈsɔːrəs/

From Greek gorgos (dreadful, fierce) and sauros (lizard); meaning 'dreadful lizard'

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

Gorgosaurus is a genus of tyrannosaurid theropod dinosaur that lived in western North America during the Late Cretaceous Period (Campanian), between about 76.5 and 75 million years ago. Fossil remains have been found in the Canadian province of Alberta and the U.S. state of Montana. Paleontologists recognize only the type species, G. libratus, although other species have been erroneously referred to the genus.

Diagnosis

  1. First maxillary tooth similar in shape and size to premaxillary teeth, unlike other known Cretaceous carnivorous dinosaur genera
  2. Premaxillary teeth long and slender with a keel on each side of a slightly convex lingual surface, laterally compressed with fore-aft diameter slightly greater than breadth
  3. No triangular alveolar plates on the inner sides of the jaws
  4. A foramen present in the surangular, positioned far back and near its upper border; no presplenial
  5. Manus reduced to two digits (II and III) with metacarpal IV represented only by a proximal vestigial bone; humerus twice the length of the ulna
  6. Metatarsal III nearly two-thirds the length of the femur; metatarsal I represented distally by a short vestigial bone giving digit I a forwardly directed position

Species

Gorgosaurus libratus Lambe, 1914

Type species

From Latin 'libratus', the past participle of 'librare' meaning 'to balance', likely referring to the animal's balanced build.

Holotype
NMC 2120 , Canadian Museum of Nature
Material
Nearly complete skeleton including skull, most of vertebral column, pectoral and pelvic arches, complete fore-limb, both complete hind-limbs, ribs, and entire abdominal rib series; cervicals and tail tip absent
Horizon
Dinosaur Park Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
3.5 miles below the mouth of Berry Creek, south side of the Red Deer River, Alberta, Canada Lambe (1914) names only the Belly River formation, which predates its division; Brochu (2003) places the holotype in the Dinosaur Park Formation. Russell (1970) gives the site as Sternberg's quarry 36, the only quarry number published for this specimen.

Notable specimens

  • TMP 2009.012.0014

    Royal Tyrrell Museum of Paleontology gut contents

    Juvenile Gorgosaurus preserving in situ stomach contents of two roughly one-year-old Citipes juveniles, with only their hindlimbs and caudal vertebrae present. Provides direct dietary evidence reinforcing the theory of an ontogenetic dietary shift in tyrannosaurids.

    Therrien et al. (2023)

  • TCMI 2001.89.1

    The Children's Museum of Indianapolis pathology

    Specimen from Montana showing severe pathologies: healed leg, rib, and vertebral fractures, osteomyelitis at the tip of the lower jaw resulting in permanent tooth loss, and possibly a brain tumor.

    Pickrell (2003)

  • TMP 1991.036.0500

    Royal Tyrrell Museum of Paleontology pathology

    Very complete sub-adult preserving face-bite injuries, a thoroughly healed right fibula fracture, a healed dentary fracture, and a mushroom-like hyperostosis of a right pedal phalanx; preserved in a characteristic death pose.

    Rothschild et al. (2001)

References

  1. Lambe, L. M. (1914). On a new genus and species of carnivorous dinosaur from the Belly River Formation of Alberta, with a description of the skull of Stephanosaurus marginatus from the same horizon. The Ottawa Naturalist 28: 13-20. lambe1914a
  2. Hendrickx, C.; Bell, P. R.; Pittman, M.; Milner, A. R. C.; Cuesta, E.; O'Connor, J.; Loewen, M.; Currie, P. J.; Mateus, O.; Kaye, T. G.; Delcourt, R. (2022). Morphology and distribution of scales, dermal ossifications, and other non-feather integumentary structures in non-avialan theropod dinosaurs. Biological Reviews 97(3): 960-1004. doi:10.1111/brv.12829

    Documents faint polygonal scale impressions between the caudal chevrons.

    hendrickx2022a
  3. Therrien, F.; Zelenitsky, D. K.; Tanaka, K.; Voris, J. T.; Erickson, G. M.; Currie, P. J.; DeBuhr, C. L.; Kobayashi, Y. (2023). Exceptionally preserved stomach contents of a young tyrannosaurid reveal an ontogenetic dietary shift in an iconic extinct predator. Science Advances 9(49): eadi0505. doi:10.1126/sciadv.adi0505 therrien2023a
  4. Pickrell, J. (2003). First dinosaur brain tumor found, experts suggest. National Geographic News.

    Online news article reporting the pathologies of TCMI 2001.89.1.

    pickrell2003a
  5. Rothschild, B.; Tanke, D. H.; Ford, T. L. (2001). Theropod stress fractures and tendon avulsions as a clue to activity. Mesozoic Vertebrate Life: New Research Inspired by the Paleontology of Philip J. Currie (Tanke, D. H.; Carpenter, K., eds.) 331-336. Indiana University Press, Bloomington. rothschild2001a
  6. Brochu, C. R. (2003). Osteology of Tyrannosaurus rex: insights from a nearly complete skeleton and high-resolution computed tomographic analysis of the skull. Society of Vertebrate Paleontology Memoirs 7: 1-138. doi:10.2307/3889334

    Places the holotype in the Dinosaur Park Formation, the assignment the describing paper predates.

    brochu2003a
  7. Olshevsky, G.; Ford, T. L.; Yamamoto, S. (1995). The origin and evolution of the tyrannosaurids (Part 1). Kyoryugaku Saizensen 9: 92-119.

    Places the quarry high at prairie level on the south bank of the Red Deer River, 3.5 miles below the mouth of Berry Creek.

    olshevsky1995a
  8. Russell, D. A. (1970). Tyrannosaurs from the Late Cretaceous of western Canada. Publications in Palaeontology 1. National Museum of Natural Sciences, Ottawa. doi:10.5281/zenodo.1040973 russell1970a