Open Paleo

Albertosaurus

Osborn, 1905 al-BUHR-to-SAWR-us /ælˌbɜːrtəˈsɔːrəs/

Named after Alberta, Canada, combined with Greek 'sauros' meaning 'lizard'; meaning 'Alberta lizard'

83.6–66.0 million years ago Campanian–Maastrichtian, Late Cretaceous
Late Cretaceous stages

Albertosaurus is a genus of large tyrannosaurid theropod dinosaur that lived in northwestern North America during the early to middle Maastrichtian age of the Late Cretaceous period, about 71 million years ago. The type species, A. sarcophagus, was apparently restricted in range to the modern-day Canadian province of Alberta, after which the genus is named, although an indeterminate species ("cf. Albertosaurus sp.") has been discovered in the Corral de Enmedio and Packard Formations of Mexico. Scientists disagree on the content of the genus and some recognize Gorgosaurus libratus as a second species.

Diagnosis

  1. Mandibular ramus devoid of triangular osseous plates between the teeth
  2. Anterior truncate teeth reduced to a single small pair
  3. Fifteen mandibular teeth, including one small anterior tooth truncated posteriorly
  4. Reduced alveolar partitions between the mandibular teeth; principal alveolar grooves on inner surface of outer dentary wall with little or no development of grooves on alveolar plate
  5. Skull with two preorbital openings; lower jaw with a distinct presplenial
  6. Teeth laterally compressed, lenticular in section, upper portion more rounded oval, near bases recurved, serrate on both borders

Species

Albertosaurus sarcophagus Osborn, 1905

Type species

From Ancient Greek term 'sarkophagos', meaning 'flesh-eating', combining the Greek words 'sarx' ('flesh') and 'phagein' ('to eat').

Holotype
CMN 5600 , Canadian Museum of Nature
Material
Skull (CMN 5600); cotype a smaller skull.
Horizon
Horseshoe Canyon Formation, Campanian–Maastrichtian, Late Cretaceous , 83.6–66.0 million years ago
Locality
Knee Hills Creek, Red Deer River, Alberta, Canada Russell (1970) places the holotype in Member A of the lower Edmonton Formation and the paratype CMN 5601 in Member B, so the type series comes from two different stratigraphic levels. None of the works cited for this taxon correlates those lettered members with the seven named members Eberth and Braman (2012) erected in their place. The Albertosaurus bonebed at Dry Island Buffalo Jump does sit in the Tolman Member, but that is referred material from well above the type locality.

Notable specimens

  • ROM 807

    Royal Ontario Museum Found 1923 by Gus Lindblad, Ralph Hornell pathology

    Skull-less partial skeleton, originally the holotype of A. arctunguis (later referred to A. sarcophagus). Notable for pathologies: a deep hole in the iliac blade and exostosis on the fourth left metatarsal. Also studied for stress fractures.

    Molnar (2001)

  • TMP 2022.007.0040

    Royal Tyrrell Museum of Paleontology ontogeny

    The smallest associated Albertosaurus skull described, from an immature individual at least eight years old and about 6 meters long. Unhealed tooth marks on its lower jaw, most consistent with a dromaeosaurid, are the first documented evidence of a dromaeosaurid feeding on a tyrannosaurid.

    Doyon et al. (2026)

References

  1. Osborn, H. F. (1905). Tyrannosaurus and other Cretaceous carnivorous dinosaurs. Bulletin of the American Museum of Natural History 21(14): 259-265. doi:10.5281/zenodo.814935 osborn1905a
  2. Molnar, R. E. (2001). Theropod paleopathology: a literature survey. Mesozoic Vertebrate Life: New Research Inspired by the Paleontology of Philip J. Currie (Tanke, D. H.; Carpenter, K., eds.) 337-363. Indiana University Press, Bloomington. molnar2001a
  3. 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 preserved scale impressions from the gastral region of the holotype.

    hendrickx2022a
  4. 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
  5. Eberth, D. A.; Braman, D. R. (2012). A revised stratigraphy and depositional history for the Horseshoe Canyon Formation (Upper Cretaceous), southern Alberta plains. Canadian Journal of Earth Sciences 49(9): 1053-1086. Canadian Science Publishing. doi:10.1139/e2012-035 eberth2012a
  6. Doyon, J. A.; Brown, C. M.; Therrien, F.; Currie, P. J. (2026). Evidence for dromaeosaurid scavenging on Albertosaurus (Dinosauria: Tyrannosauridae). Journal of Paleontology 1-21. doi:10.1017/jpa.2026.10269 doyon2026a