Open Paleo

Appalachiosaurus

Carr et al., 2005 AP-uh-LAY-chee-oh-SOR-uhs /ˌæpəˌleɪtʃioʊˈsɔːrəs/

Named for the Appalachian region of eastern North America where it was found, combined with Greek 'sauros' meaning 'lizard', meaning 'Appalachian lizard'.

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

Appalachiosaurus is a genus of tyrannosauroid theropod dinosaur from the Late Cretaceous period of what is now eastern North America. It was a basal member of the clade Eutyrannosauria, meaning it was rather close in relation to the true tyrannosaurids such as Tyrannosaurus. Like most theropods, it was a bipedal predator. Only a juvenile skeleton has been found, representing an animal approximately 6.5 meters (21 ft) long and weighing 623 kilograms (1,373 lb), which indicates an adult would have been significantly larger.

Diagnosis

  1. Wide jugal process of ectopterygoid, elongate and straightened rather than short and strongly backswept as in other tyrannosauroids
  2. Caudal pneumatic recess of palatine situated rostral to caudal margin of vomeropterygoid process
  3. Articular surface for lacrimal of palatine situated distally on the dorsolateral process
  4. Prominent lip extending over dorsal margin of articular surface of pedal unguals, creating a concave 'lipped' appearance cranial to the proximal articular surface

Species

Appalachiosaurus montgomeriensis Carr et al., 2005

Type species

Named for Montgomery County, Alabama, where the holotype was discovered.

Holotype
RMM 6670 , McWane Science Center
Material
Incomplete skull and skeleton
Horizon
Demopolis Chalk Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
Turnipseed Dinosaur site, Alabama, United States

References

  1. Carr, T. D.; Williamson, T. E.; Schwimmer, D. R. (2005). A new genus and species of tyrannosauroid from the Late Cretaceous (Middle Campanian) Demopolis Formation of Alabama. Journal of Vertebrate Paleontology 25(1): 119-143. Informa UK Limited. doi:10.1671/0272-4634(2005)025[0119:angaso]2.0.co;2 carr2005a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

    Source of the hip height estimate, and the appearance features.

    jones2026c