[D] Appalachiosaurus montgomeriensis [Su] [sG] [T]
Carr, Williamson, Schwimmer, 2005
Cretaceous Late, Campanian
Saurischia Theropoda Tyrannosauria Tyrannosauridae
Demopolis Chalk, Montgomery County, Alabama, Georgia, US
Genus - Typespecies - Skull
Based on the partial skeleton of a partially-grown individual, including a partial skull (the biting portion, mostly), much hindlimb material, parts of the lower pelvic bones, and a few caudals (including two that are fused). Appalachiosaurus was smaller and more primitive than Tyrannosaurus rex and had a narrower snouth. Autapomorphies include a wide jugal process of the ectopterygoid, a caudal pneumatic foramen of the palatine that pierces the rostral half of the vomeropterygoid process of the bone, an articular surface for the lacrimal on the palatine that is distally positioned on the dorsolateral process, and pedal unguals that have a distinct proximodorsal lip over the articular surface.
Etymology genus: Appalachio-, for the occurrence of the specimen in eastern North America during the Late Cretaceous; -sauros, Greek, meaning lizard. Species: Named for Montgomery County, Alabama, where the type locality is located; -ensis, Latin, meaning from.
Diagnosis: Tyrannosauroid possessing the following autapomorphies: wide jugal process of ectopterygoid; caudal pneumatic recess of palatine situated rostral to caudal margin of vomeropterygoid process; articular surface for lacrimal of palatine situated distally; and prominent lip extending over dorsal margin of articular surface of pedal unguals.
Holotype: Incomplete skull and skeleton, RMM 6670 (McWane Center, Birmingham, Alabama).
Locality and Horizon: The Turnipseed Dinosaur site was reportedly 9.7 meters above the basal conglomerate of the Demopolis Formation, in a marl and calcareous clay stratum (King et al., 1988). The site is 1.77 km north of US Highway 82 at the Downing Crossroads; SE1/4, NE1/4, NE1/4, Sec. 35, T14N, R20E; in Montgomery County, Alabama. The age is determined as 78 million years (Ma) based on stratigraphic position and nannofossil biostratigraphy (see Chronostratigraphy).