ADDITIONAL ALBERTOSAURUS SARCOPHAGUS (TYRANNOSAURIDAE, ALBERTOSAURINAE) MATERIAL FROM THE DANEK BONEBED OF EDMONTON, ALBERTA, CANADA WITH EVIDENCE OF CANNIBALISM.

Abstract

Albertosaurus sarcophagus specimens from the Danek Bonebed of Edmonton, Alberta, Canada were first described in 2014. Since this initial report, the University of Alberta’s annual field work has continued to yield additional tyrannosaurid material from the Danek Bonebed. In addition to nearly 200 tyrannosaurid shed teeth, five diagnostic tyrannosaurid cranial and postcranial bones have been identified to date. Three cranial bones were included in the initial description; here the newly uncovered left and right tyrannosaurid pubes (UALVP 52709 and UALVP 56262 respectively) are described and mapped in relation to the previously known material. The pubes can be confidently diagnosed as tyrannosaurid based on a posterior bow of the pubic shaft and further classified as albertosaurine by a weakly expanded obturator plate. A. sarcophagus is the only tyrannosaurid and albertosaurine known from the Horseshoe Canyon Formation, which allows for the material to be confidently assigned to this taxon. The left pubis (UALVP 52709) possesses multiple tooth traces on the medial surface that were likely made post-mortem as the medial surface of the pubis would have been deep within the body cavity of the animal and reactive (healing) bone is absent. Given the numerous large gouge-like tooth traces on the medial surface of the pubis and the abundance of cf. Albertosaurus teeth from the bonebed it seems likely that an A. sarcophagus took this opportunity to feed on a conspecific; providing evidence for the first case of cannibalism from an albertosaurine.