Split Carinae on Tyrannosaurid Teeth and Implications of Their Development

Examination of hundreds of shed and intact tyrannosaurid teeth from several taxa and formations revealed that the presence of split carinae is widespread. Approximately 11% of the surveyed teeth showed some degree of expression of this trait. Split carinae were found in Tyrannosaurus rex, Daspletosaurus sp., Albertosaurus sp., and Alectrosaurus olsoni. The trait is also found in non-tyrannosaurids (e.g., Allosaurus fragilis). Trauma, aberrant tooth replacement, or genetic factors may have led to the development of split carinae, although the latter finds the most support. If the split carinae are caused by genetic factors, they may prove valuable in assessing the dispersion patterns and evolution of the tyrannosaurids.