ACKNOWLEDGEMENTS

We would like to thank Dr. Don Brinkman and Brandon Strilisky for allowing access to the Royal Tyrrell Museum collections and exhibits, including the assets at the Dinosaur Provincial Park Field Station. We also thank Dr. Brinkman for stimulating discussions and for the opportunity to present an early version of this work. Dr. Craig Scott, Dr. Nick Longrich, Caleb Brown, Patrick Wise, Danielle Fraser and Dr. A. P. Russell provided access to specimens in their keeping, and made many valuable suggestions.