1. Department of Earth Sciences, University of Oxford, Parks Road, Oxford OX1 3PR, UK.
2. Environmental Science Program and Department of Biological Sciences, DePaul University, 2325 North Clifton Avenue, Chicago, IL 60614, USA.
3. Sternberg Museum of Natural History, Fort Hays State University, 3000 Sternberg Drive, Hays, KS 67601, USA.
4. Natural History Museum and Biodiversity Research Center, University of Kansas, 1345 Jayhawk Boulevard, Lawrence, KS 66045, USA.
5. Division of Ecology and Evolutionary Biology, Faculty of Biomedical and Life Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK.
6. Triebold Paleontology and Rocky Mountain Dinosaur Resource Center, 201 South Fairview Street, Woodland Park, CO 80863, USA.