ACKNOWLEDGMENTS
We would like to thank J. Meng, R. O’Leary, and A. Gishlick for recataloging the camelid material at the AMNH, M. Emery for photographing the equid material for our reference, and M. Woodburne and P. Holroyd for constructive comments. N. A. F. was supported by a Geological Society of America Graduate Student Research Grant and the Paleontological Society Richard K. Bambach Award on this particular research trip.