1. Department of Earth Sciences, Denver Museum of Nature & Science, Denver, Colorado 80205, U.S.A.,
2. Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York 11794-8081, U.S.A.
3. Department of Anatomy, New York Institute of Technology, College of Osteopathic Medicine, Old Westbury, New York 11568, U.S.A.,
4. Section of Mammals, Carnegie Museum of Natural History, 5800 Baum Boulevard, Pittsburgh, Pennsylvania 15206, U.S.A.,
5. Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky 40202, U.S.A.,