1. Department of Anatomy, College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, New York 11568, U.S.A.,
2. Department of Anthropology, University of Texas at Austin, Austin, Texas 78712, U.S.A.,
3. Vertebrate Paleontology Laboratory, Jackson School Museum of Earth History, University of Texas at Austin, Texas 78712, U.S.A.