1. Department of Geology and Geophysics; Yale University; New Haven CT 06511 USA
2. Division of Vertebrate Paleontology; Yale Peabody Museum of Natural History; New Haven CT 06511 USA
3. Department of Vertebrate Zoology; National Museum of Natural History, Smithsonian Institution; Washington DC 20560 USA
4. Department of Organismic and Evolutionary Biology; Harvard University; Cambridge MA 02138 USA
5. Department of Anatomy; New York Institute of Technology, College of Osteopathic Medicine; New York NY USA
6. Division of Paleontology; American Museum of Natural History; New York NY USA
7. Department of Geosciences; University of Tübingen; 72074 Tübingen Germany