1. Department of Paleontology, Calvert Marine Museum, PO Box 97, Solomons, Maryland 20688, U.S.A.,
2. Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611, U.S.A.
3. Department of Geology, University of Florida, Gainesville, Florida 32611, U.S.A.,
4. National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560, U.S.A.
5. College of Computer, Mathematical and Natural Sciences, University of Maryland, College Park, Plant Sciences Building, College Park, Maryland 20742, U.S.A.,