PALEONTOLOGICAL METHODS

All cited fossil localities in Garfield and western McCone counties are cataloged in the records of the University of California Museum of Paleontology (UCMP) and their identifying numbers presented in the following format: V-73080. Catalog numbers of individual specimens are preceded by their museum acronyms (see abbreviations). Online locality and specimen catalogs are available on the UCMP website. Measurements of specimens were obtained with dial calipers and recorded to the nearest tenth of a millimeter. Ages cited in the text are taken from Wilson (2004, 2005) who recalculated the values for tephra presented in Swisher et al. (1993) and magnetostratigraphic chron boundaries published by Berggren et al. (1995). Following Renne et al. (1998) and Knight et al. (2003 erratum), the value of 65.58 ± 0.04 m.y. was adopted for the Cretaceous/Tertiary boundary, and their conversion formula was used to recalculate the other age determinations.

Institutional Abbreviations

AMNH – American Museum of Natural History, New York, New York; LSUMG – Louisiana State University, Museum of Geosciences, Baton Rouge, Louisiana; LACM – The Natural History Museum of Los Angeles, California; NMMNH – New Mexico Museum of Natural History and Science, Albuquerque, New Mexico: PU – Princeton University, specimens now in the collections of the Yale Peabody Museum, New Haven, Connecticut; UCMP – University of California Museum of Paleontology, Berkeley, California; UMVP – The Museum of Paleontology, University of Minnesota, Minneapolis, Minnesota; UW – Collection of fossil vertebrates, departmental scientific collections, Department of Geology and Geophysics, The University of Wyoming, Laramie, Wyoming.