METHODS AND MATERIALS

All of the small mammals (about 2,500 identifiable specimens) collected during this study were identified by the author and compared with the small mammals collected from the Panaca Fm. by Galusha and Emry for the AMNH. All specimens listed below in materials examined are from the UALP collection unless indicated otherwise. Due to the limit of this paper, description of the largest group, the cricetids, is reported in Mou (this volume).

Most of the identified small mammals are isolated teeth that were picked from fine or coarse concentrate after multiple washing of sediment in screen boxes. Specimens were mounted (using polyvinyl acetate dissolved in acetone) on the head of a half-inch straight pin embedded into a small cork, to facilitate handling and measurement; a half-dram glass vial was placed over the pin for safety in storage. Measurements were made to the nearest 0.01 mm with the aid of a reticule mounted in a microscope. All measurements are maximum dimensions regardless of wear, and transverse dimensions are perpendicular to anteroposterior dimensions. When applicable, the means, standard deviations and coefficients of variance were computed for each sample. Dental terminology follows Korth (1994) unless differences are noted and discussed in the text. Upper teeth are abbreviated with capital letters (e.g., M1) and lower teeth are abbreviated with lower case letters (e.g., m1).

Institutional abbreviations are: American Museum of Natural History (AMNH), Frick Laboratory of American Museum of Natural History (F:AM), University of Kansas (KU), San Bernardino County Museum (SBDM), University of Arizona Laboratory of Paleontology (UALP), University of Michigan Museum of Paleontology (UMMP), U.S. Geological Survey (USGS). Locality data are available to qualified researchers from the Department of Geosciences, University of Arizona, which is the repository for all UALP specimens. In the Materials examined sections, the acronym UALP has been removed to save space.