In this project, the investigators will use a recently discovered, diverse, terrestrial microvertebrate fossil assemblage, found in the Naashoibito Member of the Kirtland Formation, in the San Juan Basin of New Mexico, to test the following hypotheses: (1) that there was mammalian faunal provinciality in the latest Cretaceous of North America, and; (2) that recovery faunas of earliest Cenozoic North America are derived at least in part from diverse provinces present in Late Cretaceous North America. Terrestrial ecosystem recovery following the end-Cretaceous mass extinction is best known from studies of the North American Western Interior. This recovery is typified by the appearance of mammals whose lineages are unknown from North America in the preceding Late Cretaceous period. That may be because knowledge of latest Cretaceous mammalian faunas has been geographically restricted to the northern region of the Western Interior. In collecting this new, southern fauna, better establishing the age of the Naashoibito Member, and incorporating this new fauna in analyses of existing phylogenetic and biogeographic data bases, the investigators will advance understanding of how biogeographic factors preceding the most recent mass extinction contributed to the subsequent recovery of terrestrial ecosystems. A secondary goal of this project is undergraduate education through involvement in original research, directed in part toward Native American students. The Kirtland Formation outcrops along the edge of the Navajo (Dine) Nation; this project offers an unique opportunity to educate Dine students in the geological history and vertebrate fossil resources of this part of their homeland, as well as in field and laboratory research methods. The findings of this project will be integrated into undergraduate geoscience curricula for science majors and pre-service K-12 teachers in the region.
