Dr. Bill Wall and Mr. Vincent Santucci (National Park Service) have made considerable progress on background research for a book compiling all of the information available on vertebrate faunas of North America during the Oligocene (approximately 32 to 25 million years ago). I will draw heavily on Georgia College & State University's fossil collection for virtually every aspect of this work (including anatomical descriptions, systematic analyses, and illustrations for the book). Each field season we have added new taxa to our collection. The more time we spend in Badlands the greater our chances of finding rare organisms.

Paleoecological Analyses of the Badlands Microvertebrate Community.

Three ongoing projects are: rodent fauna; non-rodent micromammals; and herpetofauna. One of the goals of our previous field work was to search more thoroughly for microvertebrates (small mammals, lizards, snakes, and amphibians). Looking for small specimens, often much less than one centimeter long, is a difficult job, but each year we increase the significance of our microfauna collection. As usual we will continue to search for small fossils throughout the Badlands section. One locality remains a primary interest, an isolated riparian sandstone in the Chadron beds (approximately 35 million years old). This site is important because of its early age and rarity of fossils from a river environment (most of the beds in the badlands preferentially preserve members of the terrestrial ecosystem). Study of this area would involve species level identification and analysis of relative abundance of all collected members of this locality in order to compare this fauna to other late Eocene microvertebrate faunas (possibly a future thesis project).

A biomechanical analysis of feeding adaptations in the hippo-like anthracotheres (Artiodactyla).

Anthracotheres are extinct relatives of the Hippopotamidae. These relatively large artiodactyls may have occupied a niche similar to that of moose and other marginally aquatic ungulates. Anthracotheres can be found throughout the late Eocene to late Oligocene, but are typically restricted to sandstone facies. A similar lithologic association exists for the rhinocoerotoids Subhyracodon and Metamynodon. Possible niche overlap between these taxa leads to interesting questions about the ecological interactions between these early ungulates. We intend to compare the cranial and dental features of anthracotheres to their likely competitors using their presumed modern analogs as a control. This work should provide insight into niche evolution during the late Eocene - Oligocene (when the greatest faunal transition in Cenozoic mammalian history occurred).