October 7 2009

12:00 LSB 2320

Blaire Van Valkenburgh
Department of Ecology and Evolutionary Biology, UCLA

Cracked Teeth and Complicated Noses


Research in my lab spans a wide range of topics, from ecological relationships within extinct predator-prey systems to the function of the mammalian skull. Underlying all this diversity is the quest to extract new, biologically significant information from fossil vertebrates. In this talk, I will describe two disparate projects, the first is an exploration of respiratory and olfactory turbinate form and function in carnivores, and the second examines the potentially far-reaching implications of high dental fracture rates in Pleistocene large carnivores. The turbinates are bony scrolls within the nasal chamber of mammals that are involved in olfaction, heat and water conservation. Using high resolution CT scans of skulls, we are able to visualize the turbinates and quantify their dimensions, such as surface area and chamber volume. Comparisons of marine and terrestrial carnivores reveal dramatic differences across the order Carnivora, with marine species in three families having greatly expanded respiratory turbinates alongside reduced olfactory turbinates, reflecting the greater demands of heat and water conservation in aquatic environments.

The tooth fracture study relies on extensive collections of Pleistocene megafauna, such as the Rancho La Brea tar seeps and the Alaskan permafrost deposits, and includes extinct species such as sabertooth cats, dire wolves, and American lions. The Pleistocene species exhibit dental fracture rates that are 2-5 times that of their extant counterparts, and this likely reflects an increased consumption of bone. This in turn implies much greater densities of large carnivores in the past and has implications for the late Pleistocene extinction event as well as for defining restoration goals for modern predator-prey ecosystems.















































































































































































































































































































































































































































































































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