This project will study the evolutionary relationships of treeshrews, an order (Scandentia) of squirrel-like mammals from Southeast Asia. Treeshrews have featured prominently in studies of mammalian evolution due to the belief that they represent one of the most primitive groups of placental mammals. Uncertainty about the number of species and their interrelationships is striking, however, and represents a significant impediment to their conservation and studies of mammalian diversification. This study will utilize material in museums worldwide to 1) obtain DNA sequences with which evolutionary relationships will be studied, 2) record anatomical data and 3) combine these data to study geographic variation and identify the number of living species. Southeast Asia is undergoing a conservation crisis, and the Indo-Malayan archipelago is one of the world's five hottest conservation hotspots. This study will have implications for conservation and understanding diversification in geographically complex environments. A postdoc will be trained in degraded DNA sequencing, and she will also engage in teaching and outreach. Two undergraduates will also be trained. A resulting database of treeshrew museum specimens and dissemination of information to the public via web sites will promote awareness of SE Asian biodiversity. Presentations and publications will enhance understanding of treeshrew diversification and SE Asian biogeography. Benefits to society include more informed conservation priorities and increased awareness of the value of museum collections.