We thank R. Kityo, Makerere University, and E. Musiime, Uganda Museum, for their help with logistics, fieldwork, and research in Kampala. This research would not have been possible without the permission and generous cooperation of the Uganda National Council for Science and Technology and the Commissioner of Antiquities, E. Kamuhangire, of the Uganda National Museum. We are indebted to the late W. Downs, our friend and former collaborator on the Ugandan rodents. L. MacLatchy thanks the Leakey Foundation, Wenner-Gren Foundation, and NSF (grant BCS-0215877) for financial support of this project. W. Downs drew Figure 1. R. Beavers (Southern Methodist University) took the scanning electron photomicrographs of the specimens. We greatly appreciate the careful reviews of the manuscript by P. Holroyd and L. Flynn.