Hopkins, Samantha2010-09-292010-09-292010-09-29https://hdl.handle.net/1794/10750These are two updated data files, one appendix with a character matrix that corrects an error in the one originally published with the paper and one a figure illustrating character changes across the phylogeny for which the figure was left out although the figure caption was published.Athough over a hundred species of fossil aplodontoids have been described since the extant species, Aplodontia rufa (the mountain beaver), was first described by Rafinesque in 1817, a thorough survey of the relationships among all the species in this clade has not been undertaken since McGrew’s study in 1941. Here, a complete phylogenetic analysis of all published species of aplodontoids is used to reconstruct the evolutionary relationships within the clade, and to present an updated classification of the Aplodontoidea. Several of the traditionally recognized subfamilies are found to be paraphyletic, namely the Prosciurinae, the Allomyinae, and the Meniscomyinae. Others, however, including the Aplodontinae and the Mylagaulidae, appear to be monophyletic. These latter two taxa, which include all of the hypsodont members of the aplodontoid clade, seem to be sister taxa. The history of the aplodontoid clade shows several episodes of rapid diversification in the Early Oligocene, the Late Oligocene, and the Early to Middle Miocene. The Ansomyinae and Aplodontinae show comparatively low speciation rates. The patterns of change in morphology and evolutionary rates suggest a need for a more detailed study of the causes of diversification, extinction, and ecological change in this lineage.en-USAplodontidaeMylagaulidaeSystematicsCladisticsAplodontiaPaleontologyParsimonyProtrogomorphAplodontoideaFossilDataset