The relationships among the placental mammals are poorly understood at the ordinal level. This study will employ enzymatic amplification (polymerase chain reaction) and nucleotide sequencing of the mitochondrial cytochrome oxidase subunit II gene in a number of eutherian orders. Specifically, the postulated superorders Archonta (comprised of primates, tree shrews, bats, and flying lemurs) and Glires (rodents, rabbits, and pikas) will be examined in detail. In addition, this gene will be sequenced in potential sister taxa to some of these orders, such as insectivores and elephant shrews. Interordinal variation will be assessed for each group and hypotheses of relationship will be based upon the identification of shared, derived characters (synapomorphies) using an armadillo and pangolin as outgroup taxa. The results of this study should provide a strong framework within which to interpret the radiation of a flying-gliding lifestyle in eutherians and the unique cranial traits of rodents and rabbits.
