Molecular systematics of Dipodomys elator

The Texas kangaroo rat, Dipodomys elator, has an extremely restricted distribution in northern Texas and south-central Oklahoma. Dipodomys elator has been studied extensively; however, its phylogenetic status within the genus Dipodomys remains unclear. Previous systematic analyses, including morphometric, allozymic, and cytogenetic studies, have produced conflicting results as to the relationship of this species to other kangaroo rats. In this study, the phylogenetic relationships of Dipodomys elator to other closely related taxa in the genus Dipodomys (D. merriami, D. phillipsii, D. ordii, D. spectabilis, and D. nelsoni) were examined using the nucleotide sequence variation within the cytochrome b gene (1143) from the mitochondrial genome. The phylogenetic analyses suggest that D. elator is most closely related to D. phillipsii, and both of these species form a monophyletic assemblage with D. merriami. Based on the sequence divergence, there was a diversification within the genus near the end of the Pliocene epoch. The results of this study are compared to the previous systematic studies and the natural history information of D. elator is summarized.