Ph.D. Candidate University of California Davis, California
Dorymyrmex Mayr 1866, the “pyramid ants” or “cone ants,” are conspicuous inhabitants of arid landscapes across the Americas, found primarily in the temperate regions north and south of the tropics. Despite being frequently collected and ecologically important, they exemplify the taxonomic neglect typical in the subfamily Dolichoderinae. By targeting ultraconserved elements (UCEs) across the genome, I have constructed an alignment of 1891 genetic loci and inferred phylogenies using a variety of methods. The three major clades of Dorymyrmex that arise correspond both to previous, morphologically defined conceptions of the genus and to geographical distribution. One clade in particular, the pyramicus group, is enormously widespread but shows minimal morphological differentiation—a major reason that the genus has been neglected by traditional taxonomy. I characterize this radiation, explore methods that may help increase its resolution, and ponder what species delimitation in this group may entail. Finally, I present my observations on biogeography: a general south-to-north dispersal pattern, with an intercontinental transition that occurred between the Miocene and Pleistocene, i.e., when North and South America were not connected, a pattern seen in other arid-adapted amphitropical New World taxa. Characterizing these groups and the difficulty of this largely Nearctic radiation is an important first step in resolving the taxonomic puzzle of Dorymyrmex ants, which have garnered attention from many angles, including behavior, chemical ecology, and physiology.
