@article {33493, title = {Unraveling the evolutionary history of the hyperdiverse ant genus Pheidole (Hymenoptera: Formicidae)}, journal = {Molecular Phylogenetics and Evolution}, volume = {48}, year = {2008}, month = {Jan-07-2008}, pages = {224 - 239}, abstract = {

Pheidole\ is currently the most species rich genus of ants in the world, with many taxa still awaiting description. In this study, I reconstruct the phylogeny of\ Pheidole\ using molecular characters from three mitochondrial genes and two nuclear genes for \∼140 species. The phylogenetic relationships of\ Pheidole\ are investigated with special interest in understanding factors that may have led to their remarkable diversity. The results presented here establish a framework for understanding the explosive radiation of this group by providing (1) a phylogenetic estimate, and (2) a comparative analysis of life history traits that are likely to have been important in the diversification of the group. In all analyses,\ Pheidole\ is recovered as a monophyletic lineage, and molecular clock estimates infer an age of 58.4\–61.2\ million years ago (Ma) for crown group members of the genus. Using an estimate of diversification rate, it appears that\ Pheidole\ has undergone 0.108\–0.103 speciation events per million years. Previous hypotheses of species groups were largely not upheld in the analyses presented here. Workers of the genus\ Pheidole\ are dimorphic with a minor and major (soldier) subcaste. A third subcaste of super majors is known in eight species of\ Pheidole\ and this trait was found to have arisen multiple times throughout the phylogeny. Seed harvesting is common among species of the genus and is thought to be one of the factors leading to the diversification of the group, but additional data will be required to further test this hypothesis. To address biogeographic questions on the origin of the genus, both New and Old World species were included in these analyses, and the results suggest that\ Pheidole\ is New World in origin with a possible single introduction into the Old World.

}, keywords = {Ants, Dimorphic, Hyperdiverse, Hypothesis testing, Key innovation, New World, Old World, Pheidole, Phylogeny, Seed harvesting, Trimorphic}, issn = {10557903}, doi = {10.1016/j.ympev.2008.02.020}, url = {http://linkinghub.elsevier.com/retrieve/pii/S1055790308000602}, author = {Moreau, Corrie S.} }