Phylogenomics Reveal the Historical Biogeography and Multiple Transcontinental Dispersals of the Amphitropical Harvester Ant Genus <i>Pogonomyrmex</i>

ABSTRACT Aim The harvester ant genus Pogonomyrmex has an amphitropical desert distribution, with high species diversity in arid regions of North America, South America and Hispaniola, and low species diversity in mesic regions. Here, we examine the historical biogeography of Pogonomyrmex to understand how the genus established its current distribution, with a focus on the origins of its amphitropical desert distribution and its spread to Hispaniola. Location North America, South America and Hispaniola. Methods We inferred a new phylogeny of Pogonomyrmex using ultraconserved elements (UCEs); we included duplicate samples of several species to test for species monophyly and evolutionary relationships within the genus. We used this phylogeny and geographic range data of extant Pogonomyrmex to reconstruct the ancestral ranges and transcontinental dispersals of the genus. Additionally, we used a time‐stratified ancestral range reconstruction to test if Pogonomyrmex may have utilized the hypothesized GAARlandia land bridge for dispersals to Hispaniola and North America. Results Our ancestral range reconstruction infers that the last common ancestor of Pogonomyrmex lived in northern South America during the middle Eocene. We infer that Pogonomyrmex dispersed from South America to North America twice, first in the Eocene and again in the Eocene or Oligocene. Results of our time‐stratified ancestral range reconstruction suggested that Pogonomyrmex did not disperse over the GAARlandia land bridge; we instead infer that Pogonomyrmex dispersed over the Central American Seaway to North America on both occasions and was potentially aided by the pre‐isthmus Panama Arc. Further, we infer that Pogonomyrmex dispersed to Hispaniola from North America or Central America during the Oligocene or Miocene. Main Conclusion This work adds to the growing body of literature that suggests that invertebrates were dispersing between North America and South America well before complete closure of the Isthmus of Panama, and that long‐distance dispersal played a significant role in the origins of desert biodiversity in North and South America.