Phylogeny of the Leptanillinae (Hymenoptera: Formicidae), reciprocally illuminated by phylogenomics and male morphology

The subfamily Leptanillinae (Hymenoptera: Formicidae) consists of minute, subterranean ants, and is sister to nearly all other ants. Male specimens are acquired more easily than workers, and the sexes are almost never collected in association: many subclades of the Leptanillinae are known solely from male specimens. Thus, our understanding of these intriguing ants was shackled by parallel taxonomy. My PhD dissertation aimed to delimit taxa within the Leptanillinae that are reciprocally monophyletic, and uniformly diagnosable based upon both workers and males. To this end, I used phylogenomic inference from ultra-conserved elements (UCEs); and employed Bayesian total-evidence inference to resolve the phylogenetic position of the aberrant genus Scyphodon, for which molecular data are unavailable. With UCEs, I definitively identified the worker of two speciose subclades in which that caste was heretofore unknown (Yavnella and Noonilla), bypassing the need for collection of workers and males together for these to be associated, while total-evidence inference resolved the placement of Scyphodon with high probability. The higher taxonomy of the Leptanillinae now reflects evolutionary relationships, with phylogeny integrating phenotypic observations of both males and workers. With their systematics now resolved, I will attempt divergence dating of the Leptanillinae by Bayesian inference under the fossilized birth-death (FBD) model, despite the total lack of leptanilline fossils—a challenge I hope to overcome by extensive outgroup sampling.