In the eastern United States, 74 species of Anillini in two genera have been described, with most belonging to AnillinusCasey. Until now, no systematic framework has existed for this large genus, hampering integrative studies. Using DNA sequences from 98 Nearctic species, we present a well-resolved molecular phylogeny supporting a sound systematic framework. Twenty-one species groups of Anillinus are diagnosed, in part using newly recognized variation in the number of modified male protarsi and the state of the spermathecal duct. We present the first descriptions of Nearctic anilline larvae, which possess none of the synapomorphies of other anilline larvae. Within Anillinus, two major clades are mostly consistent with setation of the right paramere: a “hairy clade” with more than four setae, and a “quadrisetose clade.” Throughout the phylogeny, microhabitat use varies within each clade, and several endogean lineages are phylogenetically isolated. Our work increases the South Carolina fauna by nearly five-fold. Nine new species are described, Serranillus monadnock sp. n., Anillinus castaneus sp. n., Anillinus choestoea sp. n., Anillinus dentatus sp. n., Anillinus jancae sp. n., Anillinus mica sp. n., Anillinus micamicus sp. n., Anillinus seneca sp. n., and Anillinus simplexsp. n. Several species are newly reported, bringing the total to 20 described species representing seven species groups. Two endemic groups inhabit deep clay soils in the Piedmont and possess unique male sexual characters. The Anillini are a unique component of Nearctic biodiversity, with great potential as a model system for studies of biogeography, secondary male sexual modification, and endogean adaptations.

This dataset, consisting of two Nexus files, consists of DNA sequences that were obtained by Sanger sequencing by Psomagen, and trees resulting from Maximum likelihood analyses performed with IQ-TREE. Forward and reverse reads were sequenced, and assembled using Geneious. Chromatograms were studied in Geneious, and ambiguity codes were applied where double peaks were apparent. The sequences were trimmed and aligned in the program Mesquite. The Zephyr package in Mesquite was used to orchestrate maximum likelihood analyses using IQ-TREE.