Phylogenomic species delimitation, taxonomy, and "bird guide" identification for the Neotropical ant genus Rasopone (Hymenoptera: Formicidae)

Authors: LONGINO, JOHN - University Of Utah; Branstetter, Michael

Submitted to: Insect Systematics and Diversity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/9/2020
Publication Date: 4/11/2020
Citation: Longino, J.T., Branstetter, M.G. 2020. Phylogenomic species delimitation, taxonomy, and "bird guide" identification for the Neotropical ant genus Rasopone (Hymenoptera: Formicidae). Insect Systematics and Diversity. 4(2). https://doi.org/10.1093/isd/ixaa004.
DOI: https://doi.org/10.1093/isd/ixaa004

Interpretive Summary: The genus Rasopone is a relatively understudied group of Neotropical ants whose species-level taxonomy is challenging and neglected. Little is known about the biology of this group because they occur in leaf litter and are most often collected only when using specialized sampling techniques. As a consequence, few species have been described, and reliable resources for species identification have been lacking. Using genome-scale molecular data and mitochondrial barcodes, combined with new collections, the authors analyzed many Rasopone samples from across Central and South America, as well as a select set of closely related ant genera. The molecular analyses revealed the existence of multiple new species and identified a subset of Rasopone species that actually belong to a different genus but were misidentified. Using the molecular results, the authors described 12 new species and created an identification guide to 15 named species plus an additional 12 morphospecies. The results present new insights into ant biodiversity in the Americas, provide new resources for identifying Rasopone ants, and demonstrate the utility of integrating genomic data into species-level taxonomic study.

Technical Abstract: Rasopone Schmidt & Shattuck is a poorly known lineage of ants that live in Neotropical forests. Informed by phylogenetic results from thousands of ultraconserved elements (UCEs) and mitochondrial DNA barcodes, we revise the genus, providing a new morphological diagnosis and a species-level treatment. Analysis of UCE data from many Rasopone samples and select outgroups revealed non-monophyly of the genus. Monophyly of Rasopone was restored by transferring several species to the unrelated genus Mayaponera Schmidt & Shattuck. Within Rasopone, species are morphologically very similar, and we provide a "bird guide" approach to identification rather than the traditional dichotomous key. Species are arranged by size in a table, along with geographic range and standard images. Additional diagnostic information is then provided in individual species accounts. We recognize a total of 15 named species, of which the following are described as new species: R. costaricensis, R. cryptergates, R. cubitalis, R. guatemalensis, R. mesoamericana, R. pluviselva, R. politognatha, R. subcubitalis, and R. titanis. An additional 12 morphospecies are described but not formally named due to insufficient material. Rasopone panamensis (Forel, 1899) is removed from synonymy and elevated to species. The following species are removed from Rasopone and made new combinations in Mayaponera: M. arhuaca (Forel, 1901), M. becculata (Mackay & Mackay, 2010), M. cernua (Mackay & Mackay, 2010), M. conicula (Mackay & Mackay, 2010), M. longidentata (Mackay & Mackay, 2010), and M. pergandei (Forel, 1909).