The ant genus Aphaenogaster Mayr is an ecologically diverse group that is common throughout much of North America. Aphaenogaster has a complicated taxonomic history due to variability of taxonomic characters. Novomessor Emery was previously synonymized with Aphaenogaster, which was justified by the partial mesonotal suture observed in A. ensifera Forel. Previous studies using Bayesian phylogenies with molecular data suggest Aphaenogaster is polyphyletic. Convergent evolution and retention of ancestral similarities are two major factors contributing to non-monophyly of Aphaenogaster. Based on 42 multi-state morphological characters and five genes, we found Novomessor more closely related to Veromessor Forel and that this clade is sister to Aphaenogaster. Our results confirm the validity of Novomessor stat. r. as a separate genus and it is resurrected based on the combination of new DNA, morphological, behavioral and ecological data. Twenty-three Aphaenogaster species (Hymenoptera: Formicidae) occur in North America. While morphology and ecology define most species, the species limits of a group in the Eastern United States are unclear. In particular, the morphological and behavioral characters once thought to define A. carolinensis, A. picea and A. rudis do not associate with their hypothesized species limits. These observations suggest that these species are not monophyletic. We therefore tested the monophyly of Aphaenogaster in the context of molecular phylogenetic analyses. We used DNA data from five genes: CO1, CAD, EF1αF2, Long-wavelength Rhodopsin and Wingless to reconstruct phylogenies for 44 Aphaenogaster and outgroup species. In the resulting trees, reconstructed using parsimony and Bayesian inference, species boundaries associate with well-supported monophyletic clades of individuals collected from multiple locations. For example, A. carolinensis was monophyletic and a missing CAD intron was a diagnostic trait for the clade. However, some clades were unresolved, and A. picea and A. rudis were not monophyletic. Given the short branch lengths, these results suggest that these ants have likely recently radiated, and lack of gene lineage sorting explains the non-monophyly of species. Conversely, these results may indicate that clades of multiple species represent fewer but morphologically varied species. Additional biological information concerning pre- and post-mating barriers is needed before a complete revision of species boundaries for Aphaenogaster.Aphaenogaster Mayr 1853, contains 227 species worldwide (Bolton 2006) with 23 valid North American species, several species of which are hard to separate based on morphology alone (Umphrey 1996). The difficulty in identifying some of these species is due to limited diagnostic characters and to the lack of a comprehensive illustrated key. A recent analysis returned three species from Aphaenogaster to Novomessor, thus making Aphaenogaster in North America monophyletic (DeMarco and Cognato 2015). While many species have easily identifiable morphological characters, some east coast species within the A. rudis clade in North America are difficult to differentiate. Two of these species, A. carolinensis and A. miamiana, can be diagnosed using DNA. The gene CAD was missing an intron in those taxa. Four additional taxa, all identified morphologically as A. rudis, were found to be polyphyletic (DeMarco and Cognato, in prep, or see Chapter 2).
Read
