Molecular phylogeny, systematics and biogeography of the subfamily Nemognathinae (Coleoptera, Meloidae)

Nemognathinae is the most widespread subfamily of Meloidae, with ~600 species, and includes the only blister beetles distributed in Australia and on islands of the western Pacific. Four tribes are recognised based on morphology: Stenoderini, Palaestrini, Horiini and Nemognathini. Using two mitochondrial (16S, COI) and three nuclear markers (CAD, 28S, ITS2), and both maximum likelihood and Bayesian approaches, this study describes the evolutionary history of Nemognathinae based on molecular data for the first time. We provided a fossil-calibrated phylogeny that unravels the phylogenetic relationships among the tribes and among most of the genera, and a reconstruction of the biogeographic history using a parametric approach. Our results recognised the four tribes that were described previously based on morphology and revealed the presence of another well-differentiated clade corresponding to the genus Zoltanzonitis. Phylogenetic relationships among the tribes are well supported, with Stenoderini as the most ancient lineage, followed by Zoltanzonitini, Palaestrini, Horiini and Nemognathini. A few long-standing genera within Nemognathini (Nemognatha, Zonitis, Stenoria) and the nominate subgenus Stenodera (Stenodera) were recovered as polyphyletic. In addition, biogeographic analyses revealed the origin of the subfamily in the Old World during the Eocene, and the associated diversification into the five tribes astride the Eocene and Oligocene between 46 and 30 Ma. Based on these results we propose the new tribe Zoltanzonitini, and the elevation of the subgenus Pronemognatha to genus level, new status. In addition, Zonitoschema breveapicalis new comb., Z. curticeps new comb. and Z. pulchella new status are proposed.