The ground beetles in the trees: Phylogeny and evolutionary diversification of the lebiomorph harpalines

The ground beetles (Carabidae) are a hyper-diverse lineage with around 40,000 species. However, the diversity of these beetles is disproportionately distributed taxonomically. The subfamily Harpalinae accounts for at least two-thirds of all species, but their success as a diverse lineage remains unexplained. Using 250 newly sequenced mitochondrial genomes from lineages across the major biogeographic realms we investigate the tribal relationships to recalibrate the current taxonomic hypotheses. The new tree places the great majority of species into two large sister clades, broadly corresponding the tribe Lebiini versus all other tribes of Harpalinae, each with a set of (sub)tribes that were mostly recovered as monophyletic. Immediate sister to this large clade were species in the tribes Brachinini, Dryptini and others, which exhibit truncated elytra as also seen in Lebiini, but these “Truncatipennes” thus were not monophyletic. Sequences from >5000 species of Carabidae were mined from public sites and added to the mitogenome tree, for an increasingly complete phylogeny of the family and better estimates of the biogeography and evolutionary studies of key traits, including arboreality and complex chemical defence mechanisms.