Phylogenomics of the major lineages of Bembidion and related ground beetles (Coleoptera: Carabidae: Bembidiini)

Bembidion Latreille (Coleoptera: Carabidae) is a genus of small ground beetles containing about 1,380 species. To test previous phylogenetic hypotheses about deeper lineages of Bembidion and near relatives, we recover and examine over 1,800 nuclear protein-coding loci from 33 species representing the main lineages of Bembidion, 10 species of other bembidiine genera, and 7 outgroups. We find that Bembidion exclusive of subgenus Phyla Motschulsky is monophyletic, and we reclassify Phyla as a separate genus. Within Bembidion we find 2 dominant clades, the Bembidion superseries (containing about 490 species in the subgenera Eupetedromus Netolitzky and Lindrochthus Maddison, the Philochthus Stephens complex, and the Bembidion series), and the Ocydromus Clairville superseries (containing almost all other Bembidion representing about 840 species). The only known lineages within Bembidion outside of these superseries are subgenus Hoquedela M & uuml;ller-Motzfeld and the Desarmatocillenus Netolitzky complex, which combined contain less than 30 species. Most clades are insensitive to variations in analyses and hold up under different sets of taxa and loci, analyses at the nucleotide or amino acid levels, and different analytical methods (maximum likelihood, including posterior mean site frequency analyses, Bayesian analyses, invariant-based methods, and those that consider incomplete lineage sorting). Despite the clarity achieved in most aspects of the phylogeny, there are several unresolved regions, notably the relationships of Desarmatocillenus, Hoquedela, and Phyla to other bembidiines. A divergence dating analysis suggests that crown Bembidion is about 48 million years old (95% confidence intervals 40-58 Ma), and that the 2 large superseries are about 38 million years old (95% confidence intervals about 29-47 Ma).