Whole Genome Shotgun Phylogenomics Resolve the Diving Beetle Tree of Life
Diving beetles (Dytiscidae) are important generalist predators in freshwater ecosystems that have been around since the Jurassic. Previous studies have identified a largely stable set of monophyletic named groups (subfamilies, tribes and subtribes), however backbone relationships among these have remained elusive. Here we use whole-genome sequencing to reconstruct the phylogeny of Dytiscidae. We mine de novo assemblies and combine them with others available from transcriptome studies of Adephaga to compile a dataset of 154 taxa and 5440 orthologous genes. Species tree and concatenated maximum likelihood methods provide largely congruent results resolving all but two inter-subfamily nodes. All eleven subfamilies are monophyletic, possibly also all tribes but Dytiscini and Hydroporini are under at least one analysis setting recovered as paraphyletic supporting previous results. One large clade includes eight of eleven subfamilies (not including Laccophilinae, and Lancetinae + Coptotominae). Matinae is sister to Hydrodytinae + Hydroporinae in contrast with previous studies that have hypothesized Matinae as sister to the remaining Dytiscidae. Strongly confirmed sister-group relationships of subfamilies include Cybistrinae + Dytiscinae, Agabinae + Colymbetinae, Lancetinae + Coptotominae, and Hydrodytinae + Hydroporinae. Remaining problems include resolving the basal ingroup trichotomy, the position of Copelatinae, and relationships between tribes in Dytiscinae and Hydroporinae. A step forward towards completely resolving the backbone phylogeny of Dytiscidae, we hope this will stimulate further work on remaining challenges.