Phylogenetic placement of North American subterranean diving beetles (Insecta: Coleoptera: Dytiscidae).

A phylogenetic analysis of Hydroporinae (Coleoptera; Dytiscidae) is conducted with emphasis on placement of the North American subterranean diving beetles Psychopomporus felipi Jean, Telles & Miller, Ereboporus naturaconservatus Miller, Gibson & Alarie, and Haedeoporus texanus Young & Longley. Analyses include 49 species of Hydroporinae, representing each currently recognized tribe except Carabhydrini Watts. Data include 21 characters from adult morphology and sequences from seven genes, 12S rRNA, 16S rRNA, cytochrome c oxidase I, cytrochrome c oxidase II, histone III, elongation factor I alpha, and wingless. The combined data were analyzed using parsimony and mixed-model Bayesian tree estimation, and the combined molecular data were analyzed using maximum likelihood. Less inclusive branches (genera, genus-groups, and tribes) are well-supported under each criterion, but relationships among tribes are not. These branches are short, poorly supported and in conflict among the estimation methods. Because of certain anomalous relationships in the parsimony and likelihood results, and greater consistency of the Bayesian results with morphological data, this is our preferred phylogenetic estimate. Haedeoporus Young & Longley is related to Neoporus Guignot, Heterosternuta Guignot, and other members of the Hydroporus-group of genera of Hydroporini sensu lab. Psychopomporus Jean, Telles & Miller and Ereboporus Miller, Gibson & Alarie are nested within the Graptodytes-group of genera of Hydroporini sensu lato, and are the only North American members of this otherwise Mediterranean group. Congruent results between optimality criteria indicate that Hydroporini sensu lato is conspicuously non-monophyletic