Molecular phylogeny, evolution and classification of the H ydrophilidae ( C oleoptera)

Abstract The phylogeny and evolutionary history of the water scavenger beetles ( C oleoptera: H ydrophilidae) are inferred from comprehensive analyses of DNA sequence data from the mitochondrial genes COI , COII and 16S and the nuclear genes 18S , 28S and arginine kinase . Bayesian and maximum parsimony analyses included 151 taxa, representing all subfamilies, tribes and subtribes that have ever been proposed in the family, as well as representatives of the hydrophiloid families H elophoridae, H ydrochidae, S percheidae, E pimetopidae and G eorissidae. The resulting well‐supported trees strongly disagree with prior classifications of the H ydrophilidae, suggesting that the smaller subfamilies ( H orelophinae, H orelophopsinae and S phaeridiinae) are derived from within the larger H ydrophilinae. The existing tribal classification is more compatible with our results, but many significant differences are evident. Here, we present a new classification of the H ydrophilidae comprising 6 subfamilies and 12 tribes. Each subfamily and tribe is reviewed in detail with (i) a morphological diagnosis, including known or putative morphological synapomorphies, (ii) its taxonomic circumscription, including genera not included in our analyses, and (iii) a review of its general biology and geographic distribution. A new identification key to subfamily and tribe based on adult morphology is also provided. The newly adopted classification requires the following taxonomic changes: the subfamily H ydrophilinae sensu n. is redefined to include only the tribes A mphiopini stat.n. (removed from the synonymy with the C haetarthriini), B erosini, L accobiini, H ydrophilini and H ydrobiusini (= S perchopsini syn.n. ); the subfamily C haetarthriinae stat.n. is removed from synonymy with the H ydrophilinae and includes the tribes C haetarthriini and A nacaenini (= H orelophinae syn.n. ); the A cidocerinae stat.n. (= H orelophopsinae syn.n. ) and R ygmodinae stat.n. (= Andotypini syn.n. , B orborophorini syn.n. and T ormissini syn.n.) are elevated to subfamily rank; and the subfamily E nochrinae subfam.n. is established for the genus Enochrus and its relatives. The implications for the morphological evolution, ecological transitions and biogeography of the family are discussed.