Phylogenetic analysis of Anacaenini (Coleoptera: Hydrophilidae: Hydrophilinae) based on morphological characters of adults

The skeletal features of adults of fifty species of Anacaenini (Coleoptera: Hydrophilidae) and six outgroup taxa belonging to Hydrophilini and Laccobiini were examined. Eighty-one characters were selected and analysed cladistically. The resulting trees confirm the sister group relationship of Anacaenini and Laccobiini. Paracymus forms a clade within Laccobiini, as sister group of Oocyclus. Paranacaena is highly polyphyletic and, like Hebauerina, Grodum and Enigmata deeply nested within a complex formed mainly by Anacaena species (Anacaena complex). The position of Gentilina remains ambiguous, but is also likely to be nested within this group. Notionotus is also part of this clade and clearly is monophyletic. Phelea, Crenitis and Notohydrus are distinctive groups which split off successively at the base of the Anacaena complex. On the basis of our results Enigmata Hansen (syn.n.), Gentilina Hebauer (syn.n.), Grodum Hansen (syn.n.) and Hebauerina Gentili (syn.n.) are synonymized with Anacaena Thomson.