Phylogenetic relationships of Australian Scirtidae (Coleoptera) based on mitochondrial and nuclear sequences

Abstract

Scirtidae is a cosmopolitan group of beetles with aquatic or saproxylic larvae. A large diversity of species has recently been described from Australia, but their systematics is uncertain. There is evidence that current genera are polyphyletic and that Australian species were wrongly placed in northern hemisphere genera. Here we investigate the systematics of Australian Scirtidae using molecular phylogenetic analyses of combined data from the mitochondrial cytochrome c oxidase subunit 1 (COI) and nuclear gene elongation factor 1-α (EF1-α) genes. We also assess the current taxonomy of Australian Scirtidae using partial COI sequences. Bayesian phylogenetic analyses of COI and EF1-α sequence data from 81 taxa show that the Australian genera Contacyphon, Pseudomicrocara and Prionocyphon are polyphyletic. There is no close relationship between Australian and Eurasian genera, with the exception of Scirtes. Phylogenetic analyses of partial COI data from Australian Scirtidae generally support the current α taxonomy, with the exception of several species that may be associated with species complexes. Geographically a high proportion of species lineages are restricted to relict patches of wet forest suggesting that they may be relict populations. The phylogeny and sequence data presented here provide a sound basis for further systematic and biogeographical studies of the Scirtidae.