Phylogenetic analysis of the genus Paratanytarsus (Diptera: Chironomidae)

Abstract

The non-biting midges (Chironomidae) are among of the most successful insects in freshwater systems and often dominate in abundance and species richness. The genus Paratanytarsus contains species from all biogeographic regions except tropical Africa, 19 species are known from Europe. Previous molecular work has suggested the presence of undescribed species within some species groups, in addition the monophyly of the genus has been questioned. In this study four nuclear molecular markers, CAD1, CAD4, PGD and AATS1 are utilized in order to reconstruct the evolutionary history of the genus. Samples identified to 16 different species have been collected at locations in Northern Europe, Arctic Canada and Australia. The results of the phylogenetic analysis supports the monophyly of the genus, while considerable intraspesific variation is revealed within several species. Material identified to P. austriacus/hyperboreus is found to group into four separated genetic clusters, two of which appear to be undescribed cryptic species based on currently used morphological characters. Canadian P. dissimilis and P. tenuis ends up paraphyletic with respect to European samples and might represent new Nearctic species. The Australian taxa came out well-embedded in the tree without any close relatives. It is hypothesized that bipolar migrations has occurred in the history of the genus.