Reverse evolution and cryptic diversity in putative sister families of the Oribatida (Acari)

The family Zetorchestidae is a morphologically and ecologically diverse group assigned to the higher oribatid mites (Brachypylina). We addressed the phylogeny of the family by including species of the genera Belorchestes, Litholestes, Microzetorchestes and Zetorchestes. We also analysed the affinities of the putative sister taxon (Eremaeidae), investigating Eremaeus and Eueremaeus. Zetorchestidae, Eremaeidae and Niphocepheidae were recently combined in one superfamily (Zetorchestoidea). These taxa were placed into a wider phylogenetic context by adding other presumably closely related taxa. Phylogenetic analyses based upon nuclear and mitochondrial DNA-sequences revealed the monophyly of the Zetorchestidae as well as of all investigated species and genera of this family. Ancestral state reconstruction of jumping ability in latter family, moreover, suggested reverse character evolution within the studied zetorchestid taxa. Genetic diversity of the genera Eremaeus and Eueremaeus turned out to be higher than known, suggesting the existence of cryptic species. However, none of our analyses supported a sister group relationship among Zetorchestidae and Eremaeidae. Moreover, all calculated trees show a paraphyletic position between Zetorchestidae respectively Eremaeidae and Niphocepheidae.