Repeated convergent evolution of parthenogenesis in Acariformes (Acari).

The existence of old species-rich parthenogenetic taxa is a conundrum in evolutionary biology. Such taxa point to ancient parthenogenetic radiations resulting in morphologically distinct species. Ancient parthenogenetic taxa have been proposed to exist in bdelloid rotifers, darwinulid ostracods, and in several taxa of acariform mites (Acariformes, Acari), especially in oribatid mites (Oribatida, Acari).

Convergent evolution of aquatic life by sexual and parthenogenetic oribatid mites.

Convergent evolution is one of the main drivers of traits and phenotypes in animals and plants. Here, we investigated the minimum number of independent colonisations of marine and freshwater habitats in derived oribatid mites (Brachypylina), a mainly terrestrial taxon. Furthermore, we investigated whether the reproductive mode (sexual vs.

Convergent evolution of defense mechanisms in oribatid mites (Acari, Oribatida) shows no "ghosts of predation past".

Oribatid mites are diverse and abundant terrestrial soil arthropods that are involved in decomposition of organic matter and nutrient cycling. As indicated by fossils starting from the Devonian, they evolved varied mechanisms and structures for defense from predators. We investigated four of these defensive structures (ptychoid body, hologastry, mineralization and opisthonotal glands) and used ancestral character state reconstruction to determine whether they evolved convergently and how many times this may have happened.