Integrative taxonomy and species delimitation of water mites: the case of the Lebertia porosa (Acari, Parasitengona, Hydrachnidia) species complex

Water mites form a highly diverse taxon of Acari unified by adaptations to aquatic life. Despite a high number of already described species, more than half as many remain unknown to science. Their ecology makes them good candidates for use as bioindicators, but the high number of undescribed species impedes this potential. Lebertia porosa is a water mite species described in 1900 from southern Norway. DNA barcode data sorted the specimens morphologically identified as L. porosa (s.l.) into ten genetic clusters (BINs), indicating the presence of a species complex. In this project, I investigated the species boundaries within the L. porosa complex by applying integrative taxonomy. DNA was extracted from 46 specimen collected across Norway, including the type locality. The COI mitochondrial DNA marker and 18S and 28S ribosomal nuclear DNA markers were sequenced, edited, and delimited using multiple methods (GMYC, ASAP, ABGD, PTP, and BPP). The samples were also checked for the presence of the bacterium Wolbachia – a known manipulator of arthropod lineages. Slide-mounted specimens were studied and measured to detect morphological differences. The results indicate the presence of seven genetically and morphologically distinguishable clades. A single Wolbachia strain was detected among specimens from two clades, indicating no deducible pattern of interference from the bacteria. Three clades were identified from the type locality. One of these was assigned the nominal species Lebertia porosa based on the original species description