Unravelling the phylogeny, cryptic diversity and morphological evolution of Diptilomiopus mites (Acari: Eriophyoidea).

The Eriophyoidea, notable for specific morphological characters (four-legged mites) and gall-formation in host plants (gall mites), is one of the most species-rich superfamilies of Acari. Monophyly of the superfamily Eriophyoidea is accepted by all acarologists; however, monophyly of most genera has not been evaluated in a molecular phylogenetic network. Furthermore, most eriophyoid mites, especially species in the genus Diptilomiopus, are morphologically similar, challenging their identification. Here we test the phylogeny and cryptic diversity of Diptilomiopus species using fragments of two mitochondrial (COI and 12S) and two nuclear (18S and 28S) genes. Our results revealed the monophyly of Diptilomiopus. Sequence distance, barcode gap, and species delimitation analyses of the COI gene allowed us to resolve cryptic diversity of Diptilomiopus species. Additionally, we supposed that characteristics of genu fused with femur on both legs and seta ft' absent on leg II evolved only once within Diptilomiopus, which are potential morphological synapomorphies. In contrast, characteristics of both setae ft' and ft″ divided into a short branch and a long branch were supposed evolving multiple times independently. Our findings contribute to the understanding of phylogeny and morphological evolution of Diptilomiopus species and provide a DNA-based approach for species delimitation of Diptilomiopus mites.