Description of Hypogeoppia belgicae, a new species of cave mite (Acari, Oribatida), and comments on some characters

The Oppiidae (Acari, Oribatida) are one of the largest families of Circumdehiscentiae. Within this family, the genus Hypogeoppia comprises few species, all soil organisms. Here we describe a new species, H. belgicae, from adult specimens collected in caves in South Belgium. Several characters showed a substantial variability in the two populations studied. In addition, H. belgicae displays some uncommon or unique apomorphic features such as a notogasteral posteromedian notch, prodorsal and podosomatic taenidia, elongated chelicerac, internal subcapitular septa, and tracheal vesicles III.