The Sharr Mountains are one of the most important hotspots of terrestrial and freshwater biodiversity in the Balkan Peninsula, with many endemic and rare species. The caddisfly studies in this area increased during the past years, although insufficiently investigated areas still remain.
In this paper, we describe a new species, Potamophylax humoinsapiens sp. n. from the Sharr Mountains in the Republic of Kosovo, which is morphologically closest to Potamophylax idliri Ibrahimi, Bilalli & Kučinić, 2022 and Potamophylax juliani Kumanski, 1999. The males of the new species differ from all known species of the Potamophylax winneguthi Species Group by their uniquely-shaped parameres, which are long, bulbous in their basal half and thin in the remaining length, with a bunch of very thin and long, hair-like spines, grouped uniformly at the apex. The new species further differs from its most similar congeners by its very wide distance between the dorsal and ventral edges of the apical part of inferior appendages in lateral view. The new species was found at three localities from 1416 to 1505 m a.s.l.
Similar to the other species of the Potamophylax winneguthi Species Group, which have very narrow distribution areas, we posit that Potamophylax humoinsapiens sp. n. is a microendemic of the Sharr Mountains. The new species is the second known caddisfly species occurring only in the Kosovan part of the Sharr Mountains.