Wormaldia dilijanica sp. nov., a new caddisfly species (Trichoptera, Philopotamidae) from the Dilijan National Park in Armenia

The caddisfly fauna of Armenia is poorly known, and the country has been largely absent from recent faunistic and taxonomic research in the Caucasus region. In May 2025, a short field survey in the Dilijan National Park, northeastern Armenia, resulted in the discovery of a new species of Wormaldia McLachlan, 1865 from a tributary of the Aghstev River. Wormaldia dilijanica sp. nov. is described and illustrated based on male genital morphology. The species is distinguished by the combination of the following characters: slender, digitate apex of segment X; S-shaped, tapering superior appendages; second segment of inferior appendages nearly parallel-sided and as long as the first; broad anteromesal projection of segment IX; and a phallic organ bearing one large spine, one smaller spine, and a cluster of short basal spines. The new species is compared with Wormaldia kera Oláh, 2019 from Georgia and W. hoska Oláh, 2020 from Azerbaijan. Finding of the new species from Dilijan National Park in Armenia despite a very limited sampling efforts, suggests that the country harbors a rich but still undocumented fauna of caddisflies.