A new species of the Drusinae subfamily, Drusus iani sp. nov., is described using an integrative approach that combines evidence from male and female morphology with molecular data. Morphologically, the new species is most similar to Drusus aranos Oláh 2017 (from Teberda, Russia), Drusus iranicus Oláh & Chvojka 2017 (from Central Elburz, Iran), Drusus polur Oláh 2017 (from Polour, Iran), and Drusus simplex Martynov 1927 (from Verchnij Sadon, Russia). The new species can be diagnosed from its congeners by a unique combination of morphological characters, primarily involving segment IX, the inferior appendages, and the parameres in males, as well as segment X, the vulvar scale, and the supragenital plate in females. To elucidate phylogenetic and taxonomic relationships and to corroborate the distinctiveness of the newly described species, Drusus iani sp. nov., we applied two phylogenetic inference methods and two species delimitation frameworks. Molecular analyses of various populations previously identified as Drusus simplex, collected from regions in Russia, Georgia, and Iran, indicate that this taxon represents a species complex rather than a single species. Drusus iani sp. nov., is currently known only from the Sabalan Mountains in Iran and represents the eighth documented species of the Drusus simplex Species Complex recorded in the country.
