At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan

The species diversity of glossiphoniid leeches of the Ferghana Valley was studied. Both morphological features and molecular data were employed to identify the leeches and to trace their evolutionary history. The mitochondrial gene cytochrome c oxidase subunit I (COI) was used as a molecular marker. The Palearctic leeches Alboglossiphonia hyalina (Müller, 1774) and Helobdella stagnalis (Linnaeus, 1758) are recorded for the Ferghana Valley based on their morphology and molecular characters. The endemic Glossiphonia ferghanensis Solijonov, Izzatullaev & Kuchboev, 2022 differs from typical representatives of the related G. concolor (Apáthy, 1888) in the dorsal colouration and forms a well-separated clade confirming the species status of the Ferghana population. Alboglossiphonia weberi (Blanchard, 1897) is the first molecularly and morphologically substantiated record of an Oriental leech species in the Ferghana Valley, Uzbekistan and Central Asia.