Since its first description from Madagaskar, there are about 16 living (Recent) species of the genus Zonocypris reported from Afrotropical, Neotropical and Palearctic regions. Similarly, there are about 16 fossil with two (sub)species of the genus known from the Early Cretaceous (e.g., India, France, Russia, China, Brazil) to Holocene (e.g., Albania). Among the species, the only species known with fossil and living species is Zonocypris costata. In Turkey, Zonocypris membranae with two subspecies (Z. m. membranae,Z. m. quadricella) is the only fossil species known while living individuals of Z. costata were encountered the southeast Anatolia. Additionally, Zonocypris mardinensis n. sp. is now proposed as a new species which shows clear differences in the soft body parts (e.g., aesthetasc ya in A1, knife-type G2 claw, shapes of clasping organs and hemipenis) and carapace structure (e.g., LV with extension, RV with posterior denticles). Overall, living species reported herein seem to inhabit comparatively warm (15-30 degrees C) within the ranges of slightly acidic to alkaline (pH 6.81-8.44) and low to well oxygenated waters (3.05-18.8 mg/l) where they can tolerate salinity (electrical conductivity 103-1910 mu S/cm) values within a limited elevational range (336-991 m). Our results suggest that geographic distribution of the living species of the genus is limited within southern parts of Turkey while fossil forms seem to exhibit much wider distribution in northern parts. Anatolian Diagonal as physical barrier may be considered to play a critical role on separating fossil (east-north regions) and extant (southeast region) species of the genus in Turkey. This is the first supportive evidence provided by the species of the genus Zonocypris that geographic barrier could have played the main role on its distribution.