Insights on the Existence of Ancient Glacial Refugee in the Northern Black/Azov Sea Lowland, with the Description of the First Stygobiotic Microcrustacean Species of the Genus Niphargus Schiödte, 1849 from the Mouth of the Don River

A new species of the genus Niphargus Schiödte, 1849 (Crustacea: Amphipoda: Niphargidae), co-existing with other stygobiotic amphipods, Diasynurella kiwi Marin and Palatov, 2023 Pontonyx donensis (Martynov, 1919) (Crangonyctidae), is described from a small spring on shore Kiziterinka River in Rostov-on-Don City mouth Don River. Two three studied spring, D. discovered Niphargus, belong to microcrustaceans not exceeding total body size 3 mm. The species, rostovi sp. nov., represents one smallest within mostly related Greek karkabounasi Ntakis, Anastasiadou, Zakšek Fišer, 2015, which also reaching One more undescribed found Crete Island by molecular genetic data. These represent separate phylogenetic lineage “carpathicus” complex, diverged congeners Late Miocene for than 10 Mya. At same time, speciation ingroup started about 5–6 Mya, obviously correlating drainage Euxinian basin Eastern Paratethys, connecting lower southern Greece areas. potamophilus Birštein, 1954 first recorded Belbek Crimean Peninsula, closing known area Kuban delta further along western coast Black Sea Bulgaria. Analysis recent records long-time lineages endemic/subterranean/stygobiotic animals unable disperse long distances assumed that glacial refugium existed at River, South Caucasus (Colchis) Caspian (Hyrcania), where many have survived several periods glaciation since late Miocene.