Brief insight in the paleogeographic evolution of the Mediterranean Sea, the Black Sea, the Sea of Azov, the Caspian Sea, and the Aral Sea basins is presented. All of them are remains of the Tethys Sea, a prehistoric ocean, existed during much of the Mesozoic Era and early-mid Cenozoic Era, which was the predecessor to the modern Indian Ocean, the Mediterranean Sea, and the Eurasian inland marine basins. The geological history of tectonic processes and the associated repeated disconnections and mergers of basins in various geological epochs has been traced back to the present state. Geologically speaking, hyperkinetic development process ended when the present-day biota of the basins were formed. During the Late Quaternary, each of the southern basins was subject to its own evolutionary history. Regardless of differences in physical-geographic factors, hydrological regimes, and resident fauna, all modern Ponto-Caspian seas have significant common features: salinity different from standard ocean value (either exceeding normal oceanic salinity like the Mediterranean Sea, or below it like the Black Sea, Sea of Azov, Caspian and Aral Seas) and isolation from the world ocean.