The correlation between the size of Lower and Middle Pleistocene Cyprideis torosa Cores) ostracode valves and paleosalinity reveal the existence of a direct relationship though little significant. This observation suggest that in spite of the two areas of Cullar-Baza Basin, where the ostracodes have been picked, were controlled under similar general paleodimatic conditions, the particular and local paleogeographical conditions had a major influence not only in the specific diversity but also in the morphology of the ostracodes