The Bivalve Mollusc Fauna of Ancient Lakes in the Context of the Historical Biogeography of the Balkan Region

Abstract

One of the most remarkable features of the Balkan freshwater environment is the presence of so called ancient or long-lived lakes, Ohrid and Prespa being the most famous among them. Existing continuously for several millions of years, such lakes are distinguished by their rich and unique faunas (Stankovic, 1960; Starobogatov, 1970; Taylor, 1988; Wesselingh & Michel, 2001), and undoubtedly constitute “hot spots” of biodiversity. Investigations of these peculiar habitats, and, in particular, their rich mollusc fauna, are important for biogeographical regionalisation, reconstructing the history of the fauna and understanding the mechanisms of speciation (Starobogatov, 1970; Taylor, 1988; Wesselingh & Michel, 2001). To date, such investigations have focused on the extremely diverse gastropod faunas of Tanganyika and Baikal, and the ancient lakes of Sulawesi, where endemism may reach generic or even family level. Modern methods of cladistic phylogenetic analysis on phenetic and molecular data have been applied to clarify within- and between-group relationships of endemic taxa (Glaubrecht, 2001; Sitnikova, 2001; Todd & Michel, 2001; West & Michel, 2001). In contrast, the molluscs of Balkan lakes have been reviewed in several classical works (Stankovic, 1960; Maassen, 1980; Radoman, 1983, 1985; Meier-Brook, 1983; Dhora & Welter-Schultes, 1996) but have not yet been the subject of up-to-date multidisciplinary research.