The molecular diversity of adriatic spined loaches (Teleostei, Cobitidae)

Abstract

The sharp contrast in diversity observed between Central and Southern European freshwater biotas in the Euro-Mediterranean peninsulas (Iberian, Italian, and Balkans) has attracted the interest of many biologists (Banarescu, 1992; Hewitt, 2000). These faunal differences are especially noticeable in the primary freshwater fishes that exclusively dispersed across continental routes (Myers, 1949). The generally impoverished nature of species-level taxa in Central European waters (see, however, Kottelat and Persat, 2005) appears to be related to the smooth topography of Central Europe, which favored river captures and contact among fishes. In contrast, the ancient separation of Euro-Mediterranean peninsulas by old mountain systems promoted the endemicity of their freshwater fish fauna. Today’s Adriatic region encompasses Italy and the western Balkans as a well-defined geographical area of southern Europe enclosed by the Alps, the Apennines and the Dinaric and Balkan Mountains (Fig. 1). This area is drained by relatively old, short river systems and contains the oldest European Lakes, lakes Ohrid and Skadar. The Adriatic area spanned the Paratethys border from the Middle Miocene (15 MYA) and is a geologically active region. The geological record suggests the presence of a well-established terrestrial zone in the Western Balkans from the Middle Miocene to the present (Hsu et al., 1977; Steininger and Rogl, 1984). The final emergence of the Alps in the early Middle Miocene (approximately 16.5 MYA) promoted the northern and final closure of the Paratethys–Mediterranean paleobasins, while uplift of the Dinaric Mountains (approximately 12 MYA) led to the Danube–Mediterranean separation.