Population Genetics and Systematics of European Unionoidea

The taxonomy and systematics of European freshwater mussels (naiades: Unionidae and Margaritiferidae) have suffered from an overestimation of shell characters. Since ecological factors have a strong influence on shell form (Ortmann 1920; Agrell 1948; Kodolova and Logvinenko 1973; Watters 1994), the need to study other characters became obvious. Among others, Davis (1983, 1994) advocated comparing all available information from as many independent sources as possible to arrive at a stable and comprehensive scheme of phylogenetic relationships. Nagel (1988; see also Nagel et al. 1998) proposed a system of European naiades based on anatomical (gills, stomach), microstructural (shell) and morphological (larvae) characters (see Table 4.1). This formed the background for our study of population genetics.