The Alps, with geographic boundaries of the taxa of E. euryale discussed in this paper. Light grey: mountain areas above 1000 m, dark grey: lakes. Solid lines: group boundaries. Dotted lines: subspecies boundaries. Circle – the adyte group, with ssp. adyte (1); squares – the euryale group with ssp. isarica (2) and ssp. ocellaris (3); diamonds – the kunzi group, with ssp. pseudoadyte (4) and ssp. kunzi (5). T = Trafoi test region, R = Passo Rolle test region, F = Falcade test region. The intergradation zone isarica / ocellaris is included in the ocellaris area.