Sampling locations (red squares) of minnows in the Po catchment in the Italian Piedmont (green box) where specimens of P. lumaireul were caught and used for the nuptial colouration characterisation (see Tab. 1, Figs. 2, 4b, and 5c), as well as in the French part of the Lake Geneva (red box) where the minnow specimen of unknown species was photographed and presented in Fig. 4a. Locations: 1) Varaita Torrent at Costigliole Saluzzo 44°33’49’’N – 7°28’29’’E, 2) Chisone Torrent at Pinerolo 45°51’42’’N – 7°20’41’’E, 3) Lago Laus, Roreto Chisone 45°03’00’’N – 7°08’08’’E, 4) Sangone Torrent at Trana 45°01’43’’N – 7°23’42’’E, 5) Lake Geneva at Publier 46°23’46”N – 6°32’22”E.