New Data on the Distribution of Gastropod Theodoxus Pallasi Lindholm, 1924 (Mollusca, Gastropoda) in the Kuibyshev Reservoir, Russia

The gastropod Theodoxus pallasi Lindholm, 1924, which is a representative of the Ponto-Caspian fauna complex, has been recorded for the first time in the Volga reach of the Kuibyshev reservoir. Previously, it was indicated only for the Near-dam reach of the reservoir. The data indicate the continuing process of settling by the invader mollusk up the Volga River.