Theodoxus transversalis (Pfeiffer, 1828)
Distribution:
Apparently sympatric with Theodoxus danubialis (C. Pfeiffer, 1828). From the headwaters of the Danube River in Germany, through most of the river and tributaries in Austria, the Czech Republic, Slovakia, Hungary, Yugoslavia, and Bulgaria to the Black Sea. Also reported from Crete.
Habitat:
Freshwater: from mountain rivers and lakes to lowland deltas.