Rivomarginella Brandt, 1968, is the only genus of the Marginellidae living in freshwater. The type species, R. morrisoni Brandt, is known from rivers and lakes in Thailand. Marginella electrum Reeve, 1865, is assigned to the genus Rivomarginella. Specimens of R. electrum (Reeve) are mentioned from freshwater localities in Sumatra and Borneo, Indonesia. Sumatra is selected as the type locality.