Potamolithus is a genus of small freshwater snails that have an operculum, aquatic gastropod mollusks in the family Tateidae.

[2] However, anatomical study of Potamolithus by Davis & Pons da Silva (1984)[2] showed its relationship with Lithoglyphus,[2] and it is then placed within the family Lithoglyphidae.

The first appearance of the name Potamolithus was in November 1896 as a nomen nudum (a bare name with no description or illustration).

[1] Potamolithus is the only genus of the family Tateidae in South America.

[3] Potamolithus is the largest genus (i.e. the one with the highest species richness) of recent freshwater snails in Argentina[7] and in Uruguay.