Freshwater snails of the genera Fluvidona and Austropyrgus (Gastropoda, Hydrobiidae) from northern New South Wales and southern Queensland, Australia

The freshwater snail genus Fluvidona (Gastropoda, Caenogastropoda, Rissooid ea, Hydrobiidae) is reapprasied and described using anatomical, shell, radu la and opercular characters. Five species, three of them new, are described , being differentiated using anatomical, shell and opercular character stat es. A sixth species, similar to the Fluvidona species, is described and is tentatively assigned to the genus Austropyrgus Cotton. All six species live in northern New South Wales and southern Queensland and all are from singl e localities or very restricted areas. All species live in small streams, a lthough one was found aestivating in soil in the bed of a small dry creek. The new species placed in Austropyrgus, from the Bunya Mountains, Queenslan d, is widely separated from putative congeners that are found in southern N ew South Wales and other parts of south-eastern Australia.