Rotaliotina discoidea , common name the discoid delphinula, is a species of small sea snail, a marine gastropod mollusk, in the family Liotiidae.

The shell has a discoidal shape, with a flattened spire.

The periphery shows two prominent ribs, connected by lattices which a subspinously project.

The surface contains clathrate ridges, the interstices of which are finely striated.

[2] This marine species occurs off the Philippines, Papua New Guinea and Australia (Queensland) and Norfolk Island and Lord Howe Island.