Gundlachia lucasi is a species of small freshwater snail or limpet, an aquatic pulmonate gastropod mollusk or micromollusk in the family Planorbidae.

Shell obliquely conical, thin, semitransparent, horn-colour, covered by a blackish coating.

[4] These animals have a pallial lung, as do all pulmonate snails, but they also have a false gill or "pseudobranch".

This serves as a gill as, in their non-tidal habitat, these limpets never reach the surface for air.

[4] These tiny limpets are found attached to stems and undersides of leaves of aquatic plants in quiet waters.