Leptothyra arenacea Pritchard & Gatliff, 1902 Charisma arenacea, common name the sandy charisma, is a species of extremely small sea snail, a marine gastropod mollusk in the family Trochidae, the top snails.

The small, solid, umbilicate shell has a turbinate shape.

The nuclear whorls are smooth, the rest are spirally ridged.

These ridges are well-developed and number about 11 to 13 around the circular aperture on the body whorl.

The umbilicus is deep and extends at the back of the columella to the anterior of the aperture.