Litiopa melanostoma, common name the brown Sargassum shell, is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Litiopidae.

[1] This species occurs in the Gulf of Mexico, the Caribbean Sea, the Lesser Antilles, Puerto Rico and off the Azores; in the North Atlantic Ocean, off Newfoundland.

Litiopa melanostoma (Sargassum Snail) has been found to have a maximum recorded shell length of 6 mm.

[2] The minimum recorded depth for this species is 0 m; the maximum recorded depth is 805 m.[2] The snail is known to live on floating beds of Sargassum.

This Litiopidae-related article is a stub.