Leucosia anatum, also known as the pebble crab, is a species of crab in the family Leucosiidae.
This species has a strongly convex, elongate carapace. Its outline is somewhat rhomboidal. The front edge of the carapace is slender and obtusely triangular, with a pointed postorbital that points upward at an oblique angle. It has stout ambulatory legs, with each section being cylindrical and fairly smooth.
This species is known to occur in the following locations: