Luidia senegalensis, the nine-armed sea star, is a tropical species of starfish in the family Luidiidae found in the western Atlantic Ocean.

The oral or underside of the sea star has further small white spiny plates down the edges of the arms and a central band of translucent, orange tube feet.

[3] The nine-armed sea star is a scavenger and a predator and examination of the stomach contents show that the diet consists primarily of molluscs, small crustaceans and polychaete worms.

[4] It also buries itself in the substrate and engulfs "mouthfuls" of sediment, filtering it through its oral spines and extracting detritus and small organisms such as brittle stars.

Zinc, and to a lesser extent nickel, lead, cadmium and silver accumulate in the body wall and the pyloric caeca (parts of the gut which project into the arms).