Ergalatax margariticola, common name : the shouldered castor bean, is a species of sea snail, a marine gastropod mollusk in the family Muricidae, the murex snails or rock snails.
The shell size varies between 14 mm and 40 mm
This species is distributed in the Red Sea, the Indian Ocean along Aldabra, Chagos, Madagascar, the Mascarene Basin, the Seychelles, Tanzania, and in the Western Pacific Ocean and Japan.