The royal starfish (Astropecten articulatus) is a species of starfish found in the western Atlantic Ocean including the United States East Coast, the Gulf of Mexico, and the Caribbean Sea. It is one of the most common sea stars along the southeast coast of the United States. It is usually dark blue to purple with orange marginal plates. The royal is a carnivore and feeds on mollusks, which it catches with its arms. It then maneuvers its prey to its mouth cavity. Unlike other starfish, it swallows food whole.