High Quality Content by WIKIPEDIA articles! Sea stars are echinoderms belonging to the class Asteroidea. The names "sea star" and "starfish" essentially refer to members of the Class Asteroidea. However, common usage frequently finds "sea star" and "starfish" also applied to ophiuroids which are correctly referred to as "brittle stars or "basket stars". There are over 1800 species of living species of sea stars that occur in all the world's oceans, including the Atlantic, Pacific, Indian as well as in the Arctic and the Southern Ocean (i.e., Antarctic) regions. Sea stars occur across a broad depth range from the intertidal to abyssal depths (6000 m).