Stelleroidea
Encyclopedia
Stelleroidea is a superclass of marine
invertebrate
s including three classes:
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s including three classes:
- Asteroidea: true sea starSea starStarfish or sea stars are echinoderms belonging to the class Asteroidea. The names "starfish" and "sea star" essentially refer to members of the class Asteroidea...
s - Ophiuroidea: brittle starBrittle starBrittle stars or ophiuroids are echinoderms in the class Ophiuroidea closely related to starfish. They crawl across the seafloor using their flexible arms for locomotion. The ophiuroids generally have five long slender, whip-like arms which may reach up to in length on the largest specimens...
s and basket starBasket starBasket stars are a group of brittle stars. They are treated as a suborder Euryalina or order Euryalida. Many of them have characteristic many-branched arms. They generally live in deep sea habitats.The life span in the wild is up to 35 years. They weigh around 11 lbs, or 5 kg...
s - Somasteroidea (sometimes also Stomasteroidea): ancestral stelleroids