Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea. Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. Starfish are also known as asteroids due to being in the class Asteroidea. About 1,900 species of starfish live on the seabed in all the world's oceans, from warm, tropical zones to frigid, polar regions. They are found from the intertidal zone down to abyssal depths, at 6,000 m (20,000 ft) below the surface.
The Asterinidae are a large family of sea stars in the order Valvatida.
Goniasteridae constitute the largest family of sea stars, included in the order Valvatida. They are mostly deep-dwelling species, but the family also include several colorful shallow tropical species.
The Forcipulatida are an order of sea stars, containing three families and 49 genera.
The Brisingids are deep-sea-dwelling starfish in the order Brisingida.
Psilaster andromeda is a species of starfish in the family Astropectinidae. It is native to the northeastern Atlantic Ocean where it occurs at abyssal depths.
Leptasterias is a genus of starfish in the family Asteriidae. Members of this genus are characterised by having six arms although five-armed specimens sometimes occur. L. muelleri is the type species. The taxonomy of the genus is confusing and Leptasterias hexactis seems to be a species complex. Some species brood their eggs.
Hippasteria is one of 70 genera of sea stars in the diverse family Goniasteridae.
Xyloplax medusiformis is a sea daisy, a member of an unusual group of marine taxa belonging to the phylum Echinodermata. It is found at bathyal depths in waters around New Zealand. It was first described in 1986 by Baker, Rowe and Clark and is the type taxon of the genus Xyloplax. Its generic name derives from the Greek "xylo" meaning wood and its specific name was chosen because its morphology superficially resembles that of a cnidarian medusa.
Poraniidae is a family of starfishes in the order Valvatida.
Poraniopsis inflata, the spiny sea star, is a species of starfish in the family Poraniidae. It is native to the Pacific Ocean and is found in deep water off the coast of North America.
Bathyporania ascendens is a species of starfish in the family Poraniidae, and the only species of the genus Bathyporania. It is native to the Pacific Ocean and is found in deep water off the coast of North America.
Evoplosoma is a genus of deep-sea sea star in the family Goniasteridae.
Apollonaster is a genus of abyssal sea stars in the family Goniasteridae. They can be identified by their bare abactinal plate surfaces and multiple accessory granule rows on their abactinal plates. To date, Apollonaster has been found in the tropical Atlantic region and Hawaiian Islands region oceans, with no other locations or species being known as of 2015.
Hippasteria muscipula is one of twelve species of deep-sea sea star in the genus Hippasteria, which is in the family Goniasteridae.
Evoplosoma claguei is a species of deep sea corallivores. This species in particular is found in seamounts in the North Pacific.
Evoplosoma voratus is a species of deep sea corallivores. This species in particular is found in seamounts in the North Pacific.
Meyenaster is a genus of starfish in the family Asteriidae. It is a monotypic genus and the only species is Meyenaster gelatinosus which was first described by the Prussian botanist and zoologist Franz Julius Ferdinand Meyen in 1834. It is found in the southeastern Pacific Ocean on the coasts of South America.
Anasterias antarctica, commonly called the Cinderella starfish, is a species of starfish in the family Asteriidae. It is found in coastal waters in the Southern Ocean and around Antarctica.
Cryptasterina is a genus of starfish belonging to the family Asterinidae. They occur in the Indian and Western Pacific Oceans in the littoral and shallow sublittoral zone.
