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 Echinasteridae are a family of starfish in the monotypic order Spinulosida. The family includes eight genera and about 133 species found on the seabed in various habitats around the world.
The Asterinidae are a large family of sea stars in the order Valvatida.
Patiriella is a genus of sea stars of the family Asterinidae. Many species formerly included in this genus have been transferred to other genera. They are commonly known as carpet sea stars.
Meridiastra calcar, formerly classified as Patiriella calcar, is a species of sea star in the family Asterinidae. It is endemic to Australia. It is commonly known as carpet sea star, cushion sea star, or eight-armed sea star.
Leptasterias hexactis is a species of starfish in the family Asteriidae, commonly known as the six-rayed star. It is found in the intertidal zone of the western seaboard of the United States. It is a predator and is unusual among starfish in that it broods its eggs and young.
Acanthaster brevispinus, the short-spined crown-of-thorns starfish, is one of the two members of the starfish genus Acanthaster, along with the much better-known A. planci, the common crown-of-thorns starfish.
Anasterias rupicola is a species of starfish in the family Asteriidae. It is found in shallow waters in the Southern Ocean and sub-Antarctic Indian Ocean.
Labidiaster annulatus, the Antarctic sun starfish or wolftrap starfish is a species of starfish in the family Heliasteridae. It is found in the cold waters around Antarctica and has a large number of slender, flexible rays.
Callopatiria is a genus of starfish of the family Asterinidae. The genus is found in shallow waters off South Africa, down to a depth of about 82 m (269 ft).
Ophidiaster granifer, the grained seastar, is a species of starfish in the family Ophidiasteridae. It is found in the Red Sea and the Indo-Pacific and is the only known species of starfish to reproduce by parthenogenesis.
Parvulastra parvivipara is a very small species of starfish in the family Asterinidae. It is a viviparous species and gives birth to live young. It lives in rock pools on intertidal granite rocks in a limited area of South Australia.
Cryptasterina hystera is a species of starfish. It is found in a limited region of the coast of Australia and is very similar in appearance to Cryptasterina pentagona. The two appear to have diverged from a common ancestral line a few thousand years ago.
Asterina gibbosa, commonly known as the starlet cushion star, is a species of starfish in the family Asterinidae. It is native to the northeastern Atlantic Ocean and the Mediterranean Sea.
Nepanthia is a genus of starfish of the family Asterinidae. Members of the genus have four to seven rays and are found in the eastern Pacific Ocean, ranging from Burma and Indonesia to Australia.
Paranepanthia is a genus of starfish of the family Asterinidae. Members of the genus have five rays and are found in the waters around Australia, Indonesia and Antarctic New Zealand.
Neoferdina cumingi, also known as Cuming's sea star, is a species of starfish in the family Goniasteridae. It is native to the tropical Indo-Pacific region.
Parvulastra is a genus of starfish belonging to the family Asterinidae. The species of this genus are found in Southern Hemisphere.
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.
Meridiastra is a genus of star fish in the family Asterinidae. The genus is found in the Indian and Pacific Oceans, with most records from the waters around Australia. They occur in shallow waters down to a depth of about 59 m (194 ft). Meridiastra are morphologically similar to the Atlantic genus Asterina. They are also phylogenetically close and possibly sister genera.
