Echinasteridae | |
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Echinaster sepositus | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Echinodermata |
Class: | Asteroidea |
Order: | Spinulosida |
Family: | Echinasteridae Verrill, 1870 [1] |
Genera | |
see text | |
Synonyms [1] | |
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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.
Echinasteridae contains eight genera and about 133 species. The two genera Echinaster and Henricia are the most speciose, forming species complexes. Echinaster has a largely tropical distribution and occurs in shallow seas including continental shelves, while Henricia is cosmopolitan, occurring mostly in cold waters, including polar habitats and abyssal locations. [2] Aleutihenricia and Odontohenricia are native to the northeastern Pacific Ocean, in the vicinity of the Aleutian Islands. [3]
Echinasterids are mostly five-armed starfish with thick but small discs, and long, slender, often cylindrical arms. The cuticle is covered on both the aboral (upper) and oral (lower) surfaces by a latticework of ossicles which are either flattened or rounded plates, or pseudopaxilliform (peglike) plates with broad bases. The mouth is surrounded by tight-fitting triangular plates. The pores through which the tube feet project are small and the plates on either side of the ambulacral grooves are angular and bear spines. Echinasterids do not have pedicellariae. [2]
Echinasterids are epifaunal animals that live on the seabed, on rock, sand, gravel or mud. They graze on encrusting invertebrates such as sponges, tunicates and molluscs, as well as feeding on detritus. Additionally, Echinaster uses cilia to create a current to draw zooplankton and organic particles into its mouth. Henricia is a scavenger and a filter feeder. [2]
The sexes are separate in these starfish. The eggs are large and yolky and development is by way of brachiolaria larvae. In some species these are planktonic, but in others, the females brood their young in a brood chamber under their arms. Echinaster luzonicus is renowned for shedding its arms in a process known as autotomy, being then able to regenerate a new disc from a single arm. [2] This is a form of asexual reproduction and E. luzonicus is not known to reproduce in any other way. Another echinasterid that reproduces asexually is Henricia sexradiata , but in this case, the disc also splits apart. [4]
The following genera are recognised by the World Register of Marine Species: [1]
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.
Henricia is a large genus of slender-armed sea stars belonging to the family Echinasteridae. It contains about fifty species.
Odontohenricia is a genus of starfish in the family Echinasteridae.
Luidia clathrata is a tropical species of starfish in the family Luidiidae. It is variously known as the slender-armed starfish, the gray sea star, or the lined sea star. It is found in the western Atlantic Ocean.
Archaster typicus is a species of starfish in the family Archasteridae. It is commonly known as the sand star or the sand sifting star but these names are also applied to starfish in the genus Astropecten. It is found in shallow waters in the Indo-Pacific region.
The orange knobby star, Echinaster echinophorus, is a species of sea star found in the Caribbean Sea and along the Atlantic coast of South America.
Echinaster spinulosus, the small spine sea star, is a species of sea star found in shallow parts of the western Atlantic Ocean, the Caribbean Sea and Gulf of Mexico.
Poraniidae is a family of starfishes in the order Valvatida.
Metrodira subulata is a species of starfish in the family Echinasteridae. It is found on the seabed in shallow parts of the Indo-Pacific region.
Aleutihenricia is a genus of starfish in the family Echinasteridae in the order Spinulosida.
Henricia lisa is a species of starfish in the family Echinasteridae found in deep water in the northern Atlantic Ocean.
Luidia magellanica is a species of starfish in the family Luidiidae. It is found in the southeastern Pacific Ocean on the coast of South America.
Echinaster luzonicus, the Luzon sea star, is a species of starfish in the family Echinasteridae, found in shallow parts of the western Indo-Pacific region. It sometimes lives symbiotically with a copepod or a comb jelly, and is prone to shed its arms, which then regenerate into new individuals.
Henricia sexradiata is a species of starfish in the family Echinasteridae. It is native to the western Atlantic Ocean and the Gulf of Mexico.
Echinaster callosus, the warty sea star or the banded bubble star, is a species of starfish found in shallow parts of the western Indo-Pacific region. The disc and five slender arms are covered with white, pink, red or violet warts, often forming transverse bands of colour on the arms.
Henricia oculata, commonly known as the bloody Henry starfish, is a species of starfish in the family Echinasteridae. It is native to northwestern Europe. It was first described as Asterias oculata by the British zoologist Thomas Pennant in 1777, later being transferred to the genus Henricia.
Coscinasterias muricata is a species of starfish in the family Asteriidae. It is a large 11-armed starfish and occurs in shallow waters in the temperate western Indo-Pacific region.
Echinaster is a well-studied and common genus of starfish containing ~30 species and is the second-largest genus found within the family Echinasteridae. The genera Henricia and Echinaster encompass 90% of all the species found within the family Echinasteridae. It contains 30 species, however the number of species in this genus is still debatable because of uncertainty within the genera. This genus is currently sub-divided into two sub-genera: Echinaster and Othilia, evolutionary relationships between the sub-genera is not understood. Echinaster are found in the Pacific, Atlantic and Indian oceans, with most species being studied in the Gulf of Mexico and Brazil. The sub-genera Othilia is thought to encompass species mainly found in the Gulf of Mexico and Brazil. Echinaster is often one of the most studied species within the family Echinasteridae and is often used to find evolutionary relationships.