| Orthasterias | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Asteroidea |
| Order: | Forcipulatida |
| Family: | Asteriidae |
| Genus: | Orthasterias Verrill, 1867 [1] |
| Species: | O. koehleri |
| Binomial name | |
| Orthasterias koehleri (deLoriol, 1897) [2] | |
| Synonyms [2] | |
| |
Orthasterias is a genus of sea stars in the family Asteriidae. Orthasterias koehleri, the rainbow star or red-banded sea star, is the only species in the genus. It is found in the North Pacific Ocean.
The rainbow star is a large starfish, growing to a diameter of about 50 centimetres (20 in) with an arm length of 21 centimetres (8.3 in). It usually has five slender tapering arms and the aboral (upper) surface is pink or red with irregular patches or bands of darker red, orange or grey. The surface is covered with sharp white or mauve spines, each surrounded by a ring of pedicellariae, tiny pincer-like organs. [3] [4]
The rainbow star is found in northern parts of the Pacific Ocean with its range extending from California to Alaska at depths down to about 250 metres (820 ft). [3] It also occurs in mid-ocean on knolls and seamounts. [2] It is an uncommon species and is usually found on soft bottoms of mud or sand, or on kelp or rock surfaces. [3]
The rainbow star is a predator and feeds on a range of invertebrates including gastropod molluscs, limpets, bivalves, brachiopods, chitons, barnacles and tunicates. [4] In Alaska, it especially favours the ribbed clam Humilaria kennerleyi . [5] It can dig up clams buried in the substrate and force the valves apart with the suction provided by its tube feet. It then everts part of its stomach, thrusting a fold inside the bivalve and excreting digestive enzymes onto the tissues. When these have liquefied sufficiently, the stomach engulfs them and is returned to its normal position inside the starfish. [3] [6]
The rainbow star is sometimes attacked by a voracious predator, the morning sun star (Solaster dawsoni). It attempts to defend itself by winding its arms round the attacker and nipping it with its thousands of pedicellariae. [7]
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.
Solaster paxillatus, the orange sun star, is a species of starfish found at varying depths in the northern Pacific Ocean. It is a natural predator of the starfish Asterias amurensis.
The Brisingids are deep-sea-dwelling starfish in the order Brisingida.
The leather star is a sea star in the family Asteropseidae found at depths to 100 m (328 ft) off the western seaboard of North America. It was first described to science by Adolph Eduard Grube in 1857.
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.
Luidia magnifica, the magnificent star, is a species of starfish in the family Luidiidae. It is found in the Pacific Ocean.
Solaster stimpsoni, common names Stimpson's sun star, sun star, orange sun star, striped sunstar, and sun sea star, is a species of starfish in the family Solasteridae.
Solaster dawsoni, the morning sun star, is a species of starfish in the family Solasteridae. It is found on either side of the northern Pacific Ocean. It has two subspecies:
The purple sunstar, northern sunstar, or smooth sun star, Solaster endeca, is a species of starfish in the family Solasteridae.
Asterias forbesi, commonly known as Forbes sea star, is a species of starfish in the family Asteriidae. It is found in shallow waters in the northwest Atlantic Ocean and the Caribbean Sea.
Evasterias troschelii is a species of starfish in the family Asteriidae. Its common names include the mottled star, false ochre sea star and Troschel's true star. It is found in Kamchatka and the north western coast of North America.
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.
Stylasterias is a genus of starfish in the family Asteriidae. Stylasterias forreri, the velcro star, is the only species in the genus. It is found on the Pacific coast of Canada and the United States.
Pteraster tesselatus, the slime star or cushion star, is a species of starfish in the family Pterasteridae found in the North Pacific.
Luidia foliolata, the sand star, is a species of starfish in the family Luidiidae found in the northeastern Pacific Ocean on sandy and muddy seabeds at depths to about 600 m (2,000 ft).
Leptasterias tenera is a species of starfish in the family Asteriidae. It is found on the eastern coast of North America.
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.
Sea star wasting disease or starfish wasting syndrome is a disease of starfish and several other echinoderms that appears sporadically, causing mass mortality of those affected. There are approximately 40 species of sea stars that have been affected by this disease. At least 20 of these species were on the Northwestern coast of Mexico to Alaska. The disease seems to be associated with increased water temperatures in some locales, but not others. It starts with the emergence of lesions, followed by body fragmentation and death. In 2014 it was suggested that the disease is associated with a single-stranded DNA virus now known as the sea star-associated densovirus (SSaDV). However, this hypothesis was refuted by recent research in 2018 and 2020. Sea star wasting disease is still not fully understood.
Marthasterias is a genus of starfish in the family Asteriidae. Both species in the genus are commonly known as the spiny starfish.
Rathbunaster is a monospecific genus of sea stars in the family Asteriidae. The genus name was given by Walter Kenrick Fisher to honor the starfish biologist Richard Rathbun of the Smithsonian Institution. He originally ranged this genus under the family Pycnopididae, synonymous with Asteriidae.