| Xyloplax turnerae | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Asteroidea |
| Order: | Peripodida |
| Family: | Xyloplacidae |
| Genus: | Xyloplax |
| Species: | X. turnerae |
| Binomial name | |
| Xyloplax turnerae Rowe, Baker & Clark, 1988 [1] | |
Xyloplax turnerae is a sea daisy, a member of an unusual group of marine taxa belonging to the phylum Echinodermata. It has been found living on decaying timber in a deep oceanic trench in the Bahamas.
An enigmatic new species of echinoderm, Xyloplax medusiformis, was discovered in the South Pacific near New Zealand and first described in 1986 by Baker, Rowe and Clark. Further deep sea exploration by the same team using a submersible vehicle led to the discovery of a new species of Xyloplax . Pieces of timber were deposited at a depth of 2,066 metres (6,778 ft) in an oceanic trench known as the Tongue of the Ocean between the Bahamian islands of Andros and New Providence. When recovered nearly two years later they yielded more than two hundred specimens of Xyloplax turnerae. [2] In 2004, another species in this genus was collected in a similar way from a depth of 2,675 metres (8,776 ft) in the north east Pacific Ocean. It has since been named Xyloplax janetae . [3]
Xyloplax turnerae is very much like Xyloplax medusiformis in appearance. It is shaped like a flattened disc and is fringed by a row of short spines which are all of approximately equal length in the range 300–400 μm. [3] The aboral (upper) surface is clad in a series of concentric plates each bearing three spines. The tube feet have rounded bulbous tips. [3] On the oral (lower) side the mouth leads to an eversible stomach but there is no gut or anus. There is a single row of tube feet circling the mouth and these number up to 110 while X. medusiformis has fewer than 65. The females grow to about 12 millimetres (0.47 in) in diameter and the males to 7 millimetres (0.28 in). All the embryos found in the females were small, less than 180 μm in diameter, and it seems unlikely that this species broods its young in the same way that X. medusiformis does. The marginal spines are mobile and are disproportionally longer in smaller individuals than they are in larger ones. It is thought that juveniles may use them to "parachute" and that this may aid in their dispersal. [2]
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 1,500 species of starfish occur on the seabed in all the world's oceans, from the tropics to frigid polar waters. They are found from the intertidal zone down to abyssal depths, 6,000 m (20,000 ft) below the surface.
The Valvatida are an order of starfish in the class Asteroidea, which contains 695 species in 172 genera in 17 families.
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.
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.
Culcita is a genus of cushion stars. They are found in tropical waters. Some are kept in home aquariums.
The common sunstar or Crossaster papposus is a species of sea star belonging to the family Solasteridae. It is found in the northern parts of both the Atlantic and the Pacific Oceans.
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.
Xyloplax janetae is a Xyloplax of the family Xyloplacidae. It lives on the surface of wood sunken to abyssal depths.
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.
Luidia senegalensis, the nine-armed sea star, is a tropical species of starfish in the family Luidiidae found in the western Atlantic Ocean.
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.
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.
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.
Fromia indica, commonly called Indian sea star or red starfish, is a species of marine starfish belonging to the family Goniasteridae.
Heliaster microbrachius is a species of Asteroidea in the family Heliasteridae.
Freyella elegans is a species of deep-water starfish in the family Freyellidae in the order Brisingida, living at abyssal depths in the northwestern Atlantic Ocean.