Velatida

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Velatida
Starfish at Tafelberg deep DSC09595.JPG
Pteraster capensis
Scientific classification
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Order:
Velatida

Perrier, 1884
Families
4, see text.

The Velatida are an order of sea stars containing about 200 species in five families. These sea stars normally have thick bodies with large discs. [1]

Contents

Description and characteristics

This order contains mostly deep or cold seas sea stars, often with a wide distribution (sometimes global). They have a pentagonal or star shape, with between 5 and 15 arms. Their skeleton is weakly developed, which confers them a good flexibility, and numerous papillae on the aboral surface allow them to breathe in poorly oxygenated waters. Their pedicellariae are often provided with spines. The smallest are Caymanostellidae (between 0,5 and 3 cm) and the biggest Pterasteridae (up to 30 cm). [2]

Taxonomy

New molecular evidence now suggests a relationship between some velatid and valvatid families.

List of families according to World Register of Marine Species: [3]

Related Research Articles

Crinoid Class of echinoderms

Crinoids are marine animals that make up the class Crinoidea, one of the classes of the phylum Echinodermata, which also includes the starfish, brittle stars, sea urchins and sea cucumbers. Those crinoids which, in their adult form, are attached to the sea bottom by a stalk are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, being members of the largest crinoid order, Comatulida.

Starfish Class of echinoderms, marine animal

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.

Sea cucumber Class of echinoderms

Sea cucumbers are echinoderms from the class Holothuroidea. They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide. The number of holothurian species worldwide is about 1,717 with the greatest number being in the Asia Pacific region. Many of these are gathered for human consumption and some species are cultivated in aquaculture systems. The harvested product is variously referred to as trepang, namako, bêche-de-mer or balate. Sea cucumbers serve a useful role in the marine ecosystem as they help recycle nutrients, breaking down detritus and other organic matter after which bacteria can continue the degradation process.

Brittle star Class of brittle stars

Brittle stars, serpent stars, or ophiuroids are echinoderms in the class Ophiuroidea closely related to starfish. They crawl across the sea floor using their flexible arms for locomotion. The ophiuroids generally have five long, slender, whip-like arms which may reach up to 60 cm (24 in) in length on the largest specimens. From New Latin ophiurus, from Ancient Greek ὄφις + οὐρά.

Valvatida Order of starfishes

The Valvatida are an order of starfish in the class Asteroidea, which contains 695 species in 172 genera in 17 families.

Asterinidae Family of starfishes

The Asterinidae are a large family of sea stars in the order Valvatida.

Gobiiformes Order of fishes

The Gobiiformes are an order of fish that includes the gobies and their relatives. The order, which was previously considered a suborder of Perciformes, is made up of about 2,211 species that are divided between seven families. Phylogenetic relationships of the Gobiiformes have been elucidated using molecular data. Gobiiforms are primarily small species that live in marine water, but roughly 10% of these species inhabit fresh water. This order is composed chiefly of benthic or burrowing species; like many other benthic fishes, most gobiiforms do not have a gas bladder or any other means of controlling their buoyancy in water, so they must spend most of their time on or near the bottom. Gobiiformes means "Goby-like".

Goniasteridae Family of starfishes

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.

Forcipulatida Order of starfishes

The Forcipulatida are an order of sea stars, containing three families and 49 genera.

Spinulosida Order of starfishes

The Spinulosida are an order of sea stars containing at least 120 species in seven genera and two families.

Notomyotida Order of starfishes

The Notomyotida are an order of sea stars containing at least 75 species in eight genera of the monotypic family, Benthopectinidae.

Brisingida Order of starfishes

The Brisingids are deep-sea-dwelling starfish in the order Brisingida.

Coastal fish

Coastal fish, also called inshore fish or neritic fish, inhabit the sea between the shoreline and the edge of the continental shelf. Since the continental shelf is usually less than 200 metres deep, it follows that pelagic coastal fish are generally epipelagic fish, inhabiting the sunlit epipelagic zone. Coastal fish can be contrasted with oceanic fish or offshore fish, which inhabit the deep seas beyond the continental shelves.

<i>Henricia</i> Genus of starfishes

Henricia is a large genus of slender-armed sea stars belonging to the family Echinasteridae. It contains about fifty species.

Caymanostellidae is a family of sea stars containing six species in two families. These asteroids normally have thick bodies with large discs.

Pterasteridae Family of starfishes

Pterasteridae is a family of sea stars in the order Velatida, consisting of eight genera.

Myxasteridae Family of starfishes

Myxasteridae is a family of deep-sea velatid sea stars containing nine species in three genera.

Stichasteridae Family of starfishes

The Stichasteridae are a small family of Asteroidea in the order Forcipulatida. Genera were formerly unassigned, or in the family Asteriidae.

Korethrasteridae Family of starfishes

Korethrasteridae is a family of starfish in the order Velatida. It contains the following genera and species:

<i>Euretaster insignis</i> Species of starfish

Euretaster insignis, commonly known as the striking sea star, is a species of starfish in the family Pterasteridae found in the central west Pacific Ocean. It is one of only three species in the order Velatida to be found in shallow water in the tropics. The young are brooded in a cavity underneath a "supradorsal" membrane.

References

  1. "Asterozoa: Fossil groups: SciComms 05-06: Earth Sciences". Palaeo.gly.bris.ac.uk. 2005-11-22. Retrieved 2010-07-30.
  2. Mah, Christopher L. "Velatida". www.accessscience.com.
  3. "The World Asteroidea Database - Velatida". Marinespecies.org. Retrieved 2010-07-30.