The Valvatida are an order of

starfish 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 ...

in the

class Class or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used differentl ...

Asteroidea 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 ...

, which contains 695

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

in 172

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

in 17

families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideall ...

Description

The order encompasses both tiny species, which are only a few

millimetre 330px, Different lengths as in respect to the electromagnetic spectrum, measured by the metre and its derived scales. The microwave is between 1 meter to 1 millimeter. The millimetre (American and British English spelling differences#-re, -er, ...

s in diameter, like those in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

'' Asterina'', and species which can reach up to 75 cm, such as species in the genus '' Thromidia''. Almost all species in this order have five arms with

tube feet Tube feet (technically podia) are small active tubular projections on the oral face of an echinoderm, whether the arms of a starfish, or the undersides of sea urchins, sand dollars and sea cucumbers; they are more discreet though present on britt ...

. This order is primarily identified by the presence of conspicuous marginal

ossicles The ossicles (also called auditory ossicles) are three bones in either middle ear that are among the smallest bones in the human body. They serve to transmit sounds from the air to the fluid-filled labyrinth (cochlea). The absence of the auditory ...

, which characterize most of the species. Most members of this order have five arms and two rows of tube feet with suckers. Some species have paxillae and in some, the main

pedicellaria A pedicellaria (plural: pedicellariae) is a small wrench- or claw-shaped appendage with movable jaws, called valves, commonly found on echinoderms (phylum Echinodermata), particularly in sea stars (class Asteroidea) and sea urchins (class Echi ...

e are clamp-like and recessed into the skeletal plates. This group includes the

cushion star ''Culcita novaeguineae'' (common name, cushion star) is a species of starfish. It has short arms and an inflated appearance and resembles a pentagonal pincushion. It is variable in colour and can be found in tropical warm waters in the Indo-P ...

, and the

leather star The leather star (''Dermasterias imbricata'') is a sea star in the family Asteropseidae found at depths to off the western seaboard of North America. It was first described to science by Adolph Eduard Grube in 1857. Description The leather st ...

Families

According to the

World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialist ...

, the following families are included in Valvatida: * family

Acanthasteridae ''Acanthaster'' is a bitypic genus of large and venomous starfish placed in its own family, Acanthasteridae. Its two members are known as crown-of-thorns starfish. Acanthaster are native to coral reefs in Indo-Pacific region. The species in ...

Gervais, 1841 * family Archasteridae Viguier, 1878 * family

Asterinidae The Asterinidae are a large family of sea stars in the order Valvatida. Description and characteristics These are generally small sea stars, flattened dorsally and bearing very short arms, often giving a pentagonal shape in the body ;example: ...

Gray, 1840 * family

Asterodiscididae Asterodiscididae is a family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of ...

Rowe, 1977 * family

Asteropseidae Asteropseidae is a family of sea stars 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 ...

Hotchkiss & Clark, 1976 * family

Chaetasteridae Chaetasteridae is a family of echinoderms belonging to the order Valvatida The Valvatida are an order of starfish in the class Asteroidea, which contains 695 species in 172 genera in 17 families. Description The order encompasses both tiny ...

Sladen, 1889 * family

Ganeriidae Ganeriidae is a family of echinoderms belonging to the order Valvatida The Valvatida are an order of starfish in the class Asteroidea, which contains 695 species in 172 genera in 17 families. Description The order encompasses both tiny spe ...

Sladen, 1889 * family

Goniasteridae Goniasteridae (the biscuit stars) 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. Description Goniast ...

Forbes, 1841 * family

Leilasteridae Leilasteridae is a family of echinoderms belonging to the order Valvatida The Valvatida are an order of starfish in the class Asteroidea, which contains 695 species in 172 genera in 17 families. Description The order encompasses both tiny ...

Jangoux & Aziz, 1988 * family

Mithrodiidae The Mithrodiidae is a family of starfish in the order Valvatida. Members of this family are big to huge tropical sea stars with 5 arms, rounded in cross-section. List of genera and species * Genus '' Mithrodia'' Gray, 1840 ** '' Mithrodia br ...

Viguier, 1878 * family Odontasteridae Verrill, 1899 * family Ophidiasteridae Verrill, 1870 * family

Oreasteridae The Oreasteridae are a family of sea stars in the class Asteroidea. Description and characteristics This family contains many species of regular starfishes with usually 5 arms around a stiff, convex and often brightly colored body. Whereas som ...

Fisher, 1911 * family Podosphaerasteridae Fujita & Rowe, 2002 * family Poraniidae Perrier, 1875 * family

Solasteridae The Solasteridae are a family of sea stars. Genera The following genera are listed in the World Register of Marine Species: * '' Crossaster'' Müller and Troschel, 1840 * '' Heterozonias'' Fisher, 1910 * '' Laetmaster'' Fisher, 1908 * '' Lop ...

Viguier, 1878 * family Sphaerasteridae Schöndorf, 1906 † Image:Crown of Thorns-jonhanson.jpg, ''

Acanthaster planci The crown-of-thorns starfish (frequently abbreviated to COTS), ''Acanthaster planci'', is a large starfish that preys upon hard, or stony, coral polyps (Scleractinia). The crown-of-thorns starfish receives its name from venomous thorn-like spines ...

'', an

Image:Bantayan starfish.JPG, '' Archaster typicus'', an Archasteridae Image:Bat Star (Asterina miniata)002.jpg, '' Asterina miniata'', an

Image:Firebrick Starfish (Asterodiscides truncatus).jpg, '' Asterodiscides truncatus'', an

Image:Leather star fish.jpg, ''

Dermasterias imbricata The leather star (''Dermasterias imbricata'') is a sea star in the family Asteropseidae found at depths to off the western seaboard of North America. It was first described to science by Adolph Eduard Grube in 1857. Description The leather st ...

'', an

Image:Chaetaster longipes.jpg, '' Chaetaster longipes'', a

Image:Pentagonaster dubeni 1.jpg, '' Pentagonaster dubeni'', a

Image:Leilaster radians 2.jpg, '' Leilaster radians'', a

Image:Mithrodia clavigera FLMNH.jpg, '' Mithrodia clavigera'', a

Image:Odontaster penicillatus MNHN.jpg, '' Odontaster penicillatus'', an Odontasteridae Image:BlueSeaStar 2.jpg, ''

Linckia laevigata ''Linckia laevigata'' (sometimes called the "blue ''Linckia''" or blue star) is a species of sea star in the shallow waters of tropical Indo-Pacific. Description and characteristics The variation ("polymorphism", in this case, a "color morph" ...

'', an Ophidiasteridae Image:Starfish in Mombassa.JPG, '' Protoreaster lincki'', an

Image:Podosphaeraster gustavei.jpg, '' Podosphaeraster gustavei'', a Podosphaerasteridae Image:Porania pulvillus NOAA.jpg, '' Porania pulvillus'', a Poraniidae Image:Solaster stimpsoni.jpg, ''

Solaster stimpsoni ''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. Description ''Solaster stimpsoni'' is a large species, growing up to 5 ...

'', a

References

* Burchett M, Dando M, Waller G; ''SeaLife: A Complete Guide to the Marine Environment''; Smithsonian Institution Press, USA; , 1996.

{{Taxonbar, from=Q241493 Valvatida,