![Nerr0878](https://upload.wikimedia.org/wikipedia/commons/e/e9/Nerr0878.jpg)
This List of echinoderm orders concerns the various classes and orders into which
taxonomists
In biology, taxonomy () is the scientific study of naming, defining ( circumscribing) and classifying groups of biological organisms based on shared characteristics. Organisms are grouped into taxa (singular: taxon) and these groups are given ...
categorize the roughly 7000 extant species
as well as the extinct
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 ...
of the exclusively marine phylum
Echinodermata
An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea li ...
.
Subphylum
Crinozoa
Crinozoa is a subphylum of mostly sessile echinoderms, of which the crinoids, or sea lilies, are the only extant members. Crinozoans have an extremely extensive fossil history, which may or may not extend into the Precambrian (provided the enigm ...
Class
Crinoidea
Crinoids are marine animals that make up the class Crinoidea. Crinoids that are attached to the sea bottom by a stalk in their adult form are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, which are ...
![Crinoid on the reef of Batu Moncho Island](https://upload.wikimedia.org/wikipedia/commons/d/d2/Crinoid_on_the_reef_of_Batu_Moncho_Island.JPG)
* Subclass
Articulata (540 species)
** Order
Bourgueticrinida
Bourgueticrinida is an order of crinoids that typically live deep in the ocean. Members of this order are attached to the seabed by a slender stalk and are known as sea lilies. While other groups of crinoids flourished during the Permian, bourgu ...
** Order
Comatulida
Comatulida is an order of crinoids. Members of this order are known as feather stars and mostly do not have a stalk as adults. The oral surface with the mouth is facing upwards and is surrounded by five, often divided rays with feathery pinnules ...
** Order
Cyrtocrinida
Cyrtocrinida is an order of sea lilies which contains two suborders and three families.
Characteristics
Members of this order have stems consisting of a single skeletal unit or a very small number of units. There are no cirri, and the expanded ...
** Order
Hyocrinida
Hyocrinida is an order of sea lilies which contains a single extant family, Hyocrinidae
''Hyocrinidae'' is a family of echinoderms belonging to the order Hyocrinida.
Genera:
* ''Ailsacrinus'' Mironov & Sorokina, 1998
* ''Anachalypsicrinus'' A ...
** Order
Isocrinida
Isocrinida is an order of sea lilies which contains four extant families.
Characteristics
Members of this order are characterised by having a "heteromorphic" stalk; the stalk consists of a series of nodes with cirri, interspersed by several node ...
** Order
Millericrinida
Millericrinida is an order of articulate crinoids that originated in the Anisian
In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from million years ago until millio ...
* Subclass †
Flexibilia
Flexibilia is a superorder of specialized Paleozoic (Middle Ordovician to Permian) crinoids. They exhibited a conserved body plan and consistent suite of characteristics throughout their long history. Previously considered a subclass with uncle ...
* Subclass †
Camerata
* Subclass †
Disparida
Disparida is an parvclass of extinct marine animals in the class Crinoidea. Disparids are a speciose and morphologically diverse group of crinoids distinguished by their monocyclic calyx and slender arms without pinnules. They range from the Earl ...
Image:Comaster schlegelii.JPG, ''Comaster schlegelii
''Comaster schlegelii'', the variable bushy feather star, is a crinoid in the family Comatulidae. It was previously classified as ''Comanthina schlegeli'' but further research showed that it was better placed in the genus ''Comaster''. It is fou ...
'' (Comatulida
Comatulida is an order of crinoids. Members of this order are known as feather stars and mostly do not have a stalk as adults. The oral surface with the mouth is facing upwards and is surrounded by five, often divided rays with feathery pinnules ...
)
Image:Holopus 2.jpg, ''Holopus
''Holopus'' is a genus of echinoderms belonging to the family Holopodidae.
The species of this genus are found in Central America, Pacific Ocean (near Australia).
Species:
*''Holopus alidis''
*''Holopus mikihe''
*''Holopus rangii
''Holopus ...
sp.'' (Cyrtocrinida
Cyrtocrinida is an order of sea lilies which contains two suborders and three families.
Characteristics
Members of this order have stems consisting of a single skeletal unit or a very small number of units. There are no cirri, and the expanded ...
)
Image:Encrinus liliiformis 4.JPG, '' Encrinus liliiformis'' ( Encrinida)
Image:Calamocrinus diomedæ (Plate XXVIII) BHL4232451.jpg, '' Calamocrinus diomedae'' (Hyocrinida
Hyocrinida is an order of sea lilies which contains a single extant family, Hyocrinidae
''Hyocrinidae'' is a family of echinoderms belonging to the order Hyocrinida.
Genera:
* ''Ailsacrinus'' Mironov & Sorokina, 1998
* ''Anachalypsicrinus'' A ...
)
Image:Proisocrinus ruberrimus.jpg, ''Proisocrinus ruberrimus
''Proisocrinus ruberrimus'' is a species of crinoids that is in the monotypic genus ''Proisocrinus''. The genus is in the monotypic family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) ...
'' (Isocrinida
Isocrinida is an order of sea lilies which contains four extant families.
Characteristics
Members of this order are characterised by having a "heteromorphic" stalk; the stalk consists of a series of nodes with cirri, interspersed by several node ...
)
Image:Liliocrinus polydactylus MHNT.jpg, '' Liliocrinus polydactylus'' (Millericrinida
Millericrinida is an order of articulate crinoids that originated in the Anisian
In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from million years ago until millio ...
)
Class
Paracrinoid
Paracrinoidea is an extinct class of blastozoan echinoderms. They lived in shallow seas during the Early Ordovician through the Early Silurian. While blastozoans are usually characterized by types of respiratory structures present, it is not clea ...
ea †
No orders, 13 to 15 genera are known.
* order
Comarocystitida †
** ?Family
Heckeritidae †
*** ''
Heckerites'' †
** Family
Amygdalocystitidae †
*** ''
Achradocystites'' † Volborth, 1870
*** ''
Amygdalocystites'' † Billings, 1854 (= ''Ottawacystis'') (?= ''Billingsocystis'')
*** ''
Oklahomacystis'' † Parsley & Mintz, 1975 (Bassler, 1943)
*** ''
Ovulocystites'' † Frest et al., 1980
** Family
Comarocystitidae † Balther, 1899
*** ''
Comarocystites'' † Billings, 1854
*** ''
Implicaticystis'' †
*** ''
Sinclairocystis'' †
* order
Platycystitida †
** Family
Platycystitidae †
*** ''
Canadocystis'' † (= ''Sigmacystis'')
*** ''
Platycystites'' †
** Family
Malocystitidae †
*** ''
Malocystites'' †
*** ''
Wellerocystis'' †
** Family
Bistomiacystitidae †
*** ''
Bistomiacystis'' †
Doubtful paracrinoids:
* ''Columbocystis''
* ''Foerstecystis''
* ''Springerocystis''
* ''Ulrichocystis''
* ''Paleocystites''
* ''Allocystites''
Class
Cystoidea
Cystoidea is a class of extinct crinozoan echinoderms, termed cystoids, that lived attached to the sea floor by stalks. They existed during the Paleozoic Era, in the Middle Ordovician and Silurian Periods, until their extinction in the Devonian ...
†
* order
Aristocystitida †
* order
Asteroblastida †
* order
Glyptosphaeritida †
* order
Sphaeronitida †
Class
Edrioasteroidea
Edrioasteroidea is an extinct class of echinoderms. The living animal would have resembled a pentamerously symmetrical disc or cushion. They were obligate encrusters and attached themselves to inorganic or biologic hard substrates (frequently har ...
†
* order
Edrioasterida
* order
Isorophida
Subphylum
Asterozoa
The Asterozoa are a subphylum in the phylum Echinodermata. Characteristics include a star-shaped body and radially divergent axes of symmetry. The subphylum includes the class Asteroidea (the starfish), the class Ophiuroidea (the brittle stars ...
Class Ophiuroidea (
Brittle star
Brittle stars, serpent stars, or ophiuroids (; ; referring to the serpent-like arms of the brittle star) are echinoderms in the class Ophiuroidea, closely related to starfish. They crawl across the sea floor using their flexible arms for locomo ...
s)
** Order
Euryalida
The Euryalida are an order of brittle stars, which includes large species with either branching arms (called "basket stars") or long and curling arms (called "snake stars").
Characteristics
Many of the species in this order have characteristi ...
** Order
Ophiurida
The Ophiurida are an order of echinoderms within the class Ophiuroidea. It includes the vast majority of living brittle stars.
Characteristics
Ophiurida have bursae for respiration and excretion, and dorsal and ventral arm shields are present a ...
** Order
Amphilepidida
Amphilepidida is an order of echinoderms belonging to the class Ophiuroidea
Brittle stars, serpent stars, or ophiuroids (; ; referring to the serpent-like arms of the brittle star) are echinoderms in the class Ophiuroidea, closely related to ...
** Order
Ophiacanthida
Ophiacanthida is an order of echinoderms belonging to the class Ophiuroidea.
Families:
* Ophiodermatina Ljungman, 1867
** Ophiodermatidae
** Ophiomyxidae
** Ophiopezidae
** Ophiocomidae
Ophiocomidae are a family of brittle stars of the sub ...
** Order
Ophioleucida
** Order
Ophioscolecida
Ophioscolecida is an order of echinoderms belonging to the class Ophiuroidea
Brittle stars, serpent stars, or ophiuroids (; ; referring to the serpent-like arms of the brittle star) are echinoderms in the class Ophiuroidea, closely related to ...
Image:Basket star feeding at night at the Red Sea.JPG, ''Astroboa nuda
''Astroboa nuda'' is a type of basket star from Gorgonocephalidae family.
Its large arms (up to armspread) are highly branched. It inhabits reef slopes exposed to current in diverse places such as the Red Sea
The Red Sea ( ar, البح ...
'' (Euryalida
The Euryalida are an order of brittle stars, which includes large species with either branching arms (called "basket stars") or long and curling arms (called "snake stars").
Characteristics
Many of the species in this order have characteristi ...
)
Image:Ophiura ophiura.jpg, ''Ophiura ophiura
''Ophiura ophiura'' or the serpent star is a species of brittle star in the order Ophiurida. It is typically found on coastal seabeds around northwestern Europe.
Description
''Ophiura ophiura'' has a circular central disc up to 35 mm (1.5 ...
'' (Ophiurida
The Ophiurida are an order of echinoderms within the class Ophiuroidea. It includes the vast majority of living brittle stars.
Characteristics
Ophiurida have bursae for respiration and excretion, and dorsal and ventral arm shields are present a ...
)
Image:Ophiolepis elegans 600.jpg, '' Ophiolepis elegans'' (Amphilepidida
Amphilepidida is an order of echinoderms belonging to the class Ophiuroidea
Brittle stars, serpent stars, or ophiuroids (; ; referring to the serpent-like arms of the brittle star) are echinoderms in the class Ophiuroidea, closely related to ...
)
Image:Ophiure noire à la Réunion.JPG, ''Ophiocoma erinaceus
''Ophiocoma erinaceus'' is a species of echinoderms belonging to the family Ophiocomidae
Ophiocomidae are a family of brittle stars of the suborder Ophiurina.
Systematics and phylogeny
Ophiocomidae has been placed (along with Ophionereidid ...
'' (Ophiacanthida
Ophiacanthida is an order of echinoderms belonging to the class Ophiuroidea.
Families:
* Ophiodermatina Ljungman, 1867
** Ophiodermatidae
** Ophiomyxidae
** Ophiopezidae
** Ophiocomidae
Ophiocomidae are a family of brittle stars of the sub ...
)
Image:Ophioleuce seminudum (MNHN-IE-2013-10292) 02.jpg, '' Ophioleuce seminudum'' ( Ophioleucida)
Image:Ophiomyces frutectosus (MNHN-IE-2013-10282) 02.jpg, '' Ophiomyces frutectosus'' (Ophioscolecida
Ophioscolecida is an order of echinoderms belonging to the class Ophiuroidea
Brittle stars, serpent stars, or ophiuroids (; ; referring to the serpent-like arms of the brittle star) are echinoderms in the class Ophiuroidea, closely related to ...
)
Class Asteroidea (
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 ...
)
*Infraclass
Concentricycloidea
Sea daisies (infraclass Concentricycloidea; order Peripodida) make up an unusual group of deep-sea taxa belonging to the phylum Echinodermata, with three species described in the genus ''Xyloplax''. Intestine and anus are absent.
Distribution
S ...
**
Peripodida
Sea daisies (infraclass Concentricycloidea; order Peripodida) make up an unusual group of deep-sea taxa belonging to the phylum Echinodermata, with three species described in the genus ''Xyloplax''. Intestine and anus are absent.
Distribution
...
*Superorder
Forcipulatacea
The Forcipulatacea are a superorder of sea stars. Subdivision
* order Forcipulatida
* order Brisingida
The Brisingids are deep-sea-dwelling starfish in the order Brisingida.
Description
These starfish have between 6 to 18 long, attenuated ...
**
Brisingida
The Brisingids are deep-sea-dwelling starfish in the order Brisingida.
Description
These starfish have between 6 to 18 long, attenuated arms which they use for suspension feeding. Other characteristics include a single series of marginals, a f ...
**
Forcipulatida
The Forcipulatida are an order of sea stars, containing three families and 49 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 bio ...
*Superorder
Spinulosacea
**
Spinulosida
The Spinulosida are an order of sea stars containing at least 120 species in seven genera and one family.
Spinulosids completely lack pedicellariae and have a delicate skeletal arrangement. Their name comes from the presence of numerous low spi ...
*Superorder
Valvatacea
**
Notomyotida
Benthopectinidae is a family of sea stars containing at least 75 species in eight genera. It is the only family in the monotypic
In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. ...
**
Paxillosida
The Paxillosida are a large order (biology), order of sea stars.
Characteristics
Paxillosida adults lack an anus and have no suckers on their tube feet. They do not develop the brachiolaria stage in their early development.Matsubara, M., Komatsu ...
**
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 species, which are only a few millimetres in diameter, like those in the genu ...
*
Velatida
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.
Description and characteristics
This order contains mostly deep or cold seas sea stars, often w ...
* †
Calliasterellidae
* †
Trichasteropsida
Image:Xyloplax janetae.jpg, ''Xyloplax janetae
''Xyloplax janetae'' is a ''Xyloplax'' of the family Xyloplacidae. It lives on the surface of wood sunken to abyssal depths.
Morphology
''Xyloplax janetae'' is a flattened disk, from in diameter, and about thick. It has adambulacral spines wh ...
'' (Peripodida
Sea daisies (infraclass Concentricycloidea; order Peripodida) make up an unusual group of deep-sea taxa belonging to the phylum Echinodermata, with three species described in the genus ''Xyloplax''. Intestine and anus are absent.
Distribution
...
)
Image:Brisingid Seastar (Novodinia antillensis).jpg, '' Novodinia antillensis'' (Brisingida
The Brisingids are deep-sea-dwelling starfish in the order Brisingida.
Description
These starfish have between 6 to 18 long, attenuated arms which they use for suspension feeding. Other characteristics include a single series of marginals, a f ...
)
Image:Starfish, Oregon coast.jpg, ''Pisaster ochraceus
''Pisaster ochraceus'', generally known as the purple sea star, ochre sea star, or ochre starfish, is a common seastar found among the waters of the Pacific Ocean. Identified as a keystone species, ''P. ochraceus'' is considered an important indi ...
'' (Forcipulatida
The Forcipulatida are an order of sea stars, containing three families and 49 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 bio ...
)
Image:Echinaster sepositus Banyuls 03.jpg, ''Echinaster sepositus
''Echinaster sepositus'', the Mediterranean red sea star (sometimes only red sea star, but this name is also used for other species), is a species of starfish from the East Atlantic, including the Mediterranean Sea.Villamor, A.; and M. A. Becerr ...
'' (Spinulosida
The Spinulosida are an order of sea stars containing at least 120 species in seven genera and one family.
Spinulosids completely lack pedicellariae and have a delicate skeletal arrangement. Their name comes from the presence of numerous low spi ...
)
Image:Cheiraster echinulatus.jpg, '' Cheiraster echinulatus'' (Notomyotida
Benthopectinidae is a family of sea stars containing at least 75 species in eight genera. It is the only family in the monotypic
In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. ...
)
Image:Astropecten aranciacus Sardegna09 28cm 5520.jpg, ''Astropecten aranciacus
''Astropecten aranciacus'', the red comb star, is a sea star of the family Astropectinidae. It is native to the east Atlantic Ocean (Portugal to Angola) and Mediterranean Sea.
Habitat and behaviour
''Astropecten aranciacus'' lives very near the ...
'' (Paxillosida
The Paxillosida are a large order (biology), order of sea stars.
Characteristics
Paxillosida adults lack an anus and have no suckers on their tube feet. They do not develop the brachiolaria stage in their early development.Matsubara, M., Komatsu ...
)
Image:Linckia laevigata Tonga.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" ...
'' (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 species, which are only a few millimetres in diameter, like those in the genu ...
)
Image:Euretaster insignis.jpg, '' Euretaster insignis'' (Velatida
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.
Description and characteristics
This order contains mostly deep or cold seas sea stars, often w ...
)
Subphylum
Echinozoa
Echinozoa is a subphylum of free-living echinoderms in which the body is or originally was a modified globe with meridional symmetry. Echinozoans lack arms, brachioles, or other appendages, and do not at any time exhibit pinnate structure. Their t ...
Class Echinoidea (
Sea urchin
Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) of ...
s)
![Strongylocentrotus purpuratus 1](https://upload.wikimedia.org/wikipedia/commons/f/f4/Strongylocentrotus_purpuratus_1.jpg)
** Order
Diadematoida
** Order
Echinothurioida
The Echinothurioida are an order of sea urchins in the class Echinoidea. Echinothurioids are distinguished from other sea urchins by the combination of a flexible test and hollow spines. The membrane around the mouth contains only simple plates, ...
** Order
Pedinoida
Pedinoida is an order of sea urchins, containing the single living genus '' Caenopedina''. The group was much more diverse during the Mesozoic, and represents the oldest surviving order of euechinoid sea urchins.
They are distinguished from ...
* Superorder
Echinacea
''Echinacea'' is a genus of herbaceous flowering plants in the daisy family. It has ten species, which are commonly called coneflowers. They are found only in eastern and central North America, where they grow in moist to dry prairies and ope ...
** Order
Arbacioida
Arbacioida are an order (biology), order of sea urchins, consisting of a single family, the Arbaciidae. They are distinguished from other sea urchins by the presence of five separate plates around the anus. Unlike their close relatives, the Salen ...
** Order
Echinoida
Echinoida is an order of sea urchins in the class Echinoidea. They are distinguished from other sea urchins by simultaneously possessing both an un-sculpted test and a feeding lantern with large plates fused across the top of each pyramid.
Tax ...
** Order
Phymosomatoida
** Order
Salenioida
The Salenioida are an order of sea urchins.
Description and characteristics
They are distinguished from other sea urchins by the presence of a large plate on the upper surface, with the anus to one side. They have very large tubercles between ...
** Order
Temnopleuroida
Temnopleuridea is an infraorder of sea urchins in the order Camarodonta. They are distinguished from other sea urchins by the presence of large fused plates on top of the feeding lantern. The test is usually sculpted to some degree, and has per ...
* Superorder
Gnathostomata
Gnathostomata (; from Greek: (') "jaw" + (') "mouth") are the jawed vertebrates. Gnathostome diversity comprises roughly 60,000 species, which accounts for 99% of all living vertebrates, including humans. In addition to opposing jaws, living ...
** Order
Clypeasteroida
Sand dollars (also known as a sea cookie or snapper biscuit in New Zealand, or pansy shell in South Africa) are species of flat, burrowing sea urchins belonging to the order Clypeasteroida. Some species within the order, not quite as flat, are k ...
(sand dollars)
** Order
Holectypoida
The Holectypoida are an order of sea urchins related to the sand dollars. The order consists of just two living genera, but was once more diverse.
Description and characteristics
In appearance, the living holectypoids are similar to sand dolla ...
* Superorder
Atelostomata
The Atelostomata are a type of sea urchins. They are distinguished from other sea urchins by their irregular shape and the absence of a feeding lantern. The group includes the well known heart urchins, as well as some less familiar and extinct ...
** Order
Holasteroida
Holasteroida is an order of irregular sea urchins.
Characteristics
These irregular sea urchins are characterized by a particularly marked bilateral symmetry, including for the apical system, which is highly elongated. In some contemporary ab ...
** Order
Spatangoida
The heart urchins or Spatangoida are an order of sea urchins.
Their body is a somewhat elongated oval in form, and is distinguished by the mouth being placed towards one end of the animal, and the anus towards the other. As a result, heart urc ...
(heart urchins)
Image:Aspidodiadema arcitum.jpg, '' Aspidodiadema hawaiiense'', an Aspidodiadematoida
Image:Diadema antillarum Flower Garden Banks.jpg, ''Diadema antillarum
''Diadema antillarum'', also known as the lime urchin, black sea urchin, or the long-spined sea urchin, is a species of sea urchin in the family Diadematidae.
This sea urchin is characterized by its exceptionally long black spines.
It is the ...
'', a Diadematoida
Image:Caenopedina hawaiiensis.jpg, '' Caenopedina hawaiiensis'', a Pedinoida
Pedinoida is an order of sea urchins, containing the single living genus '' Caenopedina''. The group was much more diverse during the Mesozoic, and represents the oldest surviving order of euechinoid sea urchins.
They are distinguished from ...
Image:Salenocidaris hastigera.png, '' Salenocidaris hastigera'', a Salenioida
The Salenioida are an order of sea urchins.
Description and characteristics
They are distinguished from other sea urchins by the presence of a large plate on the upper surface, with the anus to one side. They have very large tubercles between ...
Image:Arbacia lixula (oursin noir).JPG, ''Arbacia lixula
''Arbacia lixula'', the black sea urchin, is a species of sea urchin from Europe.
Description
It is a medium-sized sea urchin, characterized by its deep black color and its hemispherical shape. All of its spines are roughly the same size (no "s ...
'', an Arbacioida
Arbacioida are an order (biology), order of sea urchins, consisting of a single family, the Arbaciidae. They are distinguished from other sea urchins by the presence of five separate plates around the anus. Unlike their close relatives, the Salen ...
Image:Strongylocentrotus franciscanus at Telegraph Cove.jpg, ''Strongylocentrotus franciscanus
The red sea urchin (''Mesocentrotus franciscanus'') is a sea urchin found in the northeastern Pacific Ocean from Alaska to Baja California. It lives in shallow waters from the low-tide line to greater than deep, and is typically found on rocky ...
'', a Camarodonta
Image:S. variolaris.jpg, ''Stomopneustes variolaris
''Stomopneustes variolaris'', the black sea urchin or long-spined sea urchin, is a species of sea urchin, the only one in its genus ''Stomopneustes'' and only species still alive in its family Stomopneustidae. It is found throughout the tropi ...
'', a Stomopneustoida
Stomopneustoida is an order of echinoderms belonging to the class Echinoidea
Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth ...
Image:Toxic Leather Sea Urchin - Asthenosoma marisrubri.jpg, '' Asthenosoma marisrubri'', an Echinothurioida
The Echinothurioida are an order of sea urchins in the class Echinoidea. Echinothurioids are distinguished from other sea urchins by the combination of a flexible test and hollow spines. The membrane around the mouth contains only simple plates, ...
Image:Pourtalesia wandeli.png, ''Pourtalesia wandeli
''Pourtalesia'' is a genus of the family Pourtalesiidae which belongs to the irregular (bilaterally symmetrical) sea urchins. The animals measure 5–6 cm in length and live in the abyssal zone of the Atlantic, Pacific, Indopacific and ...
'', a Holasteroida
Holasteroida is an order of irregular sea urchins.
Characteristics
These irregular sea urchins are characterized by a particularly marked bilateral symmetry, including for the apical system, which is highly elongated. In some contemporary ab ...
Image:Tiny maretia heart urchin (Maretia planulata).jpg, '' Maretia planulata'', a Spatangoida
The heart urchins or Spatangoida are an order of sea urchins.
Their body is a somewhat elongated oval in form, and is distinguished by the mouth being placed towards one end of the animal, and the anus towards the other. As a result, heart urc ...
Image:Echinoneus cyclostomus.jpg, ''Echinoneus cyclostomus
''Echinoneus'' is a genus of echinoderms belonging to the family Echinoneidae.
The genus has almost cosmopolitan distribution
In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of ...
'', an Echinoneoida
Image:Clypeaster reticulatus.jpg, ''Clypeaster reticulatus
''Clypeaster reticulatus'', the reticulated sea biscuit, is a species of sea urchin in the Family Clypeasteridae. This species was first scientifically described in 1758 by Carl Linnaeus. It lives on the sandy seabed of shallow seas, semi-immers ...
'', a Clypeasteroida
Sand dollars (also known as a sea cookie or snapper biscuit in New Zealand, or pansy shell in South Africa) are species of flat, burrowing sea urchins belonging to the order Clypeasteroida. Some species within the order, not quite as flat, are k ...
Image:Echinolampas depressa.png, '' Echinolampas depressa'', an Echinolampadoida
Image:Eucidaris metularia à la Réunion.jpg, ''Eucidaris metularia
''Eucidaris metularia'', the ten-lined urchin, is a species of sea urchins in the family Cidaridae. It is found in shallow parts of the Indo-Pacific Ocean and is characterised by its sparse covering of banded, flat-tipped spines.
Description
...
'', a Cidaroida
Cidaroida is an order of primitive sea urchins, the only living order of the subclass Perischoechinoidea. All other orders of this subclass, which were even more primitive than the living forms, became extinct during the Mesozoic.
Description
...
Class Holothuroidea (
Sea cucumber
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 holothuria ...
s)
** Order
Apodida
Apodida is an order of littoral to deep-sea, largely infaunal holothurians, sea cucumbers. This order comprises three families, 32 genera and about 270 known species, called apodids, "without feet".
Characteristics
These sea cucumbers are vagile ...
** Order
Dendrochirotida
Dendrochirotida are an order of sea cucumbers. Members of this order have branched tentacles and are suspension feeders. Examples include '' Thyonella'' and '' Cucumaria''.
Characteristics
Holothurians in this order are characterised by ten to th ...
** Order
Elasipodida
Elasipodida is an order of sea cucumbers. They have numerous appendages, including conical papillae and leaf-like tentacles. Although many species are benthic, a number are pelagic, and may have their appendages modified to form sails or fins. ...
** Order
Holothuriida
Holothuriida is an order of sea cucumbers. Taxa within the order Holothuriida were previously classified in the order Aspidochirotida, which was determined to be polyphyletic in 2017. Some taxa were also reclassified into the clades Synallactida ...
** Order
Molpadida
Molpadida is an order of sea cucumbers. The body shape is fusiform and unlike other sea cucumbers, their hind body is narrowed to form a distinct tail. Although they possess tentacles around the mouth derived from the water vascular system, they ...
** Order
Persiculida
Persiculida is an order of sea cucumbers. Taxa within the order Persiculida were previously classified in an order called Aspidochirotida, which was determined to be polyphyletic
A polyphyletic group is an assemblage of organisms or other e ...
** Order
Synallactida
Synallactida is a rankless clade of sea cucumbers, but is referred to as an order. Taxa within Synallactida were previously classified in an order called Aspidochirotida, which was determined to be polyphyletic in 2017.
List of families
Syn ...
{{clr
Image:Euapta godeffroyi1.jpg, ''Euapta godeffroyi
''Euapta godeffroyi'', the sticky snake sea cucumber, is a 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 ...
'' (Apodida
Apodida is an order of littoral to deep-sea, largely infaunal holothurians, sea cucumbers. This order comprises three families, 32 genera and about 270 known species, called apodids, "without feet".
Characteristics
These sea cucumbers are vagile ...
)
Image:Cercodemas anceps Red box sea cucumber PC260152.JPG, '' Cercodemas anceps'' (Dendrochirotida
Dendrochirotida are an order of sea cucumbers. Members of this order have branched tentacles and are suspension feeders. Examples include '' Thyonella'' and '' Cucumaria''.
Characteristics
Holothurians in this order are characterised by ten to th ...
)
Image:Scotoplanes globosa and crab.jpg, ''Scotoplanes globosa
''Scotoplanes globosa,'' commonly known as the sea pig, is a species of sea cucumber that lives in the deep sea. It was first described by Hjalmar Théel, a Swedish scientist. ''Scotoplanes globosa'', along with numerous other sea cucumbers wer ...
'' (Elasipodida
Elasipodida is an order of sea cucumbers. They have numerous appendages, including conical papillae and leaf-like tentacles. Although many species are benthic, a number are pelagic, and may have their appendages modified to form sails or fins. ...
)
Image:Holothuria cinerascens Réunion.jpg, '' Holothuria cinerascens'' (Holothuriida
Holothuriida is an order of sea cucumbers. Taxa within the order Holothuriida were previously classified in the order Aspidochirotida, which was determined to be polyphyletic in 2017. Some taxa were also reclassified into the clades Synallactida ...
)
Image:See-through sea cucumber (Paracaudina australis).jpg, '' Paracaudina australis'' (Molpadida
Molpadida is an order of sea cucumbers. The body shape is fusiform and unlike other sea cucumbers, their hind body is narrowed to form a distinct tail. Although they possess tentacles around the mouth derived from the water vascular system, they ...
)
Image:Hansenothuria benti.png, '' Hansenothuria benti'' (Persiculida
Persiculida is an order of sea cucumbers. Taxa within the order Persiculida were previously classified in an order called Aspidochirotida, which was determined to be polyphyletic
A polyphyletic group is an assemblage of organisms or other e ...
)
Image:Stichopus herrmanni (Mayotte).jpg, '' Stichopus herrmanni'' (Synallactida
Synallactida is a rankless clade of sea cucumbers, but is referred to as an order. Taxa within Synallactida were previously classified in an order called Aspidochirotida, which was determined to be polyphyletic in 2017.
List of families
Syn ...
)
Class
Ophiocistioidea
The Ophiocistioidea is a class of extinct echinoderms from the Palaeozoic and early Mesozoic.
Ophiocistioids had a flattened dome-shaped body encased in a solid test of calcareous plates, similar to that of a modern sea urchin. The mouth was at ...
†
No orders recognized: class is divided up into four
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 ...
,
Eucladiidae,
Sollasiniidae,
Volchoviidae, and
Rhenosquamidae. The inclusion of Rhenosquamidae within Ophiocistioidea is doubtful, as the organs identified in fossils of ''
Rhenosquamus'' as the characteristic "scaly podia" otherwise diagnostic of ophiocistioids may not, in fact, be such structures.
Class
Helicoplacoidea
Helicoplacoidea is an extinct class within the Echinodermata. All known taxa were discovered in sediments dating back to the Cambrian. †
No known orders, 2 known species, ''Helicoplacus curtisi'' and ''H. guthi''
Subphylum
Blastozoa
Blastozoa is a subphylum of extinct animals belonging to Phylum Echinodermata. This subphylum is characterized by the presence of specialized respiratory structures and brachiole plates used for feeding. This subphylum ranged from the Cambrian to ...
Class
Blastoidea
Blastoids (class Blastoidea) are an extinct type of stemmed echinoderm, often referred to as sea buds. They first appear, along with many other echinoderm classes, in the Ordovician period, and reached their greatest diversity in the Mississi ...
†
* Ordre
Coronata †
* Order
Fissiculata †
* Order
Spiraculata
Spiraculata is an order of Blastoids. These blastoids are characterized by indirect entrance to the hydrospires through canals by way of pores.
Genera
*'' Acentrotremites''
*'' Ambolostoma''
*'' Arcuoblastus''
*'' Auloblastus''
*'' Belocrinus'' ...
†
* basal ''
Macurdablastus'' †
Class
Eocrinoidea
The Eocrinoidea are an extinct class of echinoderms that lived between the Early Cambrian and Late Silurian periods. They are the earliest known group of stalked, arm-bearing echinoderms, and were the most common echinoderms during the Cambrian. ...
†
* Order
Ascocystida †
* Order
Gogiida †
* Order
Imbricata
This list of Latin and Greek words commonly used in systematic names is intended to help those unfamiliar with classical languages to understand and remember the scientific names of organisms. The binomial nomenclature used for animals and plants i ...
†
* Order
Trachelocrinida †
Subphylum
Homostelea
Cincta is an extinct class of echinoderms that lived only in the Middle Cambrian epoch. Homostelea is a junior synonym. The classification of cinctans is controversial, but they are probably part of the echinoderm stem group.
Cinctans were sessi ...
/
Homalozoa
Homalozoa is an obsolete extinct subphylum of Paleozoic era echinoderms, prehistoric marine invertebrates. They are also referred to as carpoids.
Description
The Homalozoa lacked the typical pentamer body form of other echinoderms, but all were ...
†
Class
Ctenocystoidea
Ctenocystoidea is an extinct clade of echinoderms, which lived during the Cambrian and Ordovician periods. Unlike other echinoderms, ctenocystoids had bilateral symmetry, or were only very slightly asymmetrical. They are believed to be one of ...
†
** order
Ctenocystida †
Class Soluta †
Class
Cincta
Cincta is an extinct class of echinoderms that lived only in the Middle Cambrian epoch. Homostelea is a junior synonym. The classification of cinctans is controversial, but they are probably part of the echinoderm stem group.
Cinctans were sessi ...
†
Class
Stylophora
The stylophorans are an extinct, possibly polyphyletic group allied to the Paleozoic Era echinoderms, comprising the prehistoric cornutes and mitrates. It is synonymous with the subphylum Calcichordata. Their unusual appearances have led to a va ...
†
** order
Cornuta
Cornuta is an extinct order of echinoderms. Along with the mitrates, they form one half of the Stylophora
The stylophorans are an extinct, possibly polyphyletic group allied to the Paleozoic Era echinoderms, comprising the prehistoric co ...
†
** order
Mitrata †
References
List
Orders
Order, ORDER or Orders may refer to:
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
* Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...