Editing Sea cucumber (section)

{{short description|Class of echinoderms}}
{{pp|small=yes}}
{{Automatic taxobox
| fossil_range = {{fossil range|Darriwilian|present|Middle Ordovician-present}}
| image = Actinopyga echinites1.jpg
| image_caption = A sea cucumber (''[[Actinopyga echinites]]''), displaying its feeding tentacles and [[tube feet]]
| taxon = Holothuroidea
| authority = [[Henri Marie Ducrotay de Blainville|Blainville]], 1834
| subdivision_ranks = Orders
| subdivision = 
* [[Apodida]] <small>Brandt, 1835</small>
* †[[Arthrochirotida]] <small>Seilacher, 1961</small>
* [[Dendrochirotida]] <small>Grube, 1840</small>
* [[Elasipodida]] <small>Théel, 1882</small>
* [[Holothuriida]] <small>Miller, Kerr, Paulay, Reich, Wilson, Carvajal & Rouse, 2017</small>
* [[Molpadida]] <small>Haeckel, 1896</small>
* [[Persiculida]] <small>Miller, Kerr, Paulay, Reich, Wilson, Carvajal & Rouse, 2017</small>
* [[Synallactida]] <small>Miller, Kerr, Paulay, Reich, Wilson, Carvajal & Rouse, 2017</small>
}}
[[File:Thelenota ananas.jpg|thumb|''[[Thelenota ananas]]'', a giant sea cucumber from the [[Indo-Pacific]] tropics]]

'''Sea cucumbers''' are [[echinoderm]]s from the [[class (biology)|class]] '''Holothuroidea''' ({{IPAc-en|ˌ|h|ɒ|l|ə|ˌ|θj|ʊəˈr|ɔɪ|d|i|ə|,_|ˌ|h|oʊ|l|ə|-}} {{respell|HOL|ə|thyuu|ROY|dee|ə|,_|HOH|lə|-}}). They are [[benthic]] [[marine animal]]s found on the [[sea floor]] worldwide, and the number of known '''holothuroid''' species worldwide is about 1,786,<ref>{{cite web |url=http://www.marinespecies.org/aphia.php?p=browser&id=148744&expand=true#ct |title=Holothuroidea |last=Paulay |first=G. |year=2014 |work=[[World Register of Marine Species]] |access-date=2 March 2014}}</ref> with the greatest number being in the [[Asia–Pacific]] region.<ref name=PLoSone>{{cite journal |author1=Du, H. |author2=Bao, Z. |author3=Hou, R. |author4=Wang, S. |author5=Su, H. |year=2012 |title=Transcriptome Sequencing and Characterization for the Sea Cucumber ''Apostichopus japonicus'' (Selenka, 1867) |journal=[[PLOS One]] |volume=7 |issue=3 |pages=e33311 |doi=10.1371/journal.pone.0033311 |pmid= 22428017 |pmc=3299772 |display-authors=etal |bibcode=2012PLoSO...733311D |doi-access=free}}</ref> Sea cucumbers serve a useful role in the [[marine ecosystem]] as [[detritivore]]s who help recycle nutrients, breaking down [[detritus]] and other [[organic matter]], after which microbes can continue the [[decomposition]] process.<ref name=PLoSone/>

Sea cucumbers have a leathery [[skin]] and an elongated body containing a single, branched [[gonad]], are named for their overall resemblance to the fruit of the [[cucumber]] plant. Like all [[echinoderm]]s, sea cucumbers have a calcified [[dermal]] [[endoskeleton]], which is usually reduced to isolated microscopic [[ossicle (echinoderm)|ossicles]] (or sclerietes) joined by [[connective tissue]]. In some species these can sometimes be enlarged to flattened plates, forming an armoured [[cuticle]]. In some abyssal or [[pelagic]] species such as ''[[Pelagothuria natatrix]]'' (order [[Elasipodida]], family [[Pelagothuriidae]]), the skeleton is absent and there is no [[calcareous]] ring.<ref>{{cite journal |first=Mike |last=Reich |url=http://www.geobiologie.uni-goettingen.de/people/mreich/pdf/PDFs/POST_Dijon_Seegurken1.pdf |archive-url=https://web.archive.org/web/20090225190556/http://www.geobiologie.uni-goettingen.de/people/mreich/pdf/PDFs/POST_Dijon_Seegurken1.pdf |url-status=dead |archive-date=February 25, 2009 |title=Cambrian holothurians? – The early fossil record and evolution of Holothuroidea |editor=Lefebvre, B. |editor2=David, B. |editor3=Nardin, E. |editor4=Poty, E. |journal= Journées Georges Ubaghs |date=30–31 January 2006 |pages=36–37}}</ref>

Many species of sea cucumbers are [[sea cucumbers as food|foraged as food]] by [[human]]s, and some species are cultivated in [[aquaculture]] systems. They are considered a [[delicacy]] [[seafood]], especially in [[Asian cuisines]], and the harvested product is variously referred to as ''[[trepanging|trepang]]'', ''namako'', ''[[wikt:bêche-de-mer|bêche-de-mer]]'', or ''balate''.