Editing Ostracod (section)

{{Short description|Class of crustaceans}}
{{Automatic taxobox
| fossil_range = {{fossil range|Ordovician|Recent}}<ref>{{cite journal |last1=Williams |first1=Mark |last2=Siveter |first2=David J. |last3=Salas |first3=María José |last4=Vannier |first4=Jean |last5=Popov |first5=Leonid E. |last6=Ghobadi Pour |first6=Mansoureh |title=The earliest ostracods: the geological evidence |journal=Senckenbergiana Lethaea |date=June 2008 |volume=88 |issue=1 |pages=11–21 |doi=10.1007/BF03043974 }}</ref>
| image = Ostracod.JPG
| image_alt = 
| image_caption = 
| taxon = Ostracoda
| authority = [[Pierre André Latreille|Latreille]], 1802
| synonyms = 
| synonyms_ref = 
| subdivision_ranks = Subclasses and orders
| subdivision = 
*[[Myodocopa]] <small> [[Georg Ossian Sars|Sars]], 1866</small>
**[[Myodocopida]] <small>Sars, 1866</small>
**[[Halocyprida]] <small>[[James Dwight Dana|Dana]], 1853</small>
*[[Podocopa]] <small> Sars, 1866</small>
**[[Palaeocopida]] <small>Henningsmoen, 1953</small>
**[[Platycopida]] <small>Sars, 1866</small>
**[[Podocopida]] <small>Sars, 1866</small>
}}

'''Ostracods''', or ostracodes, are a [[Class (biology)|class]] of the [[crustacean|Crustacea]] (class '''Ostracoda'''), sometimes known as '''seed shrimp'''. Some 33,000 species (only 13,000 of which are [[extant taxon|extant]]) have been identified,<ref name=":0">'''Brandão, S.N.; Antonietto, L.S; Nery, D.G.; Santos, S.G.; Karanovic, I. (2023). World Ostracoda Database. Accessed at https://www.marinespecies.org/ostracoda  on 2023-09-12. {{doi|10.14284/364}}'''</ref> grouped into 7 valid orders.<ref name=":0" /> They are small crustaceans, typically around {{convert|1|mm|in|abbr=on|sigfig=1}} in size, but varying from {{convert|0.2|to|32|mm|in|abbr=on|sigfig=2}}, the latter in the case of the marine ''[[Gigantocypris]].'' The largest known freshwater species is ''[[Megalocypris princeps]]'', which reach 8&nbsp;mm in length.<ref>[https://books.google.com/books?id=5Q1bDwAAQBAJ&dq=South+Africa+pride+largest+living+Megalocypris+princeps&pg=PT837 Freshwater Life: A field guide to the plants and animals of southern Africa]</ref><ref>[https://books.google.com/books?id=ulvmCQAAQBAJ&dq=Ostracods+adult+interstitial+forms+0.2+mm&pg=PA427 The Triassic-Jurassic Terrestrial Transition: 37]</ref> In most cases, their bodies are flattened from side to side and protected by a [[bivalve]]-like valve or "shell" made of [[chitin]], and often calcium carbonate. The family [[Entocytheridae]] and many planktonic forms do not have calcium carbonate.<ref>{{Cite thesis |last=Jöst |first=Anna B. |title=Ecological Evaluation of Ostracode (Crustacea) Occurrence in the City of Munich & Phylogenetic Relationships between Ostracode Species and Populations from Bavaria |date=January 2012 |degree=master |publisher=[[Ludwig Maximilian University of Munich]] |url=https://www.researchgate.net/publication/331485946}}</ref><ref>{{cite book |doi=10.1093/oso/9780195365764.003.0010 |chapter=Ostracoda |title=Evolution and Phylogeny of Pancrustacea |date=2022 |last1=Schram |first1=Frederick R. |last2=Koenemann |first2=Stefan |pages=119–140 |isbn=978-0-19-536576-4 }}</ref> The hinge of the two valves is in the upper (dorsal) region of the body. Ostracods are grouped together based on shell and soft part morphology, and molecular studies have not unequivocally supported the group's [[monophyly]].<ref name="oakley2013">{{cite journal |last1=Oakley |first1=Todd H. |last2=Wolfe |first2=Joanna M. |last3=Lindgren |first3=Annie R. |last4=Zaharoff |first4=Alexander K. |title=Phylotranscriptomics to Bring the Understudied into the Fold: Monophyletic Ostracoda, Fossil Placement, and Pancrustacean Phylogeny |journal=Molecular Biology and Evolution |date=January 2013 |volume=30 |issue=1 |pages=215–233 |doi=10.1093/molbev/mss216 |pmid=22977117 }}</ref> They have a wide range of diets, and the class includes carnivores, herbivores, scavengers and filter feeders, but most ostracods are [[Detritivores|deposit feeders]].