Editing Rotifer (section)

{{Short description|Phylum of pseudocoelomate invertebrates}}
{{Use dmy dates|date=May 2020}}
{{Automatic taxobox
| name = Rotifera
| fossil_range = {{Fossil range|earliest=Devonian|Middle Jurassic|Recent}} Possible Devonian and Permian records
| image = Mikrofoto.de-Raedertier-14.jpg
| image_caption = Bdelloid rotifer ([[Bdelloidea]])
| image2 = Pulchritia dorsicornuta - ZooKeys-342-001-g001.jpg
| image2_caption = ''Pulchritia dorsicornuta'' ([[Monogononta]])
| display_parents = 5
| taxon = Rotifera
| authority = [[Georges Cuvier|Cuvier]], 1798
| subdivision_ranks = Classes and other subgroups
| subdivision = * [[Eurotatoria]]
** [[Bdelloidea]]
** [[Monogononta]]
* [[Pararotatoria]]
** [[Seisonidae]]
*[[Acanthocephala]]{{small|(cladistically included)}}

and [[#Taxonomy and naming|See text]].
}}

The '''rotifers''' ({{IPAc-en|ˈ|r|oʊ|t|ᵻ|f|ər|z}}, from [[Latin]] {{lang|la|[[wikt:rota#Latin|rota]]}} 'wheel' and {{lang|la|[[wikt:-fer#Latin|-fer]]}} 'bearing'), sometimes called '''wheel animals''' or '''wheel animalcules''',<ref name="Howey">{{cite web |last=Howey |first=Richard L. |year=1999 |title=Welcome to the Wonderfully Weird World of Rotifers |url=http://www.microscopy-uk.org.uk/mag/indexmag.html?http://www.microscopy-uk.org.uk/mag/artnov99/rotih.html |access-date=2010-02-19 |publisher=Micscape Magazine |language=en-US}}</ref> make up a [[phylum]] ('''Rotifera''' {{IPAc-en|r|oʊ|'|t|I|f|ər|@}}) of microscopic and near-microscopic [[Coelom#Pseudocoelomates|pseudocoelomate]] [[animal]]s.

They were first described by [[John Harris (writer)|Rev. John Harris]] in 1696, and other forms were described by [[Antonie van Leeuwenhoek]] in 1703.<ref name="cambridge1896">{{cite book | title = The Cambridge Natural History |author1=Harmer, Sidney Frederic  |author2=Shipley, Arthur Everett  |name-list-style=amp | year = 1896 | publisher = The Macmillan company | url = https://archive.org/details/cambridgenatura00shipgoog | quote = john harris rotifer. | pages = [https://archive.org/details/cambridgenatura00shipgoog/page/n9 197] | access-date = 2008-07-25}}</ref> Most rotifers are around {{cvt|0.1–0.5|mm}} long (although their size can range from {{cvt|50|μm}} to over {{cvt|2|mm}}),<ref name="Howey" /> and are common in [[freshwater]] environments throughout the world with a few [[Seawater|saltwater]] species.

Some rotifers are free swimming and truly [[plankton]]ic, others move by inchworming along a substrate, and some are [[Sessility (zoology)|sessile]], living inside tubes or gelatinous [[holdfast (biology)|holdfast]]s that are attached to a substrate. About 25 species are colonial (e.g., ''[[Sinantherina semibullata]]''), either sessile or planktonic. Rotifers are an important part of the freshwater [[zooplankton]], being a major foodsource and with many species also contributing to the decomposition of soil organic matter.<ref>{{cite web|url=http://www.freshwaterlife.org/servlet/CDSServlet?status=ND01MDU3JmN0bl9pbmZvX3ZpZXdfc2l6ZT1jdG5faW5mb192aWV3X2Z1bGwmNj1lbiYzMz0qJjM3PWtvcw~~|archive-url=https://archive.today/20120801144708/http://www.freshwaterlife.org/servlet/CDSServlet?status=ND01MDU3JmN0bl9pbmZvX3ZpZXdfc2l6ZT1jdG5faW5mb192aWV3X2Z1bGwmNj1lbiYzMz0qJjM3PWtvcw~~|url-status=dead|archive-date=2012-08-01|title=Rotifers|work=Freshwater Life |access-date=2010-02-19}}</ref> Genetic evidence indicates that the parasitic [[Acanthocephala|acanthocephalans]] are a highly specialised group of rotifers.<ref name=":0">{{Cite journal |last=Luo |first=Cihang |last2=Parry |first2=Luke A. |last3=Boudinot |first3=Brendon E. |last4=Wang |first4=Shengyu |last5=Jarzembowski |first5=Edmund A. |last6=Zhang |first6=Haichun |last7=Wang |first7=Bo |date=2025-04-09 |title=A Jurassic acanthocephalan illuminates the origin of thorny-headed worms |url=https://www.nature.com/articles/s41586-025-08830-5 |journal=Nature |language=en |doi=10.1038/s41586-025-08830-5 |issn=0028-0836|url-access=subscription }}</ref>

Most species of the rotifers are [[Cosmopolitan distribution|cosmopolitan]], but there are also some [[Endemism|endemic]] species, like ''[[Cephalodella vittata]]'' to [[Lake Baikal]].<ref>Hendrik Segers (2007). Annotated checklist of the rotifers (Phylum Rotifera), with notes on nomenclature, taxonomy</ref> Recent [[DNA barcoding|barcoding]] evidence, however, suggests that some 'cosmopolitan' species, such as ''[[Brachionus plicatilis]]'', ''[[Brachionus calyciflorus|B. calyciflorus]]'', ''[[Lecane bulla]]'', among others, are actually [[species complex]]es.<ref>{{Cite journal|title = Speciation in ancient cryptic species complexes: evidence from the molecular phylogeny of ''Brachionus plicatilis'' (Rotifera)|journal = Evolution; International Journal of Organic Evolution|date = July 2002|issn = 0014-3820|pmid = 12206243|pages = 1431–1444|volume = 56|issue = 7|first1 = Africa|last1 = Gómez|first2 = Manuel|last2 = Serra|first3 = Gary R.|last3 = Carvalho|first4 = David H.|last4 = Lunt|doi=10.1111/j.0014-3820.2002.tb01455.x|doi-access = free}}</ref><ref>Dec 2011 4th Internat. Barcode of Life conference, University of Adelaide</ref> In some recent treatments, rotifers are placed with [[acanthocephalan]]s in a larger [[clade]] called '''Syndermata'''.

In June 2021, biologists reported the restoration of [[Bdelloidea|bdelloid rotifers]] after being frozen for 24,000 years in the [[Siberia]]n [[permafrost]].<ref name="NYT-20210607">{{cite news |last=Renault |first=Marion |title=This Tiny Creature Survived 24,000 Years Frozen in Siberian Permafrost - The microscopic animals were frozen when woolly mammoths still roamed the planet, but were restored as though no time had passed. |url=https://www.nytimes.com/2021/06/07/science/frozen-rotifers-siberia.html |date=7 June 2021 |work=[[the New York Times]] |accessdate=8 June 2021 }}</ref><ref>{{cite journal |last1=Shmakova |first1=Lyubov |last2=Malavin |first2=Stas |last3=Iakovenko |first3=Nataliia |last4=Vishnivetskaya |first4=Tatiana |last5=Shain |first5=Daniel |last6=Plewka |first6=Michael |last7=Rivkina |first7=Elizaveta |title=A living bdelloid rotifer from 24,000-year-old Arctic permafrost |journal=Current Biology |date=June 2021 |volume=31 |issue=11 |pages=R712–R713 |doi=10.1016/j.cub.2021.04.077 |pmid=34102116 |s2cid=235365588 |doi-access=free |bibcode=2021CBio...31.R712S }}</ref> The earliest record of the rotifer clade is of an acanthocephalan from the [[Middle Jurassic]] of China.<ref name=":0" /> Earlier purported fossils of rotifers have been suggested in Devonian<ref>{{cite web|url=http://chertnews.de/attack.html|title=Spoilt attack in the Lower Devonian}}</ref> and Permian<ref>{{cite journal|url=https://www.researchgate.net/publication/236255968|title=The Oldest Bdelloid Rotifera from Early Permian sediments of Chamba Valley: A New Discovery|journal=International Journal of Geology, Earth and Environmental Science}}</ref> fossil beds.