Editing Centrohelid (section)

== Taxonomy ==
=== History ===
The evolutionary position of the centrohelids is not clear.  Structural comparisons with other groups are difficult, in part because no [[flagellum|flagella]] occur among centrohelids, and genetic studies have been more or less inconclusive.  Cavalier-Smith has suggested they may be related to the [[Rhizaria]],<ref name="pmid12664159">{{cite journal |vauthors=Cavalier-Smith T, Chao EE |title=Molecular phylogeny of centrohelid heliozoa, a novel lineage of bikont eukaryotes that arose by ciliary loss |journal=J. Mol. Evol. |volume=56 |issue=4 |pages=387–396 |date=April 2003 |pmid=12664159 |doi=10.1007/s00239-002-2409-y|bibcode=2003JMolE..56..387C |s2cid=8007933 }}</ref> but for the most part they are left with uncertain relations to other groups. A 2009 paper suggests that they may be related to the [[Cryptomonad|cryptophytes]] and [[haptophyte]]s (see [[Cryptomonads-haptophytes assemblage]]).<ref>{{Cite journal |author=Burki, F |author2=Inagaki, Y |author3=Bråte, J |author4=Archibald, J. |author5=Keeling, P. |author6=Cavalier-Smith, T |author7=Sakaguchi, M |author8=Hashimoto, T |author9=Horak, A |author10=Kumar, S |author11=Klaveness, D |author11-link=Dag Klaveness (limnologist) |author12=Jakobsen, K.S |author13=Pawlowski, J |author14=Shalchian-Tabrizi, K |year=2009 |title=Large-scale phylogenomic analyses reveal that two enigmatic protist lineages, Telonemia and Centroheliozoa, are related to photosynthetic chromalveolates |journal=Genome Biology and Evolution |volume=1 |pages=231–238 |doi=10.1093/gbe/evp022 |pmc=2817417 |pmid=20333193 }}</ref> They are currently classified as [[Hacrobia]], under the [[Plants+HC clade]], although some research studies have found evidence against the monophyly of this group.<ref name=ZhaoBurkBratKeel12>{{Cite journal |last1=Zhao |first1=Sen |last2=Burki |first2=Fabien |last3=Bråte |first3=Jon |last4=Keeling |first4=Patrick J. |last5=Klaveness |first5=Dag |last6=Shalchian-Tabrizi |first6=Kamran |year=2012 |title=Collodictyon—An Ancient Lineage in the Tree of Eukaryotes |journal=Molecular Biology and Evolution |doi=10.1093/molbev/mss001 |pmid=22319147 |pmc=3351787 |volume=29 |issue=6 |pages=1557–68}}</ref>
Centrohelids were previously divided into two orders with contrasting scale morphology and ultrastructure: [[Pterocystida]] and [[Acanthocystida]].<ref name="CavalierSmith">{{cite journal|last=Cavalier-Smith|first=Thomas|author2=Chao, Ema E.|year=2012|title=Oxnerella micra sp. n. (Oxnerellidae fam. n.), a Tiny Naked Centrohelid, and the Diversity and Evolution of Heliozoa|journal=Protist|volume=163|issue=4|pages=574–601|doi=10.1016/j.protis.2011.12.005|pmid=22317961}}<!--|access-date=2013-04-13 --></ref> Posterior molecular studies of 2018 have rearranged the classification of centrohelids into two taxa: Pterocystida and [[Panacanthocystida]], which includes both Acanthocystida and the genus ''[[Yogsothoth (protist)|Yogsothoth]]''.<ref name="Yogsothothidae"/><ref name="Adl 2019" />
=== Classification ===
The modern classification of centrohelids, as of 2019:<ref name="Yogsothothidae"/><ref name="Adl 2019" />
* '''Centroplasthelida''' {{au|Febvre‐Chevalier & Febvre 1984}} [=Centrohelea {{au|Kühn 1926 sensu Cavalier‐Smith in Yabuki et al. 2012}}; Centroheliozoa {{au|Dürrschmidt & Patterson 1987}}]
** [[Pterocystida]] {{au|Cavalier‐Smith and von der Heyden 2007, emend. Shɨshkin and Zlatogursky 2018}}
*** [[Raphidista]] {{au|Shɨshkin & Zlatogursky 2018}}
**** [[Choanocystidae]] <small>Cavalier-Smith & von der Heyden 2007</small>
***** ''[[Choanocystis]]'' <small>Penard 1904 non Cognetti 1918</small>
**** [[Raphidiophryidae]] <small>Mikrjukov 1996 emend. Cavalier-Smith & von der Heyden 2007</small>
***** ''[[Raphidiophrys]]'' <small>Archer 1867</small> [''Raphidiaphrys'' (sic) Greeff 1869]
*** [[Pterista]] {{au|Shɨshkin & Zlatogursky 2018}}
**** [[Oxnerellidae]] <small>Cavalier-Smith & Chao 2012</small>
***** ''[[Oxnerella]]'' <small>Dobell 1917</small>
**** [[Pterocystidae]] <small>Cavalier-Smith & von der Heyden 2007</small>
***** ''[[Chlamydaster]]'' <small>Rainer 1968</small>
***** ''[[Pseudoraphidocystis]]'' <small>Mikrjukov 1997</small> [''Pseudoraphidiocystis'' (sic)]
***** ''[[Pseudoraphidiophrys]]'' <small>Mikrjukov 1997</small>
***** ''[[Pterocystis]]'' <small>Siemensma & Roijackers 1988 non Lohmann 1904</small>
***** ''[[Raineriophrys]]'' <small>Mikrjukov 2001</small> [''Rainierophrys'' (sic); ''[[Raineria]]'' <small>Mikrjukov 1999 non Osswald 1928 non de Notaris 1838</small>; ''[[Echinocystis]]'' <small>Mikrjukov1997 non Haeckel 1896 non Bhatia & Chatterjee 1925 non Torrey & Gray 1840 non Gregory 1897</small>]
**** [[Heterophryidae]] <small>Poche 1913</small>
***** ''[[Heterophrys]]'' <small>Archer 1869</small>
***** ''[[Parasphaerastrum]]'' <small>Mikrjukov 1996</small>
***** ''[[Sphaerastrum]]'' <small>Greeff 1873</small>
** [[Panacanthocystida]] {{au|Shɨshkin & Zlatogursky 2018}}
*** [[Chthonida]] {{au|Shɨshkin & Zlatogursky 2018}}
**** [[Yogsothothina]] {{au|Shɨshkin & Zlatogursky 2018}}
***** [[Yogsothothidae]] {{au|Shɨshkin & Zlatogursky 2018}}
****** ''[[Yogsothoth (protist)|Yogsothoth]]'' {{au|Shɨshkin & Zlatogursky 2018}}
*** [[Acanthocystida]] <small>Cavalier-Smith 2011</small>
**** [[Marophryina]] <small>Cavalier-Smith 2011</small>
***** [[Marophryidae]] <small>Cavalier-Smith & von der Heyden 2007</small>
****** ''[[Marophrys]]'' {{au|Cavalier-Smith & von der Heyden 2007}}
**** [[Chalarothoracina]] <small>Hertwig & Lesser 1874 stat n. Cavalier-Smith 2011</small>
***** [[Raphidocystidae]] {{au|Zlatogursky in Zlatogursky et al., 2018}}
****** ''[[Raphidocystis]]'' <small>Penard 1904</small> [''Raphidiocystis'' (sic) Doflein 1928 ; ''Rhaphidocystis'' (sic)]
***** [[Acanthocystidae]] <small>Claus 1874 emend. Cavalier-Smith & von der Heyden 2007</small>
****** ''[[Acanthocystis]]'' <small>Carter 1863 non Kuehner 1926 non Bather 1889 non Haeckel 1896 nomen nudum</small>
** Incertae sedis Centroplasthelida:
*** ''[[Parasphaerastrum]]'' <small>Mikrjukov 1996</small>
*** ''[[Heteroraphidiophrys]]'' <small>Mikrjukov & Patterson 2000</small>{{efn|''Heteroraphidiophrys'', mentioned by Mikrjukov in 2002, was never formally introduced and needs to be avoided; the organism designated needs to be re‐isolated, carefully studied and provided with formal description.<ref name="Adl 2019" />}}
*** [[Spiculophryidae]] {{au|Shɨshkin & Zlatogursky 2018}}
**** ''[[Spiculophrys]]'' <small>Zlatogursky 2015</small>