View source for Stramenopile

{{short description|Clade of eukaryotes}}
{{good article}}
{{Automatic taxobox
| image_alt = 
| fossil_range = Late [[Mesoproterozoic]]-present, {{long fossil range|1025|0|earliest=1077|ref=<ref name="Yoon 2009">{{cite book |last1=H.S. Yoon |last2=R.A. Andersen |last3=S.M. Boo |last4=D. Bhattacharya |chapter=Stramenopiles|title=Encyclopedia of Microbiology |edition=Third |date=17 February 2009 |pages=721–731 |doi=10.1016/B978-012373944-5.00253-4 |isbn=978-0-12-373944-5 |chapter-url=https://www.sciencedirect.com/science/article/abs/pii/B9780123739445002534 |access-date=2 March 2024|chapter-url-access=subscription }}</ref>}}
| image = <imagemap>
File:Stramenopiles diversity.png|260px

rect   0 0 1100 875 [[Kelp]]
rect   1100 0 2200 875 [[Oomycete]]
rect   2200 0 3300 875 [[Bicosoecid]]

rect   0 875 1100 1750 [[Diatom]]
rect   1100 875 2200 1750 [[Labyrinthulomycetes]]
rect   2200 875 3300 1750 [[Opaline]]

rect   0 1750 1100 2625 [[Yellow-green algae]]
rect   1100 1750 2200 2625 [[Golden algae]]
rect   2200 1750 3300 2625 [[Silicoflagellate]]

</imagemap>
| image_caption = Diversity of stramenopiles
| taxon = Stramenopiles
| authority = Patterson, 1989<ref name="Patterson-1989">{{cite book |last=Patterson |first=D.J. |chapter=Stramenopiles: Chromophytes from a protistan perspective |pages=357–379 |editor-first=J.C. |editor-last=Green |editor2-first=B.S.C. |editor2-last=Leadbeater |editor3-first=W.L. |editor3-last=Diver |title=The chromophyte algae: Problems and perspectives |year=1989 |isbn=978-0-19-857713-3 |publisher=Clarendon Press |location=Oxford |url-access=registration |url=https://archive.org/details/chromophytealgae0000unse }}</ref> emend. Adl ''et al.'' 2005<ref name="Adl 2005"/><ref name="Adl 2019"/>
| subdivision_ranks = Subgroups<ref name="8phyla"/><ref name="Adl 2019"/><ref>{{cite journal|last1=Weston|first1=Elizabeth J.|last2=Eglit|first2=Yana|last3=Simpson|first3=Alastair G.B.|date=2023|title=''Kaonashia insperata'' gen. et sp. nov., a eukaryotrophic flagellate, represents a novel major lineage of heterotrophic stramenopiles|journal=Journal of Eukaryotic Microbiology|volume=71|issue=1|article-number=e13003|doi=10.1111/jeu.13003|doi-access=free|pmid=37803921}}</ref>
| subdivision_ref = 
| subdivision = *"[[Bigyra]]"
**[[Opalozoa]]
**[[Sagenista]]
*[[Gyrista]]
**[[Bigyromonada]]
**[[Ochrophyte|Ochrophyta]]
**[[Pseudofungi]]
*''[[Kaonashia]]''
*''[[Platysulcus]]''
| synonyms = * Stramenopila <small>Alexopoulos ''et al.'', 1996</small><ref name="Alexopoulos-1996">{{cite book |last1=Alexopoulos |first1=C.J. |last2=Mims |first2=C.W. |last3=Blackwell |first3=M. |title=Introductory Mycology |publisher=Wiley |edition=4th |year=1996 |isbn=978-0-471-52229-4 }}</ref>
* Straminopiles <small>Vørs, 1993</small><ref name="Vørs-1993">{{cite journal |last1=Vørs |first1=N. |year=1993 |title=Marine heterotrophic amoebae, flagellates and heliozoa from Belize (Central America) and Tenerife |journal=Journal of Eukaryotic Microbiology |volume=40 |issue=3 |pages=272–287 |doi=10.1111/j.1550-7408.1993.tb04917.x |s2cid=221852241 }}</ref><ref name="David, 2002">{{cite journal |first=J.C. |last=David |title=A preliminary catalogue of the names of fungi above the rank of order |journal=Constancea |volume=83 |pages=1–30 |year=2002 |url=http://ucjeps.berkeley.edu/constancea/83/david/ht.html}}</ref>
* Heterokonta <small>[[Cavalier-Smith]], 1986</small><ref>{{cite book |last=Cavalier-Smith |first=T. |author-link=Tom Cavalier-Smith |chapter=The kingdom Chromista, origin and systematics |editor-last=Round |editor-first=F.E. |editor2-last=Chapman |editor2-first=D.J. |title=Progress in Phycological Research |chapter-url=https://books.google.com/books?id=aTAJAQAAMAAJ |year=1999 |publisher=Elsevier |volume=4 |pages=309–347 |isbn=978-0-948737-00-8}}</ref>
* Heterokontophyta <small>van den Hoek et al., 1995</small><ref>{{cite book |last1=van den Hoek |first1=C. |last2=Mann |first2=D.G. |last3=Jahns |first3=H.M. |title=Algae An Introduction to Phycology |publisher=Cambridge University Press |year=1995 |isbn=978-0-521-30419-1 }}</ref>
* Straminipila <small>Dick, 2001</small><ref name="Dick, M. W. 2001">{{cite book |first=M.W. |last=Dick |title=Straminipilous Fungi: Systematics of the Peronosporomycetes Including Accounts of the Marine Straminipilous Protists, the Plasmodiophorids and Similar Organisms |url=https://books.google.com/books?id=xkf8CAAAQBAJ |date=2013 |publisher=Springer |isbn=978-94-015-9733-3}}</ref>
* Stramenipila <small>Dick, 2001, [[orth. var.]]</small><ref>[http://www.mycobank.org/BioloMICS.aspx?Link=T&TableKey=14682616000000067&Rec=469798&Fields=All "Stramenipila M.W. Dick (2001)"]. [[MycoBank]]. International Mycological Association.</ref>
| diversity = >100,000 species<ref name="Yoon 2009"/>
}}

The '''stramenopiles''', also called '''heterokonts''', are [[protist]]s distinguished by the presence of stiff tripartite external hairs. In most species, the hairs are attached to [[flagella]], in some they are attached to other areas of the cellular surface, and in some they have been secondarily lost (in which case relatedness to stramenopile ancestors is evident from other shared cytological features or from genetic similarity). Stramenopiles represent one of the three major clades in the [[SAR supergroup]], along with [[Alveolate|Alveolata]] and [[Rhizaria]].

Stramenopiles are [[eukaryote]]s; most are single-celled, but some are [[Multicellular organism|multicellular]] including some large seaweeds, the [[brown algae]].  The group includes a variety of algal [[protist]]s, heterotrophic flagellates, [[opaline]]s and closely related [[proteromonad]] flagellates (all [[Endosymbiont|endobionts]] in other organisms); the actinophryid [[Heliozoa]], and [[oomycete]]s. The tripartite hairs characteristic of the group have been lost in some of the included taxa – for example in most [[diatom]]s.

Many stramenopiles are unicellular [[flagellate]]s, and most others produce flagellated cells at some point in their lifecycles, for instance as [[gamete]]s or [[zoospore]]s. Most flagellated heterokonts have two flagella; the anterior flagellum has one or two rows of stiff hairs or [[mastigoneme]]s, and the posterior flagellum is without such embellishments, being smooth, usually shorter, or in a few cases not projecting from the cell.

The term 'heterokont' is used both as an adjective, indicating that a cell has two dissimilar flagella, and as the name of a taxon. The groups included in that taxon have however varied widely, creating the 'heterokont problem', now resolved by the definition of the stramenopiles.

== Nomenclature ==

The term 'stramenopile' was introduced by [[David J. Patterson|D. J. Patterson]] in 1989, defining a group that overlapped with the ambiguously defined heterokonts.<ref name="Patterson-1989"/><ref>{{cite journal |first=David J. |last=Patterson |title=The Diversity of Eukaryotes |journal=The American Naturalist |volume=154 |issue=S4 |year=1999  |pages=S96–S124 |doi=10.1086/303287 |pmid=10527921 |bibcode=1999ANat..154S..96P |s2cid=4367158 }}</ref> The name "stramenopile" has been discussed by J. C. David.<ref>{{cite journal |last=David |first=J. C. |year=2002 |title=A preliminary catalogue of the names of fungi above the rank of order |journal=Constancea |issue=83 |pages=1–30 |url=https://ucjeps.berkeley.edu/constancea/83/david/ht.html }}</ref> Patterson's term was formalized as a taxonomic name, '''Stramenopiles''', in 2005 by the International Society of Protistologists.<ref name="Adl 2005"/> It has since been the most widely accepted name for this group of organisms.<ref name="Adl 2019"/> Several alternative names have been proposed since Patterson's publication, such as Straminipila,<ref name="Dick, M. W. 2001"/> Straminopiles,<ref name="Vørs-1993"/> and Stramenopila,<ref name="Alexopoulos-1996"/> which is the valid name under the [[PhyloCode]].<ref>{{Cite web |title=RegNum {{!}} Search: Index |url=https://www.phyloregnum.org/?term=Stramenopila |access-date=20 April 2025 |website=RegNum}}</ref>

=== The heterokont problem ===

The term 'heterokont' is used as both an adjective – indicating that a cell has two dissimilar flagella – and as the name of a taxon. The taxon 'Heterokontae' was introduced in 1899 by Alexander Luther for algae that are now considered the [[Xanthophyceae]].<ref>{{cite book |last=Luther |first=Alexander F. |title=Über Chlorosaccus eine neue Gattung der Süsswasseralgen nebst einiger Bemerkungen zur Systematik verwandter Algen |language=de |trans-title=About Chlorosaccus a new genus of freshwater algae together with some comments on the systematics of related algae  |date=1899 |publisher=[[Norstedts förlag|Norstedt]] |location=Stockholm |pages=1–22}}</ref> But the same term was used for other groupings of algae. For example, in 1956, Copeland<ref>{{cite book |last=Copeland |first=H. F. |year=1956 |title=The Classification of Lower Organisms |publisher=Pacific Books |location=Palo Alto, California}}</ref> used it to include the xanthophytes (using the name Vaucheriacea), a group that included what became known as the [[chrysophyte]]s, the [[Silicoflagellata|silicoflagellates]], and the [[hyphochytrid]]s.  Copeland also included the unrelated collar flagellates (as the [[choanoflagellate]]s) in which he placed the [[bicosoecid]]s. He also included the not-closely related [[haptophyte]]s.  The consequence of associating multiple concepts to the taxon 'heterokont' is that the meaning of 'heterokont' can only be made clear by making reference to its usage: Heterokontae sensu Luther 1899; Heterokontae sensu Copeland 1956, etc. This contextual clarification is rare, such that when the taxon name is used, it is unclear how it should be understood. The term 'heterokont' has lost its usefulness in critical discussions about the identity, nature, character and relatedness of the group.<ref>{{cite journal |last=Blackwell |first=W. H. |year=2009 |title=Chromista revisited: A dilemma of overlapping putative kingdoms, and the attempted application of the botanical code of nomenclature |url=http://www.phytologia.org/uploads/2/3/4/2/23422706/912191-225blackwellchromistarevisted.pdf |journal=Phytologia |volume=91 |issue=2 }}</ref> The term 'stramenopile' sought to identify a clade (monophyletic and holophyletic lineage) using the approach developed by transformed cladists of pointing to a defining innovative characteristic or apomorphy.<ref>{{cite book |last=Patterson |first=Colin |year=1982 |chapter= Morphological characters and homology |editor1=Joysey, Kenneth A. |editor2=Friday, A. E. |title=Problems in Phylogenetic Reconstruction |series=Systematics Association Special Volume 21 |location=London |publisher=Academic Press |isbn=978-0-1239-1250-3 }}</ref>

Over time, the scope of application has changed, especially when in the 1970s ultrastructural studies revealed greater diversity among the algae with chromoplasts (chlorophylls a and c) than had previously been recognized.  At the same time, a protistological perspective was replacing the 19th century one based on the division of unicellular eukaryotes into animals and plants.  One consequence was that an array of heterotrophic organisms, many not previously considered as 'heterokonts', were seen as related to the 'core heterokonts' (those having anterior flagella with stiff hairs).  Newly recognized relatives included the parasitic [[opalinidae|opalines]], [[proteromonad]]s, and actinophryid [[Heliozoa]]. They joined other heterotrophic protists, such as [[bicosoecid]]s, [[labyrinthulid]]s, and [[oomycete]] fungi, that were included by some as heterokonts and excluded by others. Rather than continue to use a name whose meaning had changed over time and was hence ambiguous, the name 'stramenopile' was introduced to refer to the clade of protists that had tripartite stiff (usually flagellar) hairs and all their descendants. Molecular studies confirm that the genes that code for the proteins of these hairs are exclusive to stramenopiles.<ref>{{Cite journal |last1=Hee |first1=Wei Yih |last2=Blackman |first2=Leila M. |last3=Hardham |first3=Adrienne R. |doi=10.1007/s00709-018-1314-1 |title=Characterisation of Stramenopile-specific mastigoneme proteins in Phytophthora parasitica |year=2019  |journal=Protoplasma |volume=256 |issue=2 |pages=521–535 |pmid=30302550 |bibcode=2019Prpls.256..521H |s2cid=52947780 }}</ref>

== Characteristics ==

{{multiple image
|image1=Cafeteria roenbergensis FENCHEL and D J PATTERSON schematic drawing.svg
|caption1=Schematic drawing of ''[[Cafeteria roenbergensis]]'' (a heterotrophic [[bicosoecid]]), a common bacterivore in marine ecosystems: the anterior flagellum is tripartite and covered with hairs ([[mastigoneme]]s); the posterior flagellum is without hairs.
|image2=Cafeteria roenbergensis atcc50561 Protsville.jpg
|caption2=Two living ''C. roenbergensis''. Light micrograph. The cells are about 6 µm long. The anterior flagellum beats with an undulating pattern, the posterior (recurrent or smooth) flagellum usually holds the cell to the substrate.
}}

The presumed [[apomorphy]] of tripartite flagellar hairs in stramenopiles is well characterized. The basal part of the hair is flexible and inserts into the cell membrane; the second part is dominated by a long stiff tube (the 'straw' or 'stramen'); and finally the tube is tipped by many delicate hairs called [[mastigoneme]]s.<ref name="Bouck 1971">{{cite journal |last=Bouck |first=G. Benjamin |title=The structure, origin, and composition of the tubular mastigonemes of the ''Ochromonas'' flagellum |journal=Journal of Cell Biology |volume=50 |issue=2 |date=1 August 1971 |doi=10.1083/jcb.50.2.362 |pages=362–384|pmid=5123323 |pmc=2108286 }}</ref> The proteins that code for the mastigonemes appear to be exclusive to the stramenopile clade, and are present even in taxa (such as diatoms) that no longer have such hairs.<ref name="Blackman Arikawa Yamada Suzaki 2011">{{cite journal |last1=Blackman |first1=Leila M. |last2=Arikawa |first2=Mikihiko |last3=Yamada |first3=Shuhei |last4=Suzaki |first4=Toshinobu |last5=Hardham |first5=Adrienne R. |title=Identification of a Mastigoneme Protein from Phytophthora nicotianae |journal=Protist |volume=162 |issue=1 |year=2011 |doi=10.1016/j.protis.2010.01.005 |pages=100–114|pmid=20663714 }}</ref>

Most stramenopiles have two flagella near the apex.<ref name="Yoon Andersen Boo Bhattacharya 2009 pp. 721–731">{{cite book |last1=Yoon |first1=H.S. |last2=Andersen |first2=R.A. |last3=Boo |first3=S.M. |last4=Bhattacharya |first4=D. |title=Encyclopedia of Microbiology |chapter=Stramenopiles |publisher=Elsevier |year=2009 |doi=10.1016/b978-012373944-5.00253-4 |pages=721–731|isbn=978-0-12-373944-5 }}</ref> They are usually supported by four [[microtubule]] roots in a distinctive pattern. There is a transitional helix inside the flagellum where the beating [[axoneme]] with its distinctive geometric pattern of nine peripheral couplets around two central microtubules changes into the nine-triplet structure of the basal body.<ref name="Fu Nagasato Oka Cock 2014 pp. 662–675">{{cite journal |last1=Fu |first1=Gang |last2=Nagasato |first2=Chikako |last3=Oka |first3=Seiko |last4=Cock |first4=J. Mark |last5=Motomura |first5=Taizo |title=Proteomics Analysis of Heterogeneous Flagella in Brown Algae (Stramenopiles) |journal=Protist |volume=165 |issue=5 |year=2014 |doi=10.1016/j.protis.2014.07.007 |pages=662–675|pmid=25150613 |s2cid=7936118 |url=https://hal.sorbonne-universite.fr/hal-01113862/file/PROTIST.pdf }}</ref>

=== Plastids ===

Many stramenopiles have [[plastid]]s which enable them to [[photosynthesis]]e, using light to [[autotroph|make their own food]]. Those plastids are coloured off-green, orange, golden or brown because of the presence of [[chlorophyll a]], [[chlorophyll c]], and [[fucoxanthin]]. This form of plastid is called a stramenochrome or [[chromoplast]].{{efn|They are not called chloroplasts, the most common form of photosynthetic plastid. If used narrowly, a chloroplast is a plastid which contains chlorophyll B, as in [[green algae]], some [[euglenid]]s, and the [[land plants]].}}  The most significant autotrophic stramenopiles are the [[brown algae]] (wracks and many other seaweeds), and the [[diatom]]s. The latter are among the most significant primary producers in marine and freshwater ecosystems.<ref name="Leipe Wainright Gunderson Porter 1994">{{cite journal |last1=Leipe |first1=D. D. |last2=Wainright |first2=P. O. |last3=Gunderson |first3=J. H. |last4=Porter |first4=D. |last5=Patterson |first5=D. J. |last6=Valois |first6=F. |last7=Himmerich |first7=S. |last8=Sogin |first8=M. L. |display-authors=3 |title=The stramenopiles from a molecular perspective: 16S-like rRNA sequences from Labyrinthuloides minuta and Cafeteria roenbergensis |journal=Phycologia |volume=33 |issue=5 |year=1994 |doi=10.2216/i0031-8884-33-5-369.1 |pages=369–377 |bibcode=1994Phyco..33..369L }}</ref> Most molecular analyses suggest that the most basal stramenopiles lacked plastids and were accordingly colourless [[heterotroph]]s, feeding on other organisms. This implies that the stramenopiles arose as heterotrophs, diversified, and then some of them acquired chromoplasts. Some lineages (such as the [[axodine]] lineage that included the chromophytic [[pedinellid]]s, colourless ciliophryids, and colourless actinophryid heliozoa) have secondarily reverted to heterotrophy.<ref name="Leyland Leu Boussiba 2017">{{cite journal |last1=Leyland |first1=Ben |last2=Leu |first2=Stefan |last3=Boussiba |first3=Sammy |title=Are Thraustochytrids algae? |journal=Fungal Biology |volume=121 |issue=10 |year=2017 |doi=10.1016/j.funbio.2017.07.006 |pages=835–840|pmid=28889907 |bibcode=2017FunB..121..835L }}</ref><ref name="Derelle López-García Timpano Moreira 2016">{{cite journal |last1=Derelle |first1=Romain |last2=López-García |first2=Purificación |last3=Timpano |first3=Hélène |last4=Moreira |first4=David |title=A Phylogenomic Framework to Study the Diversity and Evolution of Stramenopiles (=Heterokonts) |journal=Molecular Biology and Evolution |volume=33 |issue=11 |date=10 August 2016 |doi=10.1093/molbev/msw168 |pages=2890–2898|pmid=27512113 |pmc=5482393 }}</ref>

== Ecology ==
[[file:Kelp-forest-Monterey.jpg|thumb|upright|Giant kelp, ''[[Macrocystis pyrifera]]'', an example of a multicellular stramenopile, is a large [[seaweed]], up to {{convert|45|m|ft|abbr=off|-1}} long, in the [[Phaeophyceae]], within the Gyrista.]]

Some stramenopiles are significant as autotrophs and as heterotrophs in natural ecosystems; others are parasitic. 
''[[Blastocystis]]'' is a gastrointestinal parasite of humans;<ref name="Roberts Stark Harkness Ellis 2014 p=17">{{cite journal |last1=Roberts |first1=Tamalee |last2=Stark |first2=Damien |last3=Harkness |first3=John |last4=Ellis |first4=John |title=Update on the pathogenic potential and treatment options for Blastocystis sp |journal=Gut Pathogens |volume=6 |issue=1 |year=2014 |doi=10.1186/1757-4749-6-17 |page=17|pmid=24883113 |pmc=4039988 |doi-access=free }}</ref> 
opalines and proteromonads live in the intestines of cold-blooded vertebrates and have been described as parasitic;<ref name="Olsen 1986">{{cite book |last=Olsen |first=O. Wilford |title=Animal Parasites: their life cycles and ecology |publisher=Dover |publication-place=New York |date=1986 |isbn=0-486-65126-6 |oclc=13123309 |pages=56<!--Proteromonas lacertae-->, 74–75<!--Opalina ranarum--> }}</ref>
oomycetes include some significant plant pathogens such as the cause of potato blight, ''[[Phytophthora infestans]]''.<ref name= "PlDis2011">{{cite journal |title=Potato and tomato late blight caused by ''Phytophthora infestans'': An overview of pathology and resistance breeding |last=Nowicki |first=Marcin |date=17 August 2011 |doi= 10.1094/PDIS-05-11-0458 |pmid=30731850 |display-authors=etal |volume=96 |issue=1 |journal=[[Plant Disease (journal)|Plant Disease]] |publisher=[[American Phytopathological Society]] |pages=4–17 |doi-access=free}}</ref> 
Diatoms are major contributors to global carbon cycles because they are the most important autotrophs in most marine habitats.<ref name="BGCC1">{{cite journal |doi=10.1029/2002GB002018 |title=Role of diatoms in regulating the ocean's silicon cycle |journal=Global Biogeochemical Cycles |volume=17 |issue=4 |year=2003 |last1=Yool |first1=Andrew |last2=Tyrrell |first2=Toby |article-number=2002GB002018 |pages=n/a |bibcode=2003GBioC..17.1103Y |citeseerx=10.1.1.394.3912 |s2cid=16849373 }}</ref> 
The brown algae, including familiar seaweeds like wrack and kelp, are major autotrophs of the intertidal and subtidal marine habitats.<ref name="Cock Peters Coelho 2011">{{Cite journal |last1=Cock |first1=J. Mark |last2=Peters |first2=Akira F. |last3=Coelho |first3=Susana M. |date=2011-08-09 |title=Brown algae |journal=Current Biology |volume=21 |issue=15 |pages=R573–R575 |doi=10.1016/j.cub.2011.05.006 |pmid=21820616 |doi-access=free |bibcode=2011CBio...21.R573C }}</ref> 
Some of the bacterivorous stramenopiles, such as ''Cafeteria'', are common and widespread consumers of bacteria, and thus play a major role in recycling carbon and nutrients within [[microbial food web]]s.<ref>{{cite web |last=Guiry |first=Wendy |title=Cafeteria T.Fenchel & D.J.Patterson 1988 |url=https://www.algaebase.org/search/genus/detail/?genus_id=43863 |website=AlgaeBase |access-date=17 March 2023 |date=7 April 2011}}</ref><ref>{{cite journal |last1=Fenchel |first1=T. |last2=Patterson |first2=D. J. |year=1988 |title=''Cafeteria roenbergensis'' nov. gen., nov. sp., a heterotrophic microflagellate from marine plankton |journal=Marine Microbial Food Webs |volume=3 |pages=9–19 |url=https://books.google.com/books?id=qPTwAAAAMAAJ }}</ref>

== Evolution ==

=== External ===

Stramenopiles are most closely related to alveolates and Rhizaria, all of which have tubular mitochondrial [[crista]]e and collectively form the [[SAR supergroup]], whose name is formed from their initials.<ref>Krylov, M. V.; Dobrovolskii, A. A.; Issi, I. V.; Michaelevich, B. I.; Podlipaev, S. A.; Reshetnyak, V. V.; Seravin, L. N.; et al. 1980. New concepts for the system of unicellular organisms. Trudy Zoologischkei Institut Akademiya Nayuk, SSSR 94:122–132.</ref><ref name="Derelle López-García Timpano Moreira 2016"/><ref name=Burki2008a>{{cite journal  |author1=Burki, F. |author2=Shalchian-Tabrizi |author3=Pawlowski, J. |title=Phylogenomics reveals a new 'megagroup' including most photosynthetic eukaryotes |journal=Biology Letters |volume=4 |issue=4 |pages=366–369 |date=August 2008 |pmid=18522922 |pmc=2610160 |doi=10.1098/rsbl.2008.0224 }}</ref> The ancestor of the SAR [[Supergroup (biology)|supergroup]] appears to have captured a unicellular photosynthetic [[Red algae|red alga]], and many stramenopiles, as well as members of other SAR groups such as the Rhizaria, still have plastids which retain the double membrane of the red alga and a double membrane surrounding it, for a total of four membranes.<ref name="Oborník Lukeš 2013 pp. 333–369">{{cite book |last1=Oborník |first1=Miroslav |last2=Lukeš |first2=Julius |title=International Review of Cell and Molecular Biology |chapter=Cell Biology of Chromerids |publisher=[[Elsevier]] |year=2013 |volume=306 |doi=10.1016/b978-0-12-407694-5.00008-0 |pages=333–369|pmid=24016529 |isbn=978-0-12-407694-5 }}</ref> In addition, species of [[Telonemia]], the sister group to SAR, exhibit heterokont flagella with tripartite mastigonemes, implying a more ancient origin of stramenopile characteristics.<ref name="Arpakorses">{{cite journal | last1=Tikhonenkov | first1=Denis V. | last2=Jamy | first2=Mahwash | last3=Borodina | first3=Anastasia S. | last4=Belyaev | first4=Artem O. | last5=Zagumyonnyi | first5=Dmitry G. | last6=Prokina | first6=Kristina I. | last7=Mylnikov | first7=Alexander P. | last8=Burki | first8=Fabien | last9=Karpov | first9=Sergey A. | title=On the origin of TSAR: morphology, diversity and phylogeny of Telonemia | journal=Open Biology | publisher=The Royal Society | volume=12 | issue=3 | year=2022 | article-number=210325 | issn=2046-2441 | doi=10.1098/rsob.210325| pmid=35291881 | pmc=8924772 | doi-access=free }}</ref>

{{clade|style=font-size:90%|label1=[[TSAR]]|1={{clade
|1=[[Telonemia]] [[File:Telonema_rivulare_(electron_micrography).jpg|60px]]|2={{clade
|label1=[[SAR supergroup|SAR]]|1={{clade
   |1=[[Rhizaria]] [[File:Ammonia tepida.jpg|60px]]
   |label2=[[Halvaria]]
   |2={{clade
      |1='''Stramenopiles''' [[File:Cafeteria roenbergensis atcc50561 Protsville (cropped).jpg|50px]]
      |2=[[Alveolata]] [[File:Ceratium furca.jpg|70px]]
      }}
   }}
}}
}}
}}

=== Internal ===

The following [[cladogram]] summarizes the evolutionary relationships between stramenopiles. The [[phylogenetic]] relationships of [[Bigyra]] vary greatly from one analysis to the next: it has been recovered as either [[monophyletic]]<ref name="Incisomonas">{{Cite journal|last1=Cavalier-Smith |first1=Thomas |last2=Scoble |first2=Josephine Margaret |title=Phylogeny of Heterokonta: Incisomonas marina, a uniciliate gliding opalozoan related to Solenicola (Nanomonadea), and evidence that Actinophryida evolved from raphidophytes |journal=European Journal of Protistology |date=2013 |volume=49 |issue= 3|pages=328–353 |doi= 10.1016/j.ejop.2012.09.002|pmid=23219323}}</ref><ref name="THAKUR_2019"/> or [[paraphyletic]]. When paraphyletic, the branching order of the bigyran groups also varies: in some studies, [[Sagenista]] is the most basal-branching clade,<ref name="Incisomonas"/><ref name="firstMAST6"/><ref name="Kaonashia">{{cite Q|Q123562228}}</ref> while in others [[Opalozoa]] is the most basal.<ref name="CHO_2023">{{cite Q|Q124719861}}</ref> Nonetheless, [[Platysulcea]] is consistently recovered as the [[sister clade]] to all other stramenopiles.<ref name="THAKUR_2019"/><ref name="firstMAST6"/> In addition, a flagellate species discovered in 2023, ''[[Kaonashia insperata]]'', remains in an uncertain phylogenetic position, but more closely related to [[Gyrista]] than to other clades.<ref name="Kaonashia"/>

{{clade|label1='''Stramenopiles'''|style=font-size:90%;|1={{clade
|1=''[[Platysulcus]]''
|2={{clade|state=dashed
 |1={{clade|label1=[[Sagenista]]|1={{clade
  |2=[[Eogyrea]]|bar2=black
  |1=[[Labyrinthulomycetes]] [[File:Aplanonet3.jpg|50px]]|barbegin1=black
  }}}}
 |2={{clade|state=dashed
  |1={{clade|label1=[[Opalozoa]]|1={{clade
   |2=[[Bicosoecida]] [[File:Cafeteria_roenbergensis_atcc50561_Protsville_(cropped).jpg|40px]]
   |bar1=black|barend2=black|1={{clade|label1=[[Placidozoa]]|1={{clade|1=[[Placididea]]|2={{clade|1=[[Nanomonadea]]|2=[[Opalinata]] [[File:Opalina_ranarum_Protsville.jpg|30px]]}}}}}}
   }}}}
  |2={{clade
   |1={{clade|label1=[[Gyrista]]|1={{clade
    |1={{clade
     |label1=[[Bigyromonada]]|1={{clade
      |1=[[Developea]]
      |2=[[Pirsonea]]
      }}
     |label2=[[Pseudofungi]]|2={{clade
      |1=[[Hyphochytriomycetes]]
      |2=[[Oomycetes]] [[File:Zoospore release.jpg|50px]]
      }}
     }}
    |2=[[Ochrophyta]] (=Heterokontophyta) [[File:Diatoms through the microscope.jpg|70px]]
    }}}}
   |2=''[[Kaonashia]]''
   }}
  }}
 }}
}}
|grouplabel1={{clade labels|label1=[[Bigyra]]|top1=28%}}
}}

== Classification ==

[[File:Paraphysomonas butcheri whole mount.jpg|200px|thumb|right|Electron micrograph of the protist ''Paraphysomonas butcheri''. It illustrates the stramenopile property – of having stiff hairs. The hairs attach to one longer flagellum, the other is without hairs (an arrangement also called 'heterokont', meaning "unequal"). The body of the flagellate is coated with delicate scales. ''Paraphysomonas'' feeds on bacteria, two of which lie near the hairy flagellum.]]

The classification of the stramenopiles according to Adl ''et al.'' (2019), with additions from newer research:<ref name="Adl 2019">{{cite journal |last1=Adl |first1=Sina M. |last2=Bass |first2=David |last3=Lane |first3=Christopher E. |last4=Lukeš |first4=Julius |last5=Schoch |first5=Conrad L. |last6=Smirnov |first6=Alexey |last7=Agatha |first7=Sabine |last8=Berney |first8=Cedric |last9=Brown |first9=Matthew W. |last10=Burki |first10=Fabien |last11=Cárdenas |first11=Paco |last12=Čepička |first12=Ivan |last13=Chistyakova |first13=Lyudmila |last14=del Campo |first14=Javier |last15=Dunthorn |first15=Micah |last16=Edvardsen |first16=Bente |last17=Eglit |first17=Yana |last18=Guillou |first18=Laure |last19=Hampl |first19=Vladimír |last20=Heiss |first20=Aaron A. |last21=Hoppenrath |first21=Mona |last22=James |first22=Timothy Y. |last23=Karnkowska |first23=Anna |last24=Karpov |first24=Sergey |last25=Kim |first25=Eunsoo |last26=Kolisko |first26=Martin |last27=Kudryavtsev |first27=Alexander |last28=Lahr |first28=Daniel J.G. |last29=Lara |first29=Enrique |last30=Le Gall |first30=Line |last31=Lynn |first31=Denis H. |last32=Mann |first32=David G. |last33=Massana |first33=Ramon |last34=Mitchell |first34=Edward A.D. |last35=Morrow |first35=Christine |last36=Park |first36=Jong Soo |last37=Pawlowski |first37=Jan W. |last38=Powell |first38=Martha J. |last39=Richter |first39=Daniel J. |last40=Rueckert |first40=Sonja |last41=Shadwick |first41=Lora |last42=Shimano |first42=Satoshi |last43=Spiegel |first43=Frederick W. |last44=Torruella |first44=Guifré |last45=Youssef |first45=Noha |last46=Zlatogursky |first46=Vasily |last47=Zhang |first47=Qianqian |display-authors=5 |title=Revisions to the Classification, Nomenclature, and Diversity of Eukaryotes |journal=Journal of Eukaryotic Microbiology |volume=66 |issue=1 |date=2019 |issn=1066-5234 |pmid=30257078 |pmc=6492006 |doi=10.1111/jeu.12691 |doi-access=free |pages=4–119}}</ref><ref name="8phyla"/>

* [[Platysulcea]] {{au|Cavalier-Smith 2017}}<ref name="THAKUR_2019">{{cite journal|first1=Rabindra |last1=Thakur|first2=Takashi |last2=Shiratori|first3=Ken-ichiro |last3=Ishida|title=Taxon-rich Multigene Phylogenetic Analyses Resolve the Phylogenetic Relationship Among Deep-branching Stramenopiles|journal=Protist|volume=170|issue=5|date=2019|article-number=125682|issn=1434-4610|doi=10.1016/j.protis.2019.125682|pmid=31568885 |s2cid=202865459 |url=https://www.sciencedirect.com/science/article/pii/S1434461018300865|url-access=subscription}}</ref>
* [[Bigyra]] {{au|Cavalier-Smith 1998, emend. 2006}}
** [[Opalozoa]] {{au|Cavalier Smith 1991, emend. 2006}}
*** [[Nanomonadea]] {{au|Cavalier-Smith 2012}}
*** [[Opalinata]] {{au|Wenyon 1926, emend. Cavalier-Smith 1997}} [=Slopalinida {{au|Patterson 1985}}]
*** [[Bicosoecida]] {{au|Grasse 1926, emend. Karpov 1998}}
** [[Sagenista]] {{au|Cavalier-Smith 1995}}
*** [[Labyrinthulomycetes]] {{au|Dick 2001}}
*** [[Pseudophyllomitidae]] {{au|Shiratori et al. 2016}}<ref name="firstMAST6">{{cite journal|first1=Takashi|last1=Shiratori|first2=Rabindra|last2=Thakur|first3=Ken-ichiro|last3=Ishida|title=Pseudophyllomitus vesiculosus (Larsen and Patterson 1990) Lee, 2002, a Poorly Studied Phagotrophic Biflagellate is the First Characterized Member of Stramenopile Environmental Clade MAST-6|journal=Protist|volume=168|issue=4|date=2017|pages=439–451|issn=1434-4610|doi=10.1016/j.protis.2017.06.004|pmid=28822908 |url=https://www.sciencedirect.com/science/article/pii/S1434461017300561|url-access=subscription|hdl=2241/00148460|hdl-access=free}}</ref>
* [[Gyrista]] {{au|Cavalier-Smith 1998}}
** [[Bigyromonada]] {{au|Cavalier-Smith 1998}}
*** [[Developea]] {{au|Karpov & Aleoshin 2016}}
*** [[Pirsoniales]] {{au|Cavalier-Smith 1998, emend. 2006}}
** [[Pseudofungi]] {{au|Cavalier-Smith 1986}}
*** [[Hyphochytriales]] {{au|Sparrow 1960}}
*** [[Peronosporomycetes]] {{au|Dick 2001}} [=Oomycetes {{au|Winter 1897, emend. Dick 1976}}]
** [[Actinophryidae]] {{au|Claus 1874, emend. Hartmann 1926}}
** [[Ochrophyta]] {{au|Cavalier-Smith 1986, emend. Cavalier-Smith & Chao 1996}}
*** [[Chrysista]] {{au|Cavalier-Smith 1986}}
**** [[Chrysoparadoxophyceae]] {{au|Wetherbee 2019}}<ref name="Chrysoparadoxophyceae">{{cite journal |last1=Wetherbee |first1=Richard |last2=Jackson |first2=Christopher J. |last3=Repetti |first3=Sonja I. |last4=Clementson |first4=Lesley A. |last5=Costa |first5=Joana F. |last6=van de Meene |first6=Allison |last7=Crawford |first7=Simon |last8=Verbruggen |first8=Heroen |title=The golden paradox – a new heterokont lineage with chloroplasts surrounded by two membranes |journal=Journal of Phycology |volume=55 |issue=2 |date=2019 |doi=10.1111/jpy.12822 |doi-access=free |pages=257–278 |pmid=30536815 |bibcode=2019JPcgy..55..257W |url=http://minerva-access.unimelb.edu.au/bitstreams/9b9db783-0e2e-5b41-a2d4-22570a2465ae/download |access-date=14 October 2025}}</ref>
**** [[Chrysophyceae]] {{au|Pascher 1914}}
**** Chloromorophyceae (''[[nomen dubium]]'')<ref>{{cite journal |last1=Medlin |first1=L.K. |last2=Desdevises |first2=Y.|title=Sequence analysis confirms a new algal class |journal=Vie et Milieu/Life & Environment |date=2018 |volume=62 |issue=2–3 |pages=151–155 |url=https://hal.science/hal-02144544}}</ref>
**** [[Eustigmatophyceae]] {{au|Hibberd & Leedale 1971}}
**** [[Olisthodiscophyceae]] {{au|Barcytė, Eikrem & M.Eliáš, 2021}}<ref name="Graf_2021">{{cite journal |last1=Graf |first1=Louis |last2=Yoon |first2=Hwan Su |title=Olisthodiscophyceae, the 17th heterokont algal class |journal=Journal of Phycology |date=21 July 2021 |volume=57 |issue=4 |pages=1091–1093 |doi=10.1111/jpy.13184 |pmid=34289104 |bibcode=2021JPcgy..57.1091G |s2cid=236175098 }}</ref><ref name="Bacryté_2021">{{cite journal |last1=Barcytė |first1=Dovilė |last2=Eikrem |first2=Wenche |last3=Engesmo |first3=Anette |last4=Seoane |first4=Sergio |last5=Wohlmann |first5=Jens |last6=Horák |first6=Aleš |last7=Yurchenko |first7=Tatiana |last8=Eliáš |first8=Marek |title=''Olisthodiscus'' represents a new class of Ochrophyta |journal=Journal of Phycology |date=2 March 2021 |volume=57 |issue=4 |pages=1094–1118 |doi=10.1111/jpy.13155 |pmid=33655496 |bibcode=2021JPcgy..57.1094B |s2cid=232101186 |url=http://urn.nb.no/URN:NBN:no-89151 |hdl=10852/86515 |hdl-access=free }}</ref>
**** [[Phaeophyceae]] {{au|Hansgirg 1886}}
**** [[Phaeosacciophyceae]] {{au|R.A.Andersen, L.Graf & H.S.Yoon 2020}}<ref name="Phaeosacciophyceae">{{cite journal|vauthors=Graf L, Yang EC, Han KY, Küpper FC, Benes KM, Oyadomari JK, ((Herbert RJH)), Verbruggen H, Wetherbee R, Andersen RA, Yoon HS|title=Multigene Phylogeny, Morphological Observation and Re-examination of the Literature Lead to the Description of the Phaeosacciophyceae Classis Nova and Four New Species of the Heterokontophyta SI Clade|journal=Protist|date=December 2020|volume=171|issue=6|article-number=125781|doi=10.1016/j.protis.2020.125781|pmid=33278705|s2cid=227315556 |doi-access=free}}</ref>
**** [[Phaeothamniophyceae]] {{au|Andersen & Bailey in Bailey et al. 1998}}
**** [[Raphidophyceae]] {{au|Chadefaud 1950, emend. Silva 1980}}
**** [[Schizocladiophyceae]] {{au|Henry, Okuda & Kawai, 2003}}
**** [[Synchromophyceae]] {{au|S.Horn & C.Wilhelm 2007}} [=Picophagea {{au|Cavalier-Smith 2006, emend. 2017}}]
**** [[Xanthophyceae]] {{au|Allorge 1930, emend. Fritsch 1935}} [Heterokontae {{au|Luther 1899}}; Heteromonadea {{au|Leedale 1983}};  Xanthophyta {{au|Hibberd 1990}}]
*** [[Diatomista]] {{au|Derelle et al. 2016, emend. Cavalier-Smith 2017}}
**** [[Bolidophyceae]] {{au|Guillou et al. 1999}}
**** [[Diatomeae]] {{au|Dumortier 1821}} [=Bacillariophyta {{au|Haeckel 1878}}]
**** [[Dictyochophyceae]] {{au|Silva 1980}}
**** [[Pelagophyceae]] {{au|Andersen & Saunders 1993}}
**** [[Pinguiophyceae]] {{au|Kawachi et al. 2003}}

== Notes ==
{{notelist}}

== References ==

{{reflist|group=nb}}
{{reflist|30em|refs=
<ref name="8phyla">{{cite journal |last=Cavalier-Smith |first=Thomas  |title=Kingdom Chromista and its eight phyla: a new synthesis emphasising periplastid protein targeting, cytoskeletal and periplastid evolution, and ancient divergences|date=January 2018|journal=Protoplasma |pages=297–357 |volume=255 |issue=1 |doi=10.1007/s00709-017-1147-3 |pmid=28875267 |pmc=5756292 |bibcode=2018Prpls.255..297C }}</ref>

<ref name="Adl 2005">{{cite Q|Q22065654}}</ref>
}}

== External links ==
* [http://tolweb.org/tree?group=Stramenopiles&contgroup=Eukaryotes Tree of Life Web Project: Stramenopiles]

{{Eukaryota|D.}}
{{Stramenopile}}
{{Taxonbar|from1=Q461622|from2=Q18744565|from3=Q3500019}}

[[Category:Protists]]