Eukaryotic supergroup that comprises stramenopiles, alveolates and rhizarians
SAR [ nb 1] diverse clade ofeukaryotes , often considered asupergroup ,[ 4] stramenopiles (heterokonts),alveolates , andrhizarians .[ 5] [ 6] [ 7] node-based taxon (under theSar name), including all descendants of the three groups' last common ancestor,[ 8] Chromalveolata .[ 4] sister group might betelonemids , with which they would make up theTSAR (sometimes calledT-SAR [ 9] [ 10] [ 11] [ 12] [ 13] [ 14] [ 15] Harosa is usedsynonymously with TSAR byCavalier-Smith in 2022.[ 16]
The name SAR is anacronym derived from the first letters of its three constituent clades; it has been alternatively spelled RAS.[ 17] subkingdom level) has also been used, with Stramenopiles replaced by its synonym Heterokonta in this variant of the acronym.[ 18]
History of discovery [ edit ] Before the discovery of the SAR supergroup,stramenopiles andalveolates were classified in the supergroupChromalveolata alongsidehaptophytes andcryptomonads , being believed to have acquired plastids throughsecondary endosymbiosis ofred algae through a common ancestor.[ 4] Rhizaria was traditionally considered to be a separate supergroup. More recentphylogenetic studies confirmed that stramenopiles and alveolates diverged with rhizarians as part of the SAR lineage.[ 19] [ 13]
This group excludes haptophytes and cryptomonads, hypothesized to have acquired plastids in separate endosymbiosis events,[ 20] et al. (2009) to propose the cladeHacrobia to accommodate them.[ 21]
The SAR supergroup encompasses a variety of morphologies and ecological niches, from microscopiczoo - andphytoplankton to massivekelp forests . The group includes both photosynthetic and non-photosynthetic forms. Photosynthesis arose independently across variousstramenopile andalveolate lineages through secondary or higher-orderendosymbiosis events, acquiring plastids ofred algal origin,[ 22] [ 20] chlorarachniophyte rhizarians captured plastids fromgreen algae , retaining vestigialnucleomorphs .[ 23]
It has been estimated that SAR encompasses up to half of all eukaryotic diversity.[ 4]
Owing to the clade's discovery throughphylogenomics , there are no known synapomorphies uniting its various members.[ 5] mastigonemes ), while Alveolata is united by the presence ofcortical alveoli .[ 24]
Nonetheless, studies oftelonemids have revealed characteristics such as tripartite hair and peripheral vacuoles, potentially homologous to similar structures in stramenopiles and alveolates. This brings into light the possibility of these structures being ancestrally shared by the clade, with cortical alveoli originating from peripheral vacuoles under this hypothesis.[ 13]
A 2021 analysis places Alveolata and Stramenopiles inHalvaria , as sister to Rhizaria.[ 20]
^ As a formaltaxon , Sar has only its first letter capitalized, while the earlier abbreviation, SAR, retains all uppercase letters. Both names denote the same group oforganisms .[ 3] ^ Laura Wegener Parfrey , Daniel J G Lahr,Andrew H Knoll ,Laura A Katz (16 August 2011)."Estimating the timing of early eukaryotic diversification with multigene molecular clocks" (PDF) .Proceedings of the National Academy of Sciences of the United States of America 108 (33):13624– 9.Bibcode :2011PNAS..10813624P .doi :10.1073/PNAS.1110633108 .ISSN 0027-8424 .PMC 3158185 PMID 21810989 .Wikidata Q24614721 .^ Adl, Sina M.; Bass, David; Lane, Christopher E.; Lukeš, Julius; Schoch, Conrad L.; Smirnov, Alexey; Agatha, Sabine; Berney, Cedric; Brown, Matthew W.; Burki, Fabien; Cárdenas, Paco; Čepička, Ivan; Chistyakova, Lyudmila; del Campo, Javier; Dunthorn, Micah (2019)."Revisions to the Classification, Nomenclature, and Diversity of Eukaryotes" .Journal of Eukaryotic Microbiology .66 (1):4– 119.doi :10.1111/jeu.12691 ISSN 1550-7408 .PMC 6492006 PMID 30257078 . ^ Adl, Sina M.; Simpson, Alastair G. B.; Lane, Christopher E.; Lukeš, Julius; Bass, David; Bowser, Samuel S.; Brown, Matthew W.; Burki, Fabien; Dunthorn, Micah; Hampl, Vladimir; Heiss, Aaron; Hoppenrath, Mona; Lara, Enrique; le Gall, Line; Lynn, Denis H. (September 2012)."The Revised Classification of Eukaryotes" .Journal of Eukaryotic Microbiology .59 (5):429– 514.doi :10.1111/j.1550-7408.2012.00644.x .ISSN 1066-5234 .PMC 3483872 PMID 23020233 . ^a b c d Burki, Fabien; Roger, Andrew J.; Brown, Matthew W.; Simpson, Alastair G.B. (January 2020)."The New Tree of Eukaryotes" .Trends in Ecology & Evolution .35 (1):43– 55.Bibcode :2020TEcoE..35...43B .doi :10.1016/j.tree.2019.08.008 PMID 31606140 . ^a b Burki F, Shalchian-Tabrizi K, Minge M, Skjaeveland A, Nikolaev SI, Jakobsen KS, Pawlowski J (August 2007). Butler G (ed.)."Phylogenomics reshuffles the eukaryotic supergroups" .PLOS ONE .2 (8) e790.Bibcode :2007PLoSO...2..790B .doi :10.1371/journal.pone.0000790 PMC 1949142 PMID 17726520 . ^ Hampl V, Hug L, Leigh JW, Dacks JB, Lang BF, Simpson AG, Roger AJ (March 2009)."Phylogenomic analyses support the monophyly of Excavata and resolve relationships among eukaryotic "supergroups" .Proceedings of the National Academy of Sciences of the United States of America .106 (10):3859– 64.Bibcode :2009PNAS..106.3859H .doi :10.1073/pnas.0807880106 PMC 2656170 PMID 19237557 . ^ Frommolt R, Werner S, Paulsen H, Goss R, Wilhelm C, Zauner S, et al. (December 2008)."Ancient recruitment by chromists of green algal genes encoding enzymes for carotenoid biosynthesis" .Molecular Biology and Evolution .25 (12):2653– 67.doi :10.1093/molbev/msn206 PMID 18799712 . ^ Adl SM, Simpson AG, Lane CE, Lukeš J, Bass D, Bowser SS, et al. (September 2012)."The revised classification of eukaryotes" .The Journal of Eukaryotic Microbiology .59 (5):429– 93.doi :10.1111/j.1550-7408.2012.00644.x .PMC 3483872 PMID 23020233 . ^ Yazaki, Euki; Kume, Keitaro; Shiratori, Takashi; Eglit, Yana; Tanifuji, Goro; Harada, Ryo; Simpson, Alastair G. B.; Ishida, Ken-ichiro; Hashimoto, Tetsuo; Inagaki, Yuji (2020-09-02)."Barthelonids represent a deep-branching metamonad clade with mitochondrion-related organelles predicted to generate no ATP" .Proceedings of the Royal Society B: Biological Sciences .287 (1934) 20201538.doi :10.1098/rspb.2020.1538 .PMC 7542792 PMID 32873198 . ^ Yazaki, Euki; Yabuki, Akinori; Imaizumi, Ayaka; Kume, Keitaro; Hashimoto, Tetsuo; Inagaki, Yuji (2021-08-31),Phylogenomics invokes the clade housing Cryptista, Archaeplastida, and Microheliella maris doi :10.1101/2021.08.29.458128 , retrieved2025-05-17 ^ Yazaki, Euki; Yabuki, Akinori; Imaizumi, Ayaka; Kume, Keitaro; Hashimoto, Tetsuo; Inagaki, Yuji (2022-04-13)."The closest lineage of Archaeplastida is revealed by phylogenomics analyses that include Microheliella maris" .Open Biology .12 (4) 210376.doi :10.1098/rsob.210376 .PMC 9006020 PMID 35414259 . ^ Yazaki, Euki; Harada, Ryo; Isogai, Ryu; Bamba, Kohei; Ishida, Ken-ichiro; Inagaki, Yuji; Shiratori, Takashi (2025-06-04)."Glissandra oviformis n. sp.: a novel predatory flagellate illuminates the character evolution within the eukaryotic clade CRuMs" .Open Biology .15 (6) 250057.doi :10.1098/rsob.250057 .PMC 12133344 PMID 40460873 . ^a b c Strassert JF, Jamy M, Mylnikov AP, Tikhonenkov DV, Burki F (April 2019). Shapiro B (ed.)."New Phylogenomic Analysis of the Enigmatic Phylum Telonemia Further Resolves the Eukaryote Tree of Life" .Molecular Biology and Evolution .36 (4):757– 765.doi :10.1093/molbev/msz012 .PMC 6844682 PMID 30668767 . ^ Yazaki, Euki; Yabuki, Akinori; Imaizumi, Ayaka; Kume, Keitaro; Hashimoto, Tetsuo; Inagaki, Yuji (2022)."The closest lineage of Archaeplastida is revealed by phylogenomics analyses that include Microheliella maris" .Open Biol .12 (4) 210376.doi :10.1098/rsob.210376 .PMC 9006020 ^ Torruella, Guifré; Galindo, Luis Javier; Moreira, David; López-García, Purificación (27 August 2024)."Phylogenomics of neglected flagellated protists supports a revised eukaryotic tree of life" .bioRxiv.org .doi :10.1101/2024.05.15.594285 . Retrieved12 November 2024 . ^ Cavalier-Smith, Thomas (2022-05-01)."Ciliary transition zone evolution and the root of the eukaryote tree: implications for opisthokont origin and classification of kingdoms Protozoa, Plantae, and Fungi" .Protoplasma .259 (3):487– 593.doi :10.1007/s00709-021-01665-7 .ISSN 1615-6102 .PMC 9010356 PMID 34940909 . ^ Baldauf SL (2008)."An overview of the phylogeny and diversity of eukaryotes" (PDF) .Journal of Systematics and Evolution .46 (3):263– 273.doi :10.3724/SP.J.1002.2008.08060 (inactive 12 July 2025).S2CID 512766 . Archived fromthe original (PDF) on 2019-08-20. {{cite journal }}: CS1 maint: DOI inactive as of July 2025 (link )^ Cavalier-Smith T (June 2010)."Kingdoms Protozoa and Chromista and the eozoan root of the eukaryotic tree" .Biology Letters .6 (3):342– 5.doi :10.1098/rsbl.2009.0948 .PMC 2880060 PMID 20031978 . ^ Dawkins R, Wong Y (2016).Ancestor's Tale . Houghton Mifflin Harcourt. pp. 573– 577.ISBN 978-0-544-85993-7 ^a b c Strassert JF; Irisarri I; Williams TA; Burki F (March 2021)."A molecular timescale for eukaryote evolution with implications for the origin of red algal-derived plastids" .Nature Communications .12 (1): 1879.Bibcode :2021NatCo..12.1879S .doi :10.1038/s41467-021-22044-z .PMC 7994803 PMID 33767194 . ^ Burki F (May 2014)."The eukaryotic tree of life from a global phylogenomic perspective" .Cold Spring Harbor Perspectives in Biology .6 (5) a016147.doi :10.1101/cshperspect.a016147 .PMC 3996474 PMID 24789819 . ^ McFadden, G. I. (2001). "Primary and secondary endosymbiosis and the origin of plastids".Journal of Phycology .37 (6):951– 959.Bibcode :2001JPcgy..37..951M .doi :10.1046/j.1529-8817.2001.01126.x .S2CID 51945442 . ^ Archibald JM (January 2009)."The puzzle of plastid evolution" .Current Biology .19 (2): R81-8.Bibcode :2009CBio...19..R81A .doi :10.1016/j.cub.2008.11.067 PMID 19174147 .S2CID 51989 . ^ Grattepanche, Jean David; et al. (March 2018)."Microbial Diversity in the Eukaryotic SAR Clade: Illuminating the Darkness Between Morphology and Molecular DataDarkness Between Morphology and Molecular Data" .BioEssays .doi :10.1002/bies.201700198
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