SAR supergroup

Source: Wikipedia, the free encyclopedia.
"TSAR" redirects here. Not to be confused with Tsar or TSAR Publications.

SAR
Temporal range: 736–0 Ma[1]
Scientific classification Edit this classification
Domain: Eukaryota
Clade: Diaphoretickes
Clade:
TSAR
Clade: SAR
Burki et al., 2007
Infrakingdoms
Synonyms
  • Harosa Cavalier-Smith, 2010

SAR or Harosa is a highly diverse

rhizarians.[3][4][5] It is a node-based taxon, including all descendants of the three groups' last common ancestor,[6] and comprises most of the now-rejected Chromalveolata.[2] Their sister group has been found to be telonemids, with which they make up the TSAR clade.[7]

Etymology

The name SAR is an acronym derived from the first letters of its three constituent clades;[a] it has been alternatively spelled "RAS".[6][8] The term "Harosa" (at the subkingdom level) has also been used, with Stramenopiles replaced by its synonym Heterokonta in this variant of the acronym.[9]

History of discovery

Before the discovery of the SAR supergroup,

secondary endosymbiosis of red algae through a common ancestor.[2] Meanwhile, Rhizaria was traditionally considered to be a separate supergroup. More recent phylogenetic studies confirmed that stramenopiles and alveolates diverged with rhizarians as part of the SAR lineage.[10] This clade has been found by later phylogenomic studies to be robustly characterized compared to other supergroups.[7]

This groups excludes haptophytes and cryptomonads, hypothesized to have acquired plastids in separate endosymbiosis events,[11] leading Okamoto et al. (2009) to propose the clade Hacrobia to accommodate them.[12]

Diversity

The SAR supergroup encompasses a variety of morphologies and ecological niches, from microscopic

endosymbiosis events, acquiring plastids of red algal origin,[13][11] while chlorarachniophyte rhizarians captured plastids from green algae, retaining vestigial nucleomorphs.[14]

It has been estimated that SAR encompasses up to half of all eukaryotic diversity.[2]

Owing to the clade's discovery through

cortical alveoli.[15]

Nonetheless, studies of telonemids, believed to be the sister group to SAR, 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.[7]

Internal phylogeny

A 2021 analysis places Alveolata and Stramenopiles in Halvaria, as sister to Rhizaria.[11]

TSAR

Telonemia

SAR/
Harosa

See also

Notes

  1. ^ As a formal taxon, "Sar" has only its first letter capitalized, while the earlier abbreviation, SAR, retains all uppercase letters. Both names denote the same group of organisms, unless further taxonomic revisions deem otherwise.

References

  1. Wikidata Q24614721
    .
  2. ^
    PMID 31606140
    .
  3. ^
    PMID 17726520
    .
  4. PMID 19237557
    .
  5. PMID 18799712
    .
  6. ^
    PMID 23020233
    .
  7. ^
    PMID 30668767
    .
  8. S2CID 512766. Archived from the original (PDF) on 2019-08-20.{{cite journal}}: CS1 maint: DOI inactive as of January 2024 (link
    )
  9. PMID 20031978
    .
  10. ISBN 978-0-544-85993-7
    .
  11. ^
    PMID 33767194
    .
  12. PMID 24789819
    .
  13. S2CID 51945442
    .
  14. S2CID 51989
    .
  15. doi:10.1002/bies.201700198
    .
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