Article · Wikipedia archive · Last revised Jul 19, 2026

Tetrabaena

Tetrabaena is a monotypic genus of green algae containing the species Tetrabaena socialis. It primarily occurs in freshwater, although it has been found in saltwater on at least one occasion. Although rare, it has a cosmopolitan distribution and has even been found from Antarctica.

Last revised
Jul 19, 2026
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Tetrabaena
Tetrabaena socialis swimming
Scientific classification Edit this classification
Kingdom: Plantae
Division: Chlorophyta
Class: Chlorophyceae
Order: Chlamydomonadales
Family: Tetrabaenaceae
Genus: Tetrabaena
Fromentel
Species:
T. socialis
Binomial name
Tetrabaena socialis
(Dujardin) H.Nozaki & M.Itoh
Synonyms
  • Cryptomonas socialis Dujardin 1841
  • Gonium sociale (Dujardin) Warming 1876
  • Tetrabaena dujardinii Fromentel 1874; heterotypic
  • Tetragonium lacustre West & G.S.West 1896; heterotypic

Tetrabaena is a monotypic genus of green algae containing the species Tetrabaena socialis.123 It primarily occurs in freshwater, although it has been found in saltwater on at least one occasion.3 Although rare, it has a cosmopolitan distribution and has even been found from Antarctica.4

Description

Tetrabaena are colonial organisms, consisting of four cells. The four cells are arranged in a square, and attached to each other by the extensions of their cellular sheaths. Cells are ovoid, somewhat asymmetrical in shape. It is a motile flagellate, possessing two equal flagella per cell23 and two contractile vacuoles at the base of the flagella. Cells also contain a single cup-shaped chloroplast with a basal pyrenoid.4 Although Tetrabaena possess an eyespot, it does not appear to function as a photoreceptor.5

Tetrabaena are capable of sexual reproduction, and are isogamous.4

Research significance

Tetrabaena is a member of the order Chlamydomonadales, a model lineage used in the study of the origins of multicellular organisms from single-celled ancestors.23 Within Chlamydomonadales, it is notable for being the colonial species with the smallest number of cells (4), placing it at the boundary between single- and multi-cellularity. As such, it has been characterized as the "simplest integrated multicellular organism."2

Genomic data and molecular clock analysis suggest that Tetrabaena socialis may contain cryptic species.3

References

References

  1. Laber, Bernd (January 6, 2006). "Green Algae from a Garden Pond: Tetrabaena socialis". Micscape Magazine. Retrieved January 27, 2015.
  2. Arakaki, Yoko; Kawai-Toyooka, Hiroko; Hamamura, Yuki; Higashiyama, Tetsuya; Noga, Akira; Hirono, Masafumi; Olson, Bradley J. S. C.; Nozaki, Hisayoshi (2013-12-11). "The Simplest Integrated Multicellular Organism Unveiled". PLOS ONE. 8 (12) e81641. Bibcode:2013PLoSO...881641A. doi:10.1371/journal.pone.0081641. ISSN 1932-6203. PMC 3859500. PMID 24349103.
  3. Lindsey, Charles Ross; Knoll, Andrew H.; Herron, Matthew D.; Rosenzweig, Frank (2024-04-10). "Fossil-calibrated molecular clock data enable reconstruction of steps leading to differentiated multicellularity and anisogamy in the Volvocine algae". BMC Biology. 22 (1): 79. Bibcode:2024BMCB...22...79L. doi:10.1186/s12915-024-01878-1. ISSN 1741-7007. PMC 11007952. PMID 38600528.
  4. Nakada, Takashi; Nozaki, Hisayoshi (2014). "Chapter 6. Flagellate Green Algae". In Wehr, John D.; Sheath, Robert G.; Kociolek, J. Patrick (eds.). Freshwater Algae of North America: Ecology and Classification (2 ed.). Elsevier Inc. pp. 265–313. ISBN 978-0-12-385876-4.
  5. Tanno, Asuka; Tokutsu, Ryutaro; Arakaki, Yoko; Ueki, Noriko; Minagawa, Jun; Yoshimura, Kenjiro; Hisabori, Toru; Nozaki, Hisayoshi; Wakabayashi, Ken-Ichi (2021). "The four-celled Volvocales green alga Tetrabaena socialis exhibits weak photobehavior and high-photoprotection ability". PLOS ONE. 16 (10) e0259138. Bibcode:2021PLoSO..1659138T. doi:10.1371/journal.pone.0259138. PMC 8547699. PMID 34699573.