Yellow-green algae or the Xanthophyceae (xanthophytes) are an important group of heterokont algae. Most live in fresh water, but some are found in marine and soil habitats. They vary from single-celled flagellates to simple colonial and filamentous forms. Xanthophyte chloroplasts contain the photosynthetic pigments chlorophyll a, chlorophyll c, β-carotene, and the carotenoid diadinoxanthin.[7] Unlike other Stramenopiles (heterokonts), their chloroplasts do not contain fucoxanthin, which accounts for their lighter colour. Their storage polysaccharide is chrysolaminarin.[7] Xanthophyte cell walls are produced of cellulose and hemicellulose.[7] They appear to be the closest relatives of the brown algae.
Classifications
The species now placed in the Xanthophyceae were formerly included in the Chlorophyceae.[8] In 1899, Lüther created the group Heterokontae for green algae with unequal flagella. Pascher (1914) included the Heterokontae in the Chrysophyta. In 1930, Allorge renamed the group as Xanthophyceae.
The monadoid (unicellular flagellates) and also sometimes the amoeboid species have been included by some authors in the Protozoa or Protista,[9][10] as order Heterochloridina (e.g., Doflein and Reichenow, 1927-1929[11]), as class Xanthomonadina, with orders Heterochloridea and Rhizochloridea (e.g., Deflandre, 1956[12]), as order Heterochlorida (e.g., Hall, 1953,[13] Honigberg et al., 1964[14]), as order Heteromonadida (e.g., Leedale, 1983[15]), or as subclass Heterochloridia (e.g., Puytorac et al., 1987[16]). These groups are called ambiregnal protists, as names for these have been published under either or both of the ICZN and the ICN.
AlgaeBase (2020)
Xanthophyceae have been divided into the following five orders in some classification systems:[17]
Lüther (1899)
Classification according to Lüther (1899):[19][20]
- Class Heterokontae
- Order Chloromonadales
- Order Confervales
Pascher (1912)
Classification according to Pascher (1912):[21]
- Heterokontae
- Heterochloridales
- Heterocapsales
- Heterococcales
- Heterotrichales
- Heterosiphonales
Fritsch (1935)
Fritsch (1935) recognizes the following orders in the class Xanthophyceae:[22]
- Order Heterochloridales
- Order Heterococcales
- Order Heterotrichales
- Order Heterosiphonales
Smith (1938)
In the classification of Smith (1938), there are six orders in the class Xanthophyceae, placed in the division Chrysophyta:
Pascher (1939)
Pascher (1939) recognizes 6 classes in Heterokontae:[23]
- Class Heterochloridineae
- Class Rhizochloridineae
- Class Hetcrocapsineae
- Class Heterococcincae
- Class Hetcrotrichineae
- Class Heterosiphonineae
Copeland (1956)
Copeland (1956) treated the group as order Vaucheriacea:[24]
- Kingdom Protoctista
- Phylum Phaeophyta
- Class Heterokonta
- Order Vaucheriacea
- Family Chlorosaccacea
- Family Mischococcacea
- Family Chlorotheciacea
- Family Botryococcacea
- Family Stipitococcacea
- Family Chloramoebacea
- Family Tribonematacea
- Family Phyllosiphonacea
Ettl (1978), van den Hoek et al. (1995)
In a classification presented by van den Hoek, Mann and Jahns (1995), based on the level of organization of the thallus, there are seven orders:
- Order Chloramoebales (e.g., Chloromeson) - flagellate organisms
- Order Rhizochloridales (e.g., Rhizochloris, Myxochloris) - ameboid organisms
- Order Heterogloeales (e.g., Gloeochloris) - palmelloid (tetrasporal) organisms
- Order Mischococcales (e.g., Chloridella, Botrydiopsis, Characiopsis, Ophiocytium) - coccoid organisms
- Order Tribonematales (e.g., Tribonema, Heterococcus, Heterodendron) - filamentous organization
- Order Botrydiales (e.g., Botrydium) - siphonous organization; sexual reproduction isogamous or anisogamous
- Order Vaucheriales (e.g., Vaucheria) - siphonous organization; sexual reproduction oogamous
These are the same orders of the classification of Ettl (1978),[25] an updated version of the classic work by Pascher (1939). Ultrastructural and molecular studies shows that the Mischococcales might be paraphyletic, and the Tribonematales and Botrydiales polyphyletic,[26] and suggests two orders at most be used until the relationships within the division are sorted.[27]
Maistro et al. (2009)
Informal groups, according to Maistro et al. (2009):[28]
- Botrydiopsalean clade
- Chlorellidialean clade
- Tribonematalean clade
- Vaucherialean clade
Unicellular flagellates, amoeboid and palmelloid taxa were not included in this study.
Adl et al. (2005, 2012)
According to Adl et al. (2005, 2012):[27][29]
- Tribonematales (genera Botrydium, Bumilleriopsis, Characiopsis, Chloromeson, Heterococcus, Ophiocytium, Sphaerosorus, Tribonema, Xanthonema)
- Vaucheriales (genus Vaucheria)
Stipitococcus capense (Rhizochloridales)
Ophiocytium arbusculum (Mischococcales), formerly Sciadium arbuscula
See also
References
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^ Allorge, P (1930). "Heterocontées ou Xanthophycées?". Rev. Alg. 5: 230.
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^ Fritsch, F.E. (1935) The Structure and Reproduction of the Algae. Volume I. Introduction, Chlorophyceae, Xanthophyceae, Chrysophyceae, Bacillariophyceae, Cryptophyceae, Dinophyceae, Chloromonadineae, Euglenineae, Colourless Flagellata. Cambridge University Press, Cambridge.
-
^ Lüther, A. (1899). "Über Chlorosaccus eine neue Gattung der Süsswasseralgen". Bihang Til Kongliga Svenska Vetenskaps-Akademiens Handlingar. 24: 1–22. OCLC 178060545.
-
^ Hibberd, D. J. (February 1981). "Notes on the taxonomy and nomenclature of the algal classes Eustigmatophyceae and Tribophyceae (synonym Xanthophyceae)". Botanical Journal of the Linnean Society. 82 (2): 93–119. doi:10.1111/j.1095-8339.1981.tb00954.x.
-
^ Leedale, G.F. (1985). "Order 5, Heteromonadida Leedale, 1983". In Lee, John J.; Hutner, Seymour Herbert; Bovee, Eugene C. (eds.). An illustrated Guide to Protozoa. Lawrence, Kansas: Society of Protozoologists. pp. 70–.
-
^ Hiberd, D. J. (1990). "Phylum Xanthophyta". In Margulis, L.; Corliss, J. O.; Melkonian, M.; et al. (eds.). Handbook of Protoctista. Boston, Massachusetts, USA: Jones and Bartlett Publishers. pp. 686–97.
-
^ a b c Stace, Clive A. (1991). Plant Taxonomy and Biosystematics. Cambridge University Press. ISBN 978-0-521-42785-2.
-
^ Chapman, V. J. An Introduction to the Study of Algae. University Press, Cambridge; The Macmillan Company, New York, 1941, p. 18, [1].
-
^ Copeland (1956), p. 63
-
^ Fernández-Galiano, D (1990). "Las nuevas clasificaciones de los organismos eucarióticos unicelulares. Protistología versus Protozoología" (PDF). Rev. R. Soc. Esp. Hist Nat., (Secc. Biol.). 85 (1–4): 107–125.
-
^ Doflein, F. & Reichenow, E. 1927-1929. Lehrbuch der Protozoenkunde, 5th ed, G. Fischer, Jena. 1262 p.
-
^ Deflandre, G. (1952). In: Grassé, P.-P. (Ed.). Traité de Zoologie. Vol. 1, fasc. 1. Phylogénie. Protozoaries: Generalités, Flagellés. Masson et Cie, Paris. pp. 212, 217, 220.
-
^ Hall, R.P., 1953. Protozoology. Prentice-Hall, New York, [2],
-
^ Honigberg, B.M.; Balamuth, W.; Bovee, E.C.; Corliss, J.O.; Gojdics, M.; Hall, R.P.; Kudo, R.R.; Levine, N.D.; Loeblich, A.R.Jr.; Weiser, J.; Wenrich, D.H. (1964). "A revised classification of the phylum Protozoa". Journal of Protozoology. 11 (1): 7–20. doi:10.1111/j.1550-7408.1964.tb01715.x. PMID 14119564.
-
^ Leedale, G.F. (1985). "Order 5, Heteromonadida Leedale, 1983". In Lee, John J.; Hutner, Seymour Herbert; Bovee, Eugene C. (eds.). An illustrated Guide to Protozoa. Lawrence, Kansas: Society of Protozoologists. pp. 70–.
-
^ Puytorac, P. de, Grain, J., Mignot, J.P. Précis de protistologie. Lubrecht & Cramer Ltd, 1987. 581 p.
-
^ Guiry, M.D.; Guiry, G.M. (2020). "Xanthophyceae". AlgaeBase. National University of Ireland, Galway. Retrieved 2 June 2020.
-
^ Christensen, T. 1987. Seaweeds of the British Isles. Volume 4 Tribophyceae (Xanthophyceae). British Museum (Natural History), London ISBN 0-565-00980-X
-
^ Lüther, A (1899). "Über Chlorosaccus eine neue Gattung der Süsswasseralgen". Bihang Til Kongliga Svenska Vetenskaps-Akademiens Handlingar. 24: 1–22.
-
^ Pascher (1912), p. 9, [3].
-
^ Pascher, A (1912). "Zur Gliederung der Heterokonten (Kieine Beiträge zur Kenntnis unserer Mikroflora 3)". Hedwigia. 53: 6–22.
-
^ Fritsch, F.E. (1935) The Structure and Reproduction of the Algae. Volume I. Introduction, Chlorophyceae. Xanthophyceae, Chrysophyceae, Bacillariophyceae, Cryptophyceae, Dinophyceae, Chloromonadineae, Euglenineae, Colourless Flagellata. Vol. I, Cambridge University Press, Cambridge, [4].
-
^ Pascher, A., 1939. Heterokonten. In: Rabenhorsts Kryptogamen-Flora von Deutschland, Österreich und der Schweiz. Aufl. 2 Bd. XI. Leipzig: Akad. Verlagsges (1937–1939). p. 204, [5].
-
^ Copeland, H. F. (1956). The Classification of Lower Organisms. Palo Alto: Pacific Books, pp. 63-67, [6].
-
^ Ettl, H., 1978. Xanthophyceae. In: Ettl, H., Gerloff, J., Heynig, H. (Eds.), Süsswasserflora von Mitteleuropa, Bd. 3. 1. Teil. Gustav Fischer Verlag, Stuttgart, pp. 1–530.
-
^ Negrisolo, E.; et al. (2004). "Morphological convergence characterizes the evolution of Xanthophyceae (Heterokontophyta): evidence from nuclear SSU rDNA and plastidial rbcL genes". Molecular Phylogenetics and Evolution. 33 (1): 156–170. doi:10.1016/j.ympev.2004.04.016. PMID 15324845.
-
^ a b Adl SM, Simpson AG, Farmer MA, et al. (2005). "The new higher level classification of eukaryotes with emphasis on the taxonomy of protists". The Journal of Eukaryotic Microbiology. 52 (5): 399–451. doi:10.1111/j.1550-7408.2005.00053.x. PMID 16248873.
-
^ Maistro S, Broady PA, Andreoli C, Negrisolo E (August 2009). "Phylogeny and taxonomy of Xanthophyceae (Stramenopiles, Chromalveolata)". Protist. 160 (3): 412–26. doi:10.1016/j.protis.2009.02.002. PMID 19386545.
-
^ Adl SM, Simpson AG, Lane CE, 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.
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