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Raphidophyte

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A class of aquatic algae

The Raphidophyceae (raphidophytes, formerly referred to as Chloromonadophyceae and Chloromonadineae)[1] are a small group of eukaryotic algae that includes both marine and freshwater species.[2] All raphidophytes are unicellular, with large cells (50 to 100 μm), but no cell walls. Raphidophytes possess a pair of flagella, organised such that both originate from the same invagination (or gullet). One flagellum points forwards,and is covered in hair-like mastigonemes, while the other points backwards across the cell surface, lying within a ventral groove. Raphidophytes contain numerous ellipsoid chloroplasts, which contain chlorophylls a, c1 and c2. They also make use of accessory pigments including β-carotene and diadinoxanthin. Unlike other heterokontophytes, raphidophytes do not possess the photoreceptive organelle (or eyespot) typical of this group.

In terms of ecology, raphidophytes occur as photosynthetic autotrophs across a range of aquatic systems. Freshwater species are more common in acidic waters, such as pools in bogs. Marine species often produce large blooms in summer, particularly in coastal waters. Off the Japanese coast, the resulting red tides often cause disruption to fish farms, although raphidophytes are not usually responsible for toxic blooms.

The position of this group varied in former classifications. Some protozoologists treated the chloromonads as an order within the phytoflagellates.[3] Some phycologists classified them with the Xanthophyceae and the Eustigmatophyceae in the division Xanthophyta.[4] Others considered them as related to the Chrysophyceae, Dinophyceae, or Cryptophyceae [5]

Recently, the helizoan Actinophyrida was moved to the group.

Taxonomy

Classification based on Cavalier-Smith and Scoble 2013[6][7]

References

  1. ^ Herbert Graffius, J. (1966). "Additions to Our Knowledge of Michigan Pyrrhophyta and Chloromonadophyta". Transactions of the American Microscopical Society. 85 (2): 260–270. doi:10.2307/3224637. JSTOR 3224637..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"""""'"'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
  2. ^ Hoek, C. van den, Mann, D. G. and Jahns, H. M. (1995). Algae : An introduction to phycology. UK: Cambridge University Press. ISBN 978-0-521-31687-3.CS1 maint: Uses authors parameter (link)
  3. ^ "RAPHIDIOPHYTA". susqu.edu.
  4. ^ American Water Works Association (2010). Algae: Source to Treatment. p. 281. ISBN 978-1-61300-116-5.
  5. ^ Potter, D; Saunders, G; Andersen, R (1997). "Phylogenetic relationships of the Raphidophyceae and Xanthophyceae as inferred from nucleotide sequences of the 18S ribosomal RNA gene". American Journal of Botany. 84 (7): 966. doi:10.2307/2446287. JSTOR 2446287. PMID 21708651.
  6. ^ Cavalier-Smith, T; Scoble, J. M. (2013). "Phylogeny of Heterokonta: Incisomonas marina, a uniciliate gliding opalozoan related to Solenicola (Nanomonadea), and evidence that Actinophryida evolved from raphidophytes". European Journal of Protistology. 49 (3): 328–353. doi:10.1016/j.ejop.2012.09.002. PMID 23219323.
  7. ^ Guiry, M.D.; Guiry, G.M. (2016). "Raphidophyceae". AlgaeBase (3). Retrieved 2016-08-26.
Eukaryota: SAR: Heterokonta or Stramenopiles
Ochrophyta
(mostly
photosynthetic)PhaeistaHypogyristea Dictyochophyceae/
Actinochrysophyceae/
Axodines
ChrysistaChrysophyceae,
golden algae
Eustigmatophyceae Phaeophyceae,
brown algae
Phaeothamniophyceae Raphidophyceae Synurophyceae Xanthophyceae,
yellow-green algae
KhakistaBolidophyceae Bacillariophyta,
diatoms
Coscinodiscophyceae Bacillariophyceae FragilariophyceaeHeterotrophic
groupsPseudofungi Bigyra Sagenista Opalinata/Slopalinida
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Raphidophyte: Brief Summary

provided by wikipedia EN
A class of aquatic algae

The Raphidophyceae (raphidophytes, formerly referred to as Chloromonadophyceae and Chloromonadineae) are a small group of eukaryotic algae that includes both marine and freshwater species. All raphidophytes are unicellular, with large cells (50 to 100 μm), but no cell walls. Raphidophytes possess a pair of flagella, organised such that both originate from the same invagination (or gullet). One flagellum points forwards,and is covered in hair-like mastigonemes, while the other points backwards across the cell surface, lying within a ventral groove. Raphidophytes contain numerous ellipsoid chloroplasts, which contain chlorophylls a, c1 and c2. They also make use of accessory pigments including β-carotene and diadinoxanthin. Unlike other heterokontophytes, raphidophytes do not possess the photoreceptive organelle (or eyespot) typical of this group.

In terms of ecology, raphidophytes occur as photosynthetic autotrophs across a range of aquatic systems. Freshwater species are more common in acidic waters, such as pools in bogs. Marine species often produce large blooms in summer, particularly in coastal waters. Off the Japanese coast, the resulting red tides often cause disruption to fish farms, although raphidophytes are not usually responsible for toxic blooms.

The position of this group varied in former classifications. Some protozoologists treated the chloromonads as an order within the phytoflagellates. Some phycologists classified them with the Xanthophyceae and the Eustigmatophyceae in the division Xanthophyta. Others considered them as related to the Chrysophyceae, Dinophyceae, or Cryptophyceae

Recently, the helizoan Actinophyrida was moved to the group.

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cc-by-sa-3.0
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visit source
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wikipedia EN