Editing Haptophyte

{{Short description|Type of algae}}
{{Automated taxobox
| name = Haptophytes
| image = Coccolithus pelagicus.jpg
| image_caption = [[Coccolithophore]] (''[[Coccolithus pelagicus]]'')
| display_parents = 4
| taxon = Haptophyta
| authority =  Hibberd, 1976 ''stat. nov.'' Cavalier-Smith, 2015<ref name="8phyla">{{cite journal|title=Kingdom Chromista and its eight phyla: a new synthesis emphasising periplastid protein targeting, cytoskeletal and periplastid evolution, and ancient divergences|first1=Thomas|last1=Cavalier-Smith|date=2017|journal=Protoplasma|pages=297–357|volume=255|issue=1 |doi=10.1007/s00709-017-1147-3|pmid=28875267 |pmc=5756292 |s2cid=19939172 |doi-access=free}}</ref>
| subdivision_ranks = Classes & orders
| subdivision = 
* [[Rappephyceae]]
** [[Pavlomulinales]]
* [[Pavlovophyceae]]
** [[Pavlovales]]
* [[Prymnesiophyceae]] ''[[sensu|s.s.]]'' (=[[Coccolithophyceae]])
** †[[Discoasterales]]
** [[Phaeocystales]]
** [[Prymnesiales]]
** [[Isochrysidales]]
** [[Stephanolithiales]]
** [[Coccolithales]]
** †[[Eiffellithales]]
** [[Syracosphaerales]]
** †[[Arkhangelskiales]]
** †[[Podorhabdales]]
| synonyms = 
* Prymnesiophyta <small>Green & Jordan, 1994</small>
* Prymnesiophyceae ''[[sensu|s.l.]]'' <small>Casper, 1972 ex Hibberd, 1976</small>
* Haptophyceae ''s.l.'' <small>Christensen, 1962 ex Silva, 1980</small>
* Haptophyta <small>Hibberd, 1976</small>
}}

The '''haptophytes''', classified either as the '''Haptophyta''', '''Haptophytina''' or '''Prymnesiophyta''' (named for ''[[Prymnesium]]''), are a [[clade]] of [[algae]].

The names '''Haptophyceae''' or '''Prymnesiophyceae''' are sometimes used instead.<ref name="urlwww.ncbi.nlm.nih.gov">{{cite web |url=https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=2830&lvl=2 |title= Haptophyta | work = NCBI taxonomy database | publisher = National Center for Biotechnology Information, U.S. National Library of Medicine }}</ref><ref name="pmid18830665">{{cite journal | vauthors = Satoh M, Iwamoto K, Suzuki I, Shiraiwa Y | title = Cold stress stimulates intracellular calcification by the coccolithophore, Emiliania huxleyi (Haptophyceae) under phosphate-deficient conditions | journal = Marine Biotechnology | volume = 11 | issue = 3 | pages = 327–33 | year = 2009 | pmid = 18830665 | doi = 10.1007/s10126-008-9147-0 | url = https://tsukuba.repo.nii.ac.jp?action=repository_uri&item_id=18688 | hdl-access = free | s2cid = 18014503 | hdl = 2241/104412 }}</ref><ref>{{cite web |url=https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=2136 |title=ITIS Standard Report |access-date=19 July 2014}}</ref> This ending implies classification at the [[class (biology)|class]] [[Taxonomic rank|rank]] rather than as a division. Although the [[phylogenetics]] of this group has become much better understood in recent years, there remains some dispute over which rank is most appropriate.

==Characteristics==
[[File:2023_Haptophyte.jpg|center|thumb|upright=2|{{center|'''Representation of a  haptophyte'''}}{{ordered list|Haptonema, for movement|
Flagellar [[Basal body|basal bodies]]|
[[Flagellum]]|
Surface scale|
Alveolae, surface cavities or pits|
[[Mitochondria|Mitochondrion]], creates [[Adenosine triphosphate|ATP]] (energy) for the cell|
[[Golgi apparatus]], modifies [[protein]]s and sends them out of the cell|
Nascent scales|
[[Endoplasmic reticulum]], the transport network for molecules going to specific parts of the cell|
Plastidial endoplasmic reticulum|
Periplastidial membrane|
Outer and inner [[plastid]] membranes|
[[Thylakoid]], site of the [[light-dependent reactions]] of [[photosynthesis]]|
[[Pyrenoid]], center of [[carbon fixation]]|
[[Cell nucleus|Nucleus]]|
[[Lysosome]], holds enzymes|
[[Phagosome|Phagocytic vacuole]] with prey}}]]

The [[chloroplast]]s are pigmented similarly to those of the [[heterokont]]s,<ref>{{cite journal | vauthors = Andersen RA | title = Biology and systematics of heterokont and haptophyte algae | journal = American Journal of Botany | volume = 91 | issue = 10 | pages = 1508–22 | date = October 2004 | pmid = 21652306 | doi = 10.3732/ajb.91.10.1508 }}</ref> but the structure of the rest of the cell is different, so it may be that they are a separate line whose chloroplasts are derived from similar [[red algae|red algal]] endosymbionts. Haptophyte chloroplasts contain chlorophylls [[Chlorophyll a|a]], [[Chlorophyll_c#Chlorophyll_c1|c<sub>1</sub>]], and [[Chlorophyll_c#Chlorophyll_c2|c<sub>2</sub>]] but lack chlorophyll [[Chlorophyll_b|b]]. For carotenoids, they have [[beta-carotene|beta-]], [[Α-Carotene|alpha-]], and [[γ-Carotene|gamma-]] carotenes. Like [[diatoms]] and [[brown algae]], they have also [[fucoxanthin]], an oxidized isoprenoid derivative that is likely the most important driver of their brownish-yellow color.<ref name="l415">{{cite book | last=Margulis | first=L. | last2=Chapman | first2=M.J. | title=Kingdoms and Domains: An Illustrated Guide to the Phyla of Life on Earth | chapter=Pr-25 Haptomonada | publisher=Academic Press | year=2009 | isbn=978-0-08-092014-6 | url=https://books.google.com/books?id=9IWaqAOGyt4C | access-date=2024-11-12 | page=}}</ref>

The cells typically have two slightly unequal [[flagellum|flagella]], both of which are smooth, and a unique organelle called a '''haptonema''', which is superficially similar to a flagellum but differs in the arrangement of [[microtubule]]s and in its use.  The name comes from the [[Greek language|Greek]] ''hapsis'', touch, and ''nema'', round thread.  The [[mitochondrion|mitochondria]] have tubular [[crista]]e.

Most haptophytes reportedly produce [[chrysolaminarin]] rather than [[starch]] as their major storage polysaccharide, but some [[Pavlovaceae]] produce [[paramylon]].<ref name="d311">{{cite book | last=Tsuji | first=Yoshinori | last2=Yoshida | first2=Masaki | title=Advances in Botanical Research | chapter=Biology of Haptophytes: Complicated Cellular Processes Driving the Global Carbon Cycle | publisher=Elsevier | volume=84 | date=2017 | isbn=978-0-12-802651-9 | doi=10.1016/bs.abr.2017.07.002 | page=219–261}}</ref><ref name="x389">{{cite journal | last=Penot | first=Mathias | last2=Dacks | first2=Joel B. | last3=Read | first3=Betsy | last4=Dorrell | first4=Richard G. | title=Genomic and meta-genomic insights into the functions, diversity and global distribution of haptophyte algae | journal=Applied Phycology | volume=3 | issue=1 | date=2022-12-31 | issn=2638-8081 | doi=10.1080/26388081.2022.2103732 | doi-access=free | pages=340–359}}</ref> The chain length of the chrysolaminarin is reportedly short (polymers of 20–50 glycosides, unlike the 300+ of comparable [[amylose]]), and it is located in cytoplasmic membrane-bound vacuoles.<ref name="x389">{{cite journal | last=Penot | first=Mathias | last2=Dacks | first2=Joel B. | last3=Read | first3=Betsy | last4=Dorrell | first4=Richard G. | title=Genomic and meta-genomic insights into the functions, diversity and global distribution of haptophyte algae | journal=Applied Phycology | volume=3 | issue=1 | date=2022-12-31 | issn=2638-8081 | doi=10.1080/26388081.2022.2103732 | doi-access=free | pages=340–359}}</ref>

==Significance==

The best-known haptophytes are [[coccolithophore]]s, which make up 673 of the 762 described haptophyte species,<ref>{{cite web | url = https://www.algaebase.org/pub_taxonomy/?id=97244 | title = Haptophyta | work = Algaebase | access-date = 2019-10-27 | archive-date = 2021-02-18 | archive-url = https://web.archive.org/web/20210218200436/https://www.algaebase.org/pub_taxonomy/?id=97244 | url-status = dead }}</ref> and have an exoskeleton of calcareous plates called [[coccolith]]s. Coccolithophores are some of the most abundant marine [[phytoplankton]], especially in the open ocean, and are extremely abundant as microfossils, forming [[chalk]] deposits.  Other planktonic haptophytes of note include ''[[Chrysochromulina]]'' and ''[[Prymnesium]]'', which periodically form toxic marine [[algal bloom]]s, and ''[[Phaeocystis]]'', blooms of which can produce unpleasant foam which often accumulates on beaches.<ref name=Cuvelier/>

Haptophytes are economically important, as species such as ''[[Pavlova (algae)|Pavlova lutheri]]'' and ''[[Isochrysis]] sp.'' are widely used in the [[aquaculture]] industry to feed [[oyster]] and [[shrimp]] larvae. They contain a large amount of [[polyunsaturated fatty acid]]s such as [[docosahexaenoic acid]] (DHA), [[stearidonic acid]] and [[alpha-linolenic acid]].<ref>{{cite journal | vauthors = Renaud SM, Zhou HC, Parry DL, Thinh LV, Woo KC |doi=10.1007/BF00003948 |title=Effect of temperature on the growth, total lipid content and fatty acid composition of recently isolated tropical microalgae Isochrysis sp., Nitzschia closterium, Nitzschia paleacea, and commercial species Isochrysis sp. (clone T.ISO) |journal=Journal of Applied Phycology |volume=7 |issue=6 |pages=595–602 |year=1995 |s2cid=206766536 }}</ref> ''Tisochrysis lutea'' contains betain lipids and [[phospholipid]]s.<ref>{{cite journal | vauthors = Kato M, Sakai M, Adachi K, Ikemoto H, Sano H |doi=10.1016/0031-9422(96)00115-X |title=Distribution of betaine lipids in marine algae |journal=Phytochemistry |volume=42 |issue=5 |pages=1341–5 |year=1996 }}</ref>

==Classification==
{{Further|Wikispecies:Haptophyta}}
The haptophytes were first placed in the class [[Chrysophyceae]] (golden algae), but ultrastructural data have provided evidence to classify them separately.<ref>{{cite book | doi=10.1007/978-3-7091-6542-3_11 |volume = 11| pages=187–219 | year=1997 | vauthors = Medlin LK | title=Origins of Algae and their Plastids | chapter=Phylogenetic relationships of the 'golden algae' (Haptophytes, heterokont chromophytes) and their plastids | series=Plant Systematics and Evolution |isbn = 978-3-211-83035-2| url=http://epic.awi.de/2100/1/Med1997c.pdf |archive-url=https://web.archive.org/web/20120317051946/http://epic.awi.de/2100/1/Med1997c.pdf |archive-date=2012-03-17 |url-status=live }}</ref> Both molecular and morphological evidence supports their division into five orders; coccolithophores make up the Isochrysidales and Coccolithales. Very small (2-3μm) uncultured pico-prymnesiophytes are ecologically important.<ref name=Cuvelier>{{cite journal | vauthors = Cuvelier ML, Allen AE, Monier A, McCrow JP, Messié M, Tringe SG, Woyke T, Welsh RM, Ishoey T, Lee JH, Binder BJ, DuPont CL, Latasa M, Guigand C, Buck KR, Hilton J, Thiagarajan M, Caler E, Read B, Lasken RS, Chavez FP, Worden AZ | display-authors = 6 | title = Targeted metagenomics and ecology of globally important uncultured eukaryotic phytoplankton | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 107 | issue = 33 | pages = 14679–84 | date = August 2010 | pmid = 20668244 | pmc = 2930470 | doi = 10.1073/pnas.1001665107 | bibcode = 2010PNAS..10714679C | doi-access = free }}</ref>

Haptophytes was discussed to be closely related to [[cryptomonad]]s.<ref name="pmid19398025">{{cite journal | vauthors = Reeb VC, Peglar MT, Yoon HS, Bai JR, Wu M, Shiu P, Grafenberg JL, Reyes-Prieto A, Rümmele SE, Gross J, Bhattacharya D | display-authors = 6 | title = Interrelationships of chromalveolates within a broadly sampled tree of photosynthetic protists | journal = Molecular Phylogenetics and Evolution | volume = 53 | issue = 1 | pages = 202–11 | date = October 2009 | pmid = 19398025 | doi = 10.1016/j.ympev.2009.04.012 }}</ref>

Haptophytes are closely related to the [[SAR supergroup|SAR]] clade.<ref name="pmid21810989">{{cite journal | vauthors = Parfrey LW, Lahr DJ, Knoll AH, Katz LA | title = Estimating the timing of early eukaryotic diversification with multigene molecular clocks | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 108 | issue = 33 | pages = 13624–9 | date = August 2011 | pmid = 21810989 | pmc = 3158185 | doi = 10.1073/pnas.1110633108 | bibcode = 2011PNAS..10813624P | doi-access = free }}</ref>

Subphylum Haptophytina <small>Cavalier-Smith 2015</small> [Haptophyta <small>Hibberd 1976 sensu Ruggerio et al. 2015</small>]<ref>{{citation | vauthors = Guiry MD |date=2016| title =AlgaeBase |publisher=World-wide electronic publication, National University of Ireland, Galway| url=http://www.algaebase.org/browse/taxonomy/?id=97244 |access-date=25 October 2016}}</ref>
* Clade [[Rappemonada]] <small>Kim et al. 2011</small>
** Class [[Rappephyceae]] <small>Cavalier-Smith 2015</small>
*** Order [[Rappemonadales]]
**** Family [[Rappemonadaceae]]
* Clade [[Haptomonada]] <small>(Margulis & Schwartz 1998)</small> [Haptophyta Hibberd 1976 emend. Edvardsen & Eikrem 2000; Prymnesiophyta <small>Green & Jordan, 1994</small>; Prymnesiomonada; Prymnesiida Hibberd 1976; Haptophyceae Christensen 1962 ex Silva 1980; Haptomonadida; Patelliferea Cavalier-Smith 1993]
** Class [[Pavlovophyceae]] <small>Cavalier-Smith 1986</small> [Pavlovophycidae <small>Cavalier-Smith 1986</small>]
*** Order [[Pavlovales]] <small>Green 1976</small>
**** Family [[Pavlovaceae]] <small>Green 1976</small>
** Class [[Prymnesiophyceae]] <small>Christensen 1962 emend. Cavalier-Smith 1996</small> [Haptophyceae s.s.; Prymnesiophycidae <small>Cavalier-Smith 1986</small>; Coccolithophyceae <small>Casper 1972 ex Rothmaler 1951</small>]
*** Family †[[Eoconusphaeraceae]] <small>Kristan-Tollmann 1988</small> [Conusphaeraceae]
*** Family †[[Goniolithaceae]] <small>Deflandre 1957</small>
*** Family †[[Lapideacassaceae]] <small>Black, 1971</small>
*** Family †[[Microrhabdulaceae]] <small>Deflandre 1963</small>
*** Family †[[Nannoconaceae]] <small>Deflandre 1959</small>
*** Family †[[Polycyclolithaceae]] <small>Forchheimer 1972 emend Varol, 1992</small>
*** Family †[[Lithostromationaceae]] <small>Deflandre 1959</small>
*** Family †[[Rhomboasteraceae]] <small>Bown, 2005</small>
*** Family [[Braarudosphaeraceae]] <small>Deflandre 1947</small>
*** Family [[Ceratolithaceae]] <small>Norris 1965 emend Young & Bown 2014</small> [Triquetrorhabdulaceae <small>Lipps 1969 - cf Young & Bown 2014</small>]
*** Family [[Alisphaeraceae]] <small>Young et al., 2003</small>
*** Family [[Papposphaeraceae]] <small>Jordan & Young 1990 emend Andruleit & Young 2010</small>
*** Family [[Umbellosphaeraceae]] <small>Young et al., 2003</small> [Umbellosphaeroideae]
*** Order †[[Discoasterales]] <small>Hay 1977</small>
**** Family †[[Discoasteraceae]] <small>Tan 1927</small>
**** Family †[[Heliolithaceae]] <small>Hay & Mohler 1967</small>
**** Family †[[Sphenolithaceae]] <small>Deflandre 1952</small>
**** Family †[[Fasciculithaceae]] <small>Hay & Mohler 1967</small>
*** Order [[Phaeocystales]] <small>Medlin 2000</small>
**** Family [[Phaeocystaceae]] <small>Lagerheim 1896</small>
*** Order [[Prymnesiales]] <small>Papenfuss 1955 emend. Edvardsen and Eikrem 2000</small>
**** Family [[Chrysochromulinaceae]] <small>Edvardsen, Eikrem & Medlin 2011</small>
**** Family [[Prymnesiaceae]] <small>Conrad 1926 ex Schmidt 1931</small>
*** Subclass [[Calcihaptophycidae]]
**** Order [[Isochrysidales]] <small>Pascher 1910</small> [Prinsiales <small>Young & Bown 1997</small>]
***** Family †[[Prinsiaceae]] <small>Hay & Mohler 1967 emend. Young & Bown, 1997</small>
***** Family [[Isochrysidaceae]] <small>Parke 1949</small> [Chrysotilaceae; Marthasteraceae <small>Hay 1977</small>]
***** Family [[Noëlaerhabdaceae]] <small>Jerkovic 1970 emend. Young & Bown, 1997</small> [Gephyrocapsaceae <small>Black 1971</small>]
**** Order †[[Eiffellithales]] <small>Rood, Hay & Barnard 1971</small> (loxolith; imbricating murolith)
***** Family †[[Chiastozygaceae]] <small>Rood, Hay & Barnard 1973</small> [Ahmuellerellaceae <small>Reinhardt, 1965</small>]
***** Family †[[Eiffellithaceae]] <small>Reinhardt 1965</small>
***** Family †[[Rhagodiscaceae]] <small>Hay 1977</small>
**** Order [[Stephanolithiales]] <small>Bown & Young 1997</small> (protolith; non-imbrication murolith)
***** Family [[Parhabdolithaceae]] <small>Bown 1987</small>
***** Family †[[Stephanolithiaceae]] <small>Black 1968 emend. Black 1973</small>
**** Order [[Zygodiscales]] <small>Young & Bown 1997</small> [Crepidolithales]
***** Family [[Helicosphaeraceae]] <small>Black 1971</small>
***** Family [[Pontosphaeraceae]] <small>Lemmermann 1908</small>
***** Family †[[Zygodiscaceae]] <small>Hay & Mohler 1967</small>
**** Order [[Syracosphaerales]] <small>Ostenfeld 1899 emend. Young et al., 2003</small> [Rhabdosphaerales <small>Ostenfeld 1899</small>]
***** Family [[Calciosoleniaceae]] <small>Kamptner 1927</small>
***** Family [[Syracosphaeraceae]] <small>Lohmann, 1902</small> [Halopappiaceae <small>Kamptner 1928</small>] (caneolith & cyrtolith; murolith)
***** Family [[Rhabdosphaeraceae]] <small>Haeckel, 1894</small> (planolith)
**** Order †[[Watznaueriales]] <small>Bown 1987</small> (imbricating placolith)
***** Family †[[Watznaueriaceae]] <small>Rood, Hay & Barnard 1971</small>
**** Order †[[Arkhangelskiales]] <small>Bown & Hampton 1997</small>
***** Family †[[Arkhangelskiellaceae]] <small>Bukry 1969</small>
***** Family †[[Kamptneriaceae]] <small>Bown & Hampton 1997</small>
**** Order †[[Podorhabdales]] <small>Rood 1971</small> [Biscutales <small>Aubry 2009</small>; Prediscosphaerales  <small>Aubry 2009</small>] (non-imbricating or radial placolith)
***** Family †[[Axopodorhabdaceae]] <small>Wind & Wise 1977</small> [Podorhabdaceae <small>Noel 1965</small>]
***** Family †[[Biscutaceae]] <small>Black, 1971</small>
***** Family †[[Calyculaceae]] <small>Noel 1973</small>
***** Family †[[Cretarhabdaceae]] <small>Thierstein 1973</small>
***** Family †[[Mazaganellaceae]] <small>Bown 1987</small>
***** Family †[[Prediscosphaeraceae]] <small>Rood et al., 1971</small> [Deflandriaceae <small>Black 1968</small>]
***** Family †[[Tubodiscaceae]] <small>Bown & Rutledge 1997</small>
**** Order [[Coccolithales]] <small>Schwartz 1932</small> [Coccolithophorales]
***** Family [[Reticulosphaeraceae]] <small>Cavalier-Smith 1996</small> [Reticulosphaeridae]
***** Family [[Calcidiscaceae]] <small>Young & Bown 1997</small>
***** Family [[Coccolithaceae]] <small>Poche 1913 emend. Young & Bown, 1997</small> [Coccolithophoraceae]
***** Family [[Pleurochrysidaceae]] <small>Fresnel & Billard 1991</small>
***** Family [[Hymenomonadaceae]] <small>Senn 1900</small> [Ochrosphaeraceae <small>Schussnig 1930</small>]

== References ==
{{Reflist|30em}}

== External links ==
{{Commons category|Haptophyta}}
{{Wikispecies|Haptophyta}}

{{Life on Earth}}
{{Eukaryota|D.}}
{{Cryptophyta and haptophyta}}
{{Taxonbar|from=Q500531}}

[[Category:Algal taxonomy]]
[[Category:Haptophytes|*]]