The haptophytes, classified either as the Haptophyta, Haptophytina or Prymnesiophyta (named for ''
Prymnesium
''Prymnesium'' is a genus of haptophytes, including the species '' Prymnesium parvum''.
The genus is a unicellular motile alga. It is ellipsoidal in shape one flagellum is straight and there are two longer ones which enable movement.
The name La ...
''), are a
clade of
algae.
The names Haptophyceae or Prymnesiophyceae are sometimes used instead.
This ending implies classification at the
class
Class or The Class may refer to:
Common uses not otherwise categorized
* Class (biology), a taxonomic rank
* Class (knowledge representation), a collection of individuals or objects
* Class (philosophy), an analytical concept used differentl ...
rank
Rank is the relative position, value, worth, complexity, power, importance, authority, level, etc. of a person or object within a ranking, such as:
Level or position in a hierarchical organization
* Academic rank
* Diplomatic rank
* Hierarchy
* ...
rather than as a division. Although the
phylogenetics
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups ...
of this group has become much better understood in recent years, there remains some dispute over which rank is most appropriate.
Characteristics
![Haptophyta cell scheme](https://upload.wikimedia.org/wikipedia/commons/7/74/Haptophyta_cell_scheme.svg)
The
chloroplasts are pigmented similarly to those of the
heterokont
Heterokonts are a group of protists (formally referred to as Heterokonta, Heterokontae or Heterokontophyta). The group is a major line of eukaryotes. Most are algae, ranging from the giant multicellular kelp to the unicellular diatoms, which a ...
s, 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 algal
Red algae, or Rhodophyta (, ; ), are one of the oldest groups of eukaryotic algae. The Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority ...
endosymbionts.
The cells typically have two slightly unequal
flagella, both of which are smooth, and a unique organelle called a ''
haptonema
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. This ending implies classification at ...
'', which is superficially similar to a flagellum but differs in the arrangement of
microtubules and in its use. The name comes from the
Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
''hapsis'', touch, and ''nema'', round thread. The
mitochondria have tubular
cristae.
Significance
The best-known haptophytes are
coccolithophore
Coccolithophores, or coccolithophorids, are single celled organisms which are part of the phytoplankton, the autotrophic (self-feeding) component of the plankton community. They form a group of about 200 species, and belong either to the king ...
s, which make up 673 of the 762 described haptophyte species, and have an exoskeleton of calcareous plates called
coccolith
Coccoliths are individual plates or scales of calcium carbonate formed by coccolithophores (single-celled phytoplankton such as '' Emiliania huxleyi'') and cover the cell surface arranged in the form of a spherical shell, called a ''coccosphere' ...
s. Coccolithophores are some of the most abundant marine
phytoplankton, especially in the open ocean, and are extremely abundant as microfossils, forming
chalk
Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor. Ch ...
deposits. Other planktonic haptophytes of note include ''
Chrysochromulina
''Chrysochromulina'' is a genus of haptophytes. This phytoplankton is distributed globally in brackish and marine waters across approximately 60 known species. All ''Chrysochromulina'' species are phototrophic, however some have been shown to ...
'' and ''
Prymnesium
''Prymnesium'' is a genus of haptophytes, including the species '' Prymnesium parvum''.
The genus is a unicellular motile alga. It is ellipsoidal in shape one flagellum is straight and there are two longer ones which enable movement.
The name La ...
'', which periodically form toxic marine
algal bloom
An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in freshwater or marine water systems. It is often recognized by the discoloration in the water from the algae's pigments. The term ''algae'' encompass ...
s, and ''
Phaeocystis
''Phaeocystis'' is a genus of algae belonging to the Prymnesiophyte class and to the larger division of Haptophyta. It is a widespread marine phytoplankton and can function at a wide range of temperatures ( eurythermal) and salinities (euryhali ...
'', blooms of which can produce unpleasant foam which often accumulates on beaches.
[
Haptophytes are economically important, as species such as '' Pavlova lutheri'' and '' Isochrysis sp.'' are widely used in the aquaculture industry to feed ]oyster
Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but not ...
and shrimp larvae. They contain a large amount of polyunsaturated fatty acid
Polyunsaturated fatty acids (PUFAs) are fatty acids that contain more than one double bond in their backbone. This class includes many important compounds, such as essential fatty acids and those that give drying oils their characteristic proper ...
s such as docosahexaenoic acid
Docosahexaenoic acid (DHA) is an omega-3 fatty acid that is a primary structural component of the human brain, cerebral cortex, skin, and retina. In physiological literature, it is given the name 22:6(n-3). It can be synthesized from alpha-lin ...
(DHA), stearidonic acid
Stearidonic acid (SDA: C18 H28 O2; 18: 4, n-3) is an ω-3 fatty acid, sometimes called moroctic acid. It is biosynthesized from alpha-linolenic acid (ALA: C18H30O2; 18:3, n-3) by the enzyme delta-6-desaturase, that removes two hydrogen (H) ato ...
and alpha-linolenic acid
''alpha''-Linolenic acid (ALA), also known as α-Linolenic acid (from Greek ''alpha'' meaning "first" and ''linon'' meaning flax), is an ''n''−3, or omega-3, essential fatty acid. ALA is found in many seeds and oils, including flaxseed, wa ...
. ''Tisochrysis lutea'' contains betain lipids and phospholipids.
Classification
The haptophytes were first placed in the class Chrysophyceae
The Chrysophyceae, usually called chrysophytes, chrysomonads, golden-brown algae or golden algae are a large group of algae, found mostly in freshwater. Golden algae is also commonly used to refer to a single species, '' Prymnesium parvum'', whic ...
(golden algae), but ultrastructural data have provided evidence to classify them separately. 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.
Haptophytes was discussed to be closely related to cryptomonad
The cryptomonads (or cryptophytes) are a group of algae, most of which have plastids. They are common in freshwater, and also occur in marine and brackish habitats. Each cell is around 10–50 μm in size and flattened in shape, with an anteri ...
s.
Haptophytes are closely related to the SAR
SAR or Sar may refer to:
Places
* Sar (river), Galicia, Spain
* Sar, Bahrain, a residential district
* Sar, Iran (disambiguation), several places in Iran
* Sar, Tibet, Tibet Autonomous Region of China
* Šar Mountains, in southeastern Europe
...
clade.
Subphylum Haptophytina Cavalier-Smith 2015 Hibberd 1976 sensu Ruggerio et al. 2015">aptophyta Hibberd 1976 sensu Ruggerio et al. 2015ref>
* Clade
Rappemonada Kim et al. 2011
** Class
Rappephyceae
Rappephyceae, or Rappemonads, are a small family of protists first described in 2011, of uncertain phylogenic affinity. It has been discussed as a possible member of a larger clade Haptophyta. This newly identified taxonomic class of phytoplankton ...
Cavalier-Smith 2015
*** Order
Rappemonadales
**** Family
Rappemonadaceae
* Clade
Haptomonada (Margulis & Schwartz 1998) [Haptophyta Hibberd 1976 emend. Edvardsen & Eikrem 2000; Prymnesiophyta
Green & Jordan, 1994; Prymnesiomonada; Prymnesiida Hibberd 1976; Haptophyceae Christensen 1962 ex Silva 1980; Haptomonadida; Patelliferea Cavalier-Smith 1993]
** Class Pavlovophyceae
Cavalier-Smith 1986 [Pavlovophycidae
Cavalier-Smith 1986]
*** Order Pavlovales
Green 1976
**** Family Pavlovaceae
Green 1976
** Class
Prymnesiophyceae
Prymnesiophyceae is a haptophyte class. Although it was originally described by Casper in 1972, it did not receive a Latin diagnosis (a requirement for valid publication under the International Code of Botanical Nomenclature
The ''Internatio ...
Christensen 1962 emend. Cavalier-Smith 1996 Cavalier-Smith 1986; Coccolithophyceae Casper 1972 ex Rothmaler 1951">aptophyceae s.s.; Prymnesiophycidae Cavalier-Smith 1986; Coccolithophyceae Casper 1972 ex Rothmaler 1951*** Family †
Eoconusphaeraceae Kristan-Tollmann 1988 onusphaeraceae*** Family †
Goniolithaceae Deflandre 1957
*** Family †
Lapideacassaceae Black, 1971
*** Family †
Microrhabdulaceae Deflandre 1963
*** Family †
Nannoconaceae Deflandre 1959
*** Family †
Polycyclolithaceae Forchheimer 1972 emend Varol, 1992
*** Family †
Lithostromationaceae Deflandre 1959
*** Family †
Rhomboasteraceae Bown, 2005
*** Family
Braarudosphaeraceae Deflandre 1947
*** Family
Ceratolithaceae Norris 1965 emend Young & Bown 2014 Lipps 1969 - cf Young & Bown 2014">riquetrorhabdulaceae Lipps 1969 - cf Young & Bown 2014*** Family
Alisphaeraceae Young et al., 2003
*** Family
Papposphaeraceae Jordan & Young 1990 emend Andruleit & Young 2010
*** Family
Umbellosphaeraceae Young et al., 2003 mbellosphaeroideae*** Order †
Discoasterales Hay 1977
**** Family †
Discoasteraceae Tan 1927
**** Family †
Heliolithaceae Hay & Mohler 1967
**** Family †
Sphenolithaceae Deflandre 1952
**** Family †
Fasciculithaceae Hay & Mohler 1967
*** Order
Phaeocystales Medlin 2000
**** Family
Phaeocystaceae Lagerheim 1896
*** Order
Prymnesiales Papenfuss 1955 emend. Edvardsen and Eikrem 2000
**** Family
Chrysochromulinaceae Edvardsen, Eikrem & Medlin 2011
**** Family
Prymnesiaceae
Prymnesiaceae is a family of algae in the clade Haptophyta. It contains toxic microalgae such as ''Prymnesium''.
Genera
* '' Apistonema''
* '' Chrysocampanula''
* '' Chrysoculter''
* '' Corymbellus''
* '' Haptolina''
* '' Hyalolithus''
* '' Ima ...
Conrad 1926 ex Schmidt 1931
*** Subclass
Calcihaptophycidae
**** Order
Isochrysidales
Isochrysidales is an order of Haptophyceae
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 i ...
Pascher 1910 Young & Bown 1997">rinsiales Young & Bown 1997***** Family †
Prinsiaceae Hay & Mohler 1967 emend. Young & Bown, 1997
***** Family
Isochrysidaceae Parke 1949 Hay 1977">hrysotilaceae; Marthasteraceae Hay 1977***** Family
Noëlaerhabdaceae Jerkovic 1970 emend. Young & Bown, 1997 Black 1971">ephyrocapsaceae Black 1971**** Order †
Eiffellithales Rood, Hay & Barnard 1971 (loxolith; imbricating murolith)
***** Family †
Chiastozygaceae Rood, Hay & Barnard 1973 Reinhardt, 1965">hmuellerellaceae Reinhardt, 1965***** Family †
Eiffellithaceae Reinhardt 1965
***** Family †
Rhagodiscaceae Hay 1977
**** Order
Stephanolithiales Bown & Young 1997 (protolith; non-imbrication murolith)
***** Family
Parhabdolithaceae Bown 1987
***** Family †
Stephanolithiaceae Black 1968 emend. Black 1973
**** Order
Zygodiscales Young & Bown 1997 repidolithales***** Family
Helicosphaeraceae Black 1971
***** Family
Pontosphaeraceae Lemmermann 1908
***** Family †
Zygodiscaceae Hay & Mohler 1967
**** Order
Syracosphaerales Ostenfeld 1899 emend. Young et al., 2003 Ostenfeld 1899">habdosphaerales Ostenfeld 1899***** Family
Calciosoleniaceae Kamptner 1927
***** Family
Syracosphaeraceae Lohmann, 1902 Kamptner 1928">alopappiaceae Kamptner 1928(caneolith & cyrtolith; murolith)
***** Family
Rhabdosphaeraceae Haeckel, 1894 (planolith)
**** Order †
Watznaueriales Bown 1987 (imbricating placolith)
***** Family †
Watznaueriaceae Rood, Hay & Barnard 1971
**** Order †
Arkhangelskiales Bown & Hampton 1997
***** Family †
Arkhangelskiellaceae Bukry 1969
***** Family †
Kamptneriaceae Bown & Hampton 1997
**** Order †
Podorhabdales Rood 1971 Aubry 2009; Prediscosphaerales Aubry 2009">iscutales Aubry 2009; Prediscosphaerales Aubry 2009(non-imbricating or radial placolith)
***** Family †
Axopodorhabdaceae Wind & Wise 1977 Noel 1965">odorhabdaceae Noel 1965***** Family †
Biscutaceae Black, 1971
***** Family †
Calyculaceae Noel 1973
***** Family †
Cretarhabdaceae Thierstein 1973
***** Family †
Mazaganellaceae Bown 1987
***** Family †
Prediscosphaeraceae Rood et al., 1971 Black 1968">eflandriaceae Black 1968***** Family †
Tubodiscaceae Bown & Rutledge 1997
**** Order
Coccolithales
Coccolithales is an order of Haptophyceae. The Coccolithales has long been considered one of only two orders in the Coccolithophyceae, the other order being the Isochrysidales
Isochrysidales is an order of Haptophyceae
The haptophytes, cla ...
Schwartz 1932 occolithophorales***** Family
Reticulosphaeraceae Cavalier-Smith 1996 eticulosphaeridae***** Family
Calcidiscaceae Young & Bown 1997
***** Family
Coccolithaceae Poche 1913 emend. Young & Bown, 1997 occolithophoraceae***** Family
Pleurochrysidaceae Fresnel & Billard 1991
***** Family
Hymenomonadaceae Senn 1900 Schussnig 1930">chrosphaeraceae Schussnig 1930
References
External links
{{Taxonbar, from=Q500531
Algal taxonomy
*
Bikont phyla