The haptophytes, classified either as the Haptophyta, Haptophytina or Prymnesiophyta (named for ''
Prymnesium''), are a
clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English ter ...
of
algae
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular micr ...
.
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 differently ...
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
The
chloroplast
A chloroplast () is a type of membrane-bound organelle known as a plastid that conducts photosynthesis mostly in plant and algal cells. The photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, and stores it i ...
s are pigmented similarly to those of the
heterokonts, 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 endosymbionts.
The cells typically have two slightly unequal
flagella
A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates.
A microorganism may have fro ...
, 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
Microtubules are polymers of tubulin that form part of the cytoskeleton and provide structure and shape to eukaryotic cells. Microtubules can be as long as 50 micrometres, as wide as 23 to 27 nm and have an inner diameter between 1 ...
s and in its use. The name comes from the
Greek ''hapsis'', touch, and ''nema'', round thread. The
mitochondria
A mitochondrion (; ) is an organelle found in the cells of most Eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used ...
have tubular
crista
A crista (; plural cristae) is a fold in the inner membrane of a mitochondrion. The name is from the Latin for ''crest'' or ''plume'', and it gives the inner membrane its characteristic wrinkled shape, providing a large amount of surface area fo ...
e.
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
Phytoplankton () are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems. The name comes from the Greek words (), meaning 'plant', and (), meaning 'wanderer' or 'drifter'.
...
, 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. C ...
deposits. Other planktonic haptophytes of note include ''
Chrysochromulina'' and ''
Prymnesium'', which periodically form toxic marine
algal blooms, and ''
Phaeocystis'', blooms of which can produce unpleasant foam which often accumulates on beaches.
[
Haptophytes are economically important, as species such as '']Pavlova lutheri __NOTOC__
Pavlova may refer to:
Persons
*Pavlova, the feminine form of Pavlov, a common Russian and Bulgarian family name
*Anna Pavlova (1881–1931), Russian ballerina
*Anna Pavlova (born 1987), Russian artistic gymnast
*Karolina Pavlova, Russian ...
'' and ''Isochrysis
''Isochrysis'' is a genus of haptophytes. It includes the species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defin ...
sp.'' are widely used in the aquaculture
Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. lot ...
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
Shrimp are crustaceans (a form of shellfish) with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata of the decapod order, although some crustaceans outside of this order are ref ...
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 and alpha-linolenic acid. ''Tisochrysis lutea'' contains betain lipids and phospholipid
Phospholipids, are a class of lipids whose molecule has a hydrophilic "head" containing a phosphate group and two hydrophobic "tails" derived from fatty acids, joined by an alcohol residue (usually a glycerol molecule). Marine phospholipids typ ...
s.
Classification
The haptophytes were first placed in the class Chrysophyceae (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 cryptomonads.
Haptophytes are closely related to the SAR 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 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 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 Pascher 1910 Young & Bown 1997">rinsiales Young & Bown 1997***** Family †
Prinsiaceae Hay & Mohler 1967 emend. Young & Bown, 1997
***** Family
Isochrysidaceae
Isochrysidaceae is a family of algae in the clade Haptophyta. It contains feedstock microalgae such as ''Isochrysis galbana''.
Genera
*'' Chrysidalis''
*'' Chrysonema''
*'' Dicrateria''
*'' Erkenia''
*''Isochrysis
''Isochrysis'' is a genus ...
Parke 1949 Hay 1977">hrysotilaceae; Marthasteraceae Hay 1977***** Family
Noëlaerhabdaceae
Noelaerhabdaceae is a family of coccolithophorids. Some genera
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification ...
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
Syracosphaerales is an order of algae consisting of three families:
* Calciosoleniaceae
* Rhabdosphaeraceae
Rhabdosphaeraceae is a family of algae
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthesi ...
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
Rhabdosphaeraceae is a family of algae
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthesis, photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinc ...
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.
References
Ha ...
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