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 ...
of
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 ...
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 mic ...
.It is the
sister group
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree.
Definition
The expression is most easily illustrated by a cladogram:
Taxon A and t ...
of the
axodine
The axodines are a group of unicellular stramenopiles that includes silicoflagellate and rhizochromulinid algae, actinomonad heterotrophic flagellates and actinophryid heliozoa. Alternative classifications treat the dictyochophytes as heterokont ...
s. Together, they form the class
Dictyochophyceae
Dictyochophyceae sensu lato is a photosynthetic lineage of heterokont algae.
Taxonomy
* Class Dictyochophyceae Silva 1980 s.l.
** Subclass Sulcophycidae Cavalier-Smith 2013
*** Order Olisthodiscales Cavalier-Smith 2013
**** Family Olisthodiscac ...
.
All known species are marine. They can be single-celled ( coccoid or
flagellate
A flagellate is a cell or organism with one or more whip-like appendages called flagella. The word ''flagellate'' also describes a particular construction (or level of organization) characteristic of many prokaryotes and eukaryotes and their ...
), palmelloid or filamentous. Some members (''
Pelagomonas
''Pelagomonas'' is a genus of heterokont algae. It is a monotypic genus and includes a single species, ''Pelagomonas calceolata'' which is a unicellular flagellate organism, an ubiquitous constituent of marine picoplankton. It is an ultra-plankto ...
'') belong to
picoplankton
Picoplankton is the fraction of plankton composed by cells between 0.2 and 2 μm that can be either prokaryotic and eukaryotic phototrophs and heterotrophs:
* photosynthetic
* heterotrophic
They are prevalent amongst microbial plankton communit ...
, and some other ('' Sarcinochrysis'') are macroscopic attached organisms.
The subclass contains 13 genera, 3 families and 2 orders (2017):
* Order Pelagomonadales Andersen & Saunders 1993
** Family Pelagomonadaceae Andersen & Saunders 1993
*** genus '' Ankylochrysis'' Billard 1995
*** genus ''
Aureococcus
''Aureococcus anophagefferens'' is a species of heterokont alga. Its cells have a single chloroplast, nucleus, and mitochondrion and an unusual exocellular polysaccharide-like layer. It causes harmful algal bloom
An algal bloom or algae bloo ...
'' Hargraves & Sieburth 1988
*** genus '' Chrysophaeum'' Lewis & Bryan 1941 non Taylor 1951
*** genus '' Pelagococcus'' Norris 1977
*** genus ''
Pelagomonas
''Pelagomonas'' is a genus of heterokont algae. It is a monotypic genus and includes a single species, ''Pelagomonas calceolata'' which is a unicellular flagellate organism, an ubiquitous constituent of marine picoplankton. It is an ultra-plankto ...
'' Andersen & Saunders 1993
* Order Sarcinochrysidales Gayral & Billard 1977
** Family Chrysocystaceae Melkonian, Yoon & Andersen 2018
*** genus '' Chrysocystis'' Lobban, Honda & Chihara 1995
*** genus '' Chrysoreinhardia'' Billard 2000
*** genus '' Sungminbooa'' Yoon & Andersen 2018
** Family Sarcinochrysidaceae Gayral & Billard 1977
*** genus '' Andersenia'' Wetherbee & Waller 2015
*** genus '' Arachnochrysis'' Andersen & Han 2018
*** genus '' Aureoscheda'' Wynne & Andersen 2014
*** genus '' Aureoumbra'' Stockwell et al. 1997
*** genus '' Chrysonephos'' Taylor 1952
*** genus '' Nematochrysopsis'' Billard 2000
*** genus '' Pelagospilus'' Andersen & Graf 2018
*** genus '' Sarcinochrysis'' Geitler 1930
*** genus '' Sargassococcus'' Andersen & Han 2018
It is expected that molecular studies will add more species to this list.