The ochrophytes, subphylum Ochrophytina, is a group of mostly

photosynthetic Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in ...

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. Their

plastid The plastid (Greek: πλαστός; plastós: formed, molded – plural plastids) is a membrane-bound organelle found in the cells of plants, algae, and some other eukaryotic organisms. They are considered to be intracellular endosymbiotic cyanobac ...

is of

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 ...

origin. The classification of the group is still being worked out. Originally, the ochrophytes were regarded as a phylum denominated Ochrophyta. Some authors (e.g.,

Cavalier-Smith Thomas (Tom) Cavalier-Smith, FRS, FRSC, NERC Professorial Fellow (21 October 1942 – 19 March 2021), was a professor of evolutionary biology in the Department of Zoology, at the University of Oxford. His research has led to discov ...

) divided it into two subphyla, Phaeista Cavalier-Smith 1995 (comprising Hypogyristea and Chrysista in some classifications, or Limnista and Marista in others) and

Khakista The ochrophytes, subphylum Ochrophytina, is a group of mostly photosynthetic heterokonts. Their plastid is of red algal origin. The classification of the group is still being worked out. Originally, the ochrophytes were regarded as a phylum den ...

Cavalier-Smith, 2000 (comprising '' Bolidomonas'' and diatoms). Others prefer not to use the subphyla, listing only lower taxa (e.g., Reviers, 2002, Guiry & Guiry, 2014). However, it is currently regarded as a subphylum inside of the phylum Gyrista, along with

Pseudofungi Pseudofungi is a grouping of heterokonts, also known as the Heterokontimycotina. It consists of the Oomycota and Hyphochytridiomycetes. Although numerous biochemical, ultrastructural, and genetic traits clearly place them in the heterokonts, th ...

and Bigyromonada. It contains two infraphyla: Diatomista, containing diatoms and related groups, and Chrysista, containing brown and golden algae and related groups.

Phylogeny

The cladogram below shows the evolutionary relationships between all ochrophyte classes. It is based on the latest phylogenetic analyses:

Classification

Below is the present classification of ochrophytes, with the inclusion of three new classes of algae described in 2019, 2020 and 2021. *Infraphylum Chrysista **Superclass Limnistia ***Class

Eustigmatophyceae Eustigmatophytes are a small group (17 genera; ~107 species) of eukaryotic forms of algae that includes marine, freshwater and soil-living species. All eustigmatophytes are unicellular, with coccoid cells and polysaccharide cell walls. Eust ...

***Class Chrysomonadea

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'', which ...

***Class Picophagea Synchromophyceae **Superclass Raphidoistia ***Class Raphidomonadea ****Subclass

Raphidophycidae The raphidophytes, formally known as Raphidomonadea or Raphidophyceae (formerly referred to as Chloromonadophyceae and Chloromonadineae), are a small group of eukaryote, eukaryotic algae that includes both marine (ocean), marine and fresh water, ...

****Subclass Raphopoda **Superclass Fucistia ***Class Aurophyceae ****Subclass Aurearenophycidae ****Subclass

Phaeothamniophycidae Phaeothamniophycidae is a subclass (biology), class of heterokont algae. It contains two orders, Phaeothamniales and Pleurochloridellales, and consists of species separated from Golden algae, Chrysophyceae. Taxonomy * Order Pleurochloridellales ...

***Class Chrysomerophyceae ***Class Chrysoparadoxophyceae ***Class Phaeosacciophyceae ***Class Schizocladiophyceae ***Class

Phaeophyceae Brown algae (singular: alga), comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and ...

Fucophyceae ; Melanophyceae (“brown algae”) ****Subclass Discosporangiophycidae ****Subclass Ishigeophycidae ****Subclass Dictyotophycidae ****Subclass Fucophycidae ***Class

Xanthophyceae Yellow-green algae or the Xanthophyceae (xanthophytes) are an important group of heterokont algae. Most live in fresh water, but some are found in marine and soil habitats. They vary from single-celled flagellates to simple colonial and filamen ...

Heterokontae ">Tribophyceae ; Heterokontae (“yellow-green algae”) *Infraphylum Diatomista **Superclass Hypogyrista ***Class Dictyochophyceae

Dictyochia ; Alophycidae 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 Olisthodisca ...

****Subclass Pedinellia Actinochrysophyceae (“axodines”) ****Subclass

Pelagophycidae Pelagophycidae is a subclass of heterokont algae.It is the sister group of the axodines. Together, they form the class Dictyochophyceae. All known species are marine. They can be single-celled ( coccoid or flagellate), palmelloid or filamentous ...

Pelagophyceae ">Pelagophyceae.html" ;"title="Pelagophyceae">Pelagophyceae ****?Subclass Sulcophycidae ***Class Pinguiophyceae **Superclass

***Class Bolidophyceae ***Class Diatomeae Bacillariae ; Bacillariophyceae ****Subclass Corethrophycidae ****Subclass Rhizosoleniophycidae ****Subclass Eucentricophycidae ****Subclass Bacillariophycidae Pennatia ; =Pennatophycidae*Ochrophytina ''incertae sedis'' **Class Olisthodiscophyceae

Notes

References

SAR supergroup phyla {{heterokont-stub