Dinophyceae
Encyclopedia
Dinokaryota is the main class of dinoflagellate
s. They include all species where the nucleus
remains a dinokaryon throughout the entire cell cycle, which is typically dominated by the haploid stage. All the "typical" dinoflagellates, such as Peridinium
and Gymnodinium
, belong here. Others are more unusual, including some that are colonial, amoeboid, or parasitic. Symbiodinium contains the symbiotic zooxanthellae.
The non-photosynthetic members are believed to derive from photosynthetic ancestors.
The Peridiniales are probably paraphyletic
to the others, and on rRNA trees they are mixed with the species that lack thecae. The other three orders are probably monophyletic
, with the Dinophysiales and Prorocentrales as close relatives, united by the presence of a sagittal suture dividing the theca in two.
However, on rRNA trees the Prorocentrales are split up.
and Amphidinium
, are also polyphyletic. However some may approximate monophyletic groups, such as the Suessiales
, and some have not been studied phylogenetically.
Dinoflagellate
The dinoflagellates are a large group of flagellate protists. Most are marine plankton, but they are common in fresh water habitats as well. Their populations are distributed depending on temperature, salinity, or depth...
s. They include all species where the nucleus
Cell nucleus
In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...
remains a dinokaryon throughout the entire cell cycle, which is typically dominated by the haploid stage. All the "typical" dinoflagellates, such as Peridinium
Peridinium
Peridinium is a genus of motile, marine and freshwater dinoflagellates. Their morphology is considered typical of the armoured dinoflagellates, and their form is commonly used in diagrams of a dinoflagellate's structure. Peridinium can range from 30-70 μm in diamter, and has very thick thecal...
and Gymnodinium
Gymnodinium
Gymnodinium is a genus of dinoflagellates. It is one of the few naked dinoflagellates, or species lacking armor . Since 2000, the species which had been considered to be part of Gymnodinium have been divided into several genera, based on the nature of the apical groove and the biochemistry...
, belong here. Others are more unusual, including some that are colonial, amoeboid, or parasitic. Symbiodinium contains the symbiotic zooxanthellae.
The non-photosynthetic members are believed to derive from photosynthetic ancestors.
With a theca
Species with a theca are divided into four orders, based on the arrangement of the armor plates:- PeridinialesPeridinialesPeridiniales is an order of Dinoflagellates. Below is the list of the families in Peridinales.*Amphilothaceae,*Archaeosphaerodiniopsidaceae,*Blastodiniaceae,*Calciodinellaceae,*Ceratiaceae,*Cladopyxidaceae,*Coccidinaceae,*Crypthecodiniaceae,...
- e.g. PeridiniumPeridiniumPeridinium is a genus of motile, marine and freshwater dinoflagellates. Their morphology is considered typical of the armoured dinoflagellates, and their form is commonly used in diagrams of a dinoflagellate's structure. Peridinium can range from 30-70 μm in diamter, and has very thick thecal... - Gonyaulacales - e.g. CeratiumCeratiumCeratium is a genus of dinoflagellate....
, GonyaulaxGonyaulaxGonyaulax is a genus of Alveolata. They undergo rapid multiplication and they make the sea appear red. They produce a potent toxin known as Saxitoxin which affects nerve impulses and can lead to paralysis of muscles and may eventually end in asphyxiation.Members are covered by closely fitting... - Dinophysiales - e.g. DinophysisDinophysisDinophysis is a dinoflagellate genus with more than 200 recognised species found in coastal and oceanic waters throughout the World . Cell densities are usually neglestible, but favourable conditions can result in massive blooms also known as red tides...
- ProrocentralesProrocentralesThe Prorocentrales are a small order of dinoflagellates. They are distinguished by having their two flagella inserted apically, rather than ventrally as in other groups. One flagellum extends forward and the other circles its base, and there are no flagellar grooves. This arrangement is called...
- e.g. Prorocentrum
The Peridiniales are probably paraphyletic
Paraphyly
A group of taxa is said to be paraphyletic if the group consists of all the descendants of a hypothetical closest common ancestor minus one or more monophyletic groups of descendants...
to the others, and on rRNA trees they are mixed with the species that lack thecae. The other three orders are probably monophyletic
Monophyly
In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group. The term is synonymous with the uncommon term holophyly...
, with the Dinophysiales and Prorocentrales as close relatives, united by the presence of a sagittal suture dividing the theca in two.
However, on rRNA trees the Prorocentrales are split up.
Without theca
The groups of dinoflagellates without theca are understood to be artificial, and are mostly polyphyletic. Many of the genera, such as GymnodiniumGymnodinium
Gymnodinium is a genus of dinoflagellates. It is one of the few naked dinoflagellates, or species lacking armor . Since 2000, the species which had been considered to be part of Gymnodinium have been divided into several genera, based on the nature of the apical groove and the biochemistry...
and Amphidinium
Amphidinium
Amphidinium is a genus of dinoflagellate.It includes the species Amphidinium carterae....
, are also polyphyletic. However some may approximate monophyletic groups, such as the Suessiales
Suessiales
Suessiales is a group of dinoflagellates.It includes Polarella and Symbiodinium....
, and some have not been studied phylogenetically.
- Gymnodiniales - e.g. GymnodiniumGymnodiniumGymnodinium is a genus of dinoflagellates. It is one of the few naked dinoflagellates, or species lacking armor . Since 2000, the species which had been considered to be part of Gymnodinium have been divided into several genera, based on the nature of the apical groove and the biochemistry...
, AmphidiniumAmphidiniumAmphidinium is a genus of dinoflagellate.It includes the species Amphidinium carterae.... - Ptychodiscales
- SuessialesSuessialesSuessiales is a group of dinoflagellates.It includes Polarella and Symbiodinium....
- e.g. Symbiodinium - Desmocapsales
- Phytodiniales (includes Dinococcales, Dinotrichales) - e.g. Dinamoeba, PfiesteriaPfiesteriaPfiesteria is a genus of heterotrophic dinoflagellates that has been associated with harmful algal blooms and fish kills. Pfiesteria complex organisms were claimed to be responsible for large fish kills in the 1980s and 1990s on the coast of North Carolina and in tributaries of the Chesapeake Bay...
- Thoracosphaerales