Dinokaryota is a main grouping of dinoflagellates. They include all species where the

nucleus Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to: *Atomic nucleus, the very dense central region of an atom * Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucl ...

remains a

dinokaryon A dinokaryon is a eukaryotic nucleus present in dinoflagellates in which the chromosomes are fibrillar in appearance (i.e. with unmasked DNA fibrils) and are more or less continuously condensed. The nuclear envelope does not break down during mi ...

throughout the entire

cell cycle The cell cycle, or cell-division cycle, is the series of events that take place in a cell that cause it to divide into two daughter cells. These events include the duplication of its DNA (DNA replication) and some of its organelles, and sub ...

, which is typically dominated by the haploid stage. All the "typical" dinoflagellates, such as '' Peridinium'' and ''

Gymnodinium ''Gymnodinium'' is a genus of dinoflagellates, a type of marine and freshwater plankton. It is one of the few naked dinoflagellates, or species lacking armor known as cellulosic plates. Since 2000, the species which had been considered to be par ...

'', belong here. Others are more unusual, including some that are colonial,

amoeboid An amoeba (; less commonly spelled ameba or amœba; plural ''am(o)ebas'' or ''am(o)ebae'' ), often called an amoeboid, is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and retracting pseudopo ...

, or

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

. ''

Symbiodinium : ''This is about the genus sometimes called Zoox. For the company, see Zoox (company)'' ''Symbiodinium'' is a genus of dinoflagellates that encompasses the largest and most prevalent group of endosymbiotic dinoflagellates known. These unicell ...

'' contains the symbiotic zooxanthellae. The non-photosynthetic members are believed to derive from photosynthetic ancestors.

Classification

Dinoflagellates are classified by

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines * Morphology (archaeology), study of the shapes or forms of artifacts * Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...

With a theca

Species with a theca are divided into four orders, based on the arrangement of the armor plates: *

Dinophysiales Dinophyceae is a class of dinoflagellates. Taxonomy * Class Dinophyceae Pascher 1914 eridinea Ehrenberg 1830 stat. nov. Wettstein; Blastodiniphyceae Fensome et al. 1993 orthog. emend.** Order Haplozoonales aplozooidea Poche 1913*** Family H ...

- e.g. ''

Dinophysis ''Dinophysis'' is a genus of dinoflagellatesAlgaeBase''Dinophysis'' Ehrenberg, 1839/ref> common in tropical, temperate, coastal and oceanic waters.Hallegraeff, G.M., Lucas, I.A.N. 1988: The marine dinoflagellate genus Dinophysis (Dinophyceae): ph ...

'' * Gonyaulacales - e.g. ''

Ceratium The genus ''Ceratium'' is restricted to a small number (about 7) of freshwater dinoflagellate species. Previously the genus contained also a large number of marine dinoflagellate species. However, these marine species have now been assigned to ...

'', '' Gonyaulax'' *

Peridiniales Peridiniales is an order of dinoflagellates. Below is a uncritical list of the families in Peridinales, but molecular phylogenetics circumscribe the group in a stricter sense.Žerdoner Čalasan A, J Kretschmann & M Gottschling (2019): ''They are ...

- e.g. '' Peridinium'' *

Prorocentrales The 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 ...

- e.g. ''

Prorocentrum The 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 a ...

'' The Peridiniales are probably paraphyletic to the others, and on

rRNA Ribosomal ribonucleic acid (rRNA) is a type of non-coding RNA which is the primary component of ribosomes, essential to all cells. rRNA is a ribozyme which carries out protein synthesis in ribosomes. Ribosomal RNA is transcribed from ribosoma ...

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.

Without theca

The groups of dinoflagellates without theca are understood to be artificial, and are mostly

polyphyletic A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ...

. Many of the genera, such as ''

'' and ''

Amphidinium ''Amphidinium'' is a genus of dinoflagellates. The type for the genus is '' Amphidinium operculatum'' Claparède & Lachmann. The genus includes the species '' Amphidinium carterae'' which is used as a model organism. As dinoflagellates, ''Amphi ...

'', are also polyphyletic. However some may approximate monophyletic groups, such as the

Suessiales Suessiales is an order of dinoflagellates. It includes '' Borghiella'', '' Glenodinium'', ''Polarella'' and ''Symbiodinium : ''This is about the genus sometimes called Zoox. For the company, see Zoox (company)'' ''Symbiodinium'' is a genus ...

, and some have not been studied phylogenetically. * Gymnodiniales - e.g. ''

'', ''

'' * Ptychodiscales *

- e.g. ''

'' * Desmocapsales * Phytodiniales (includes Dinococcales, Dinotrichales) - e.g. '' Dinamoeba'', ''

Pfiesteria ''Pfiesteria'' is a genus of heterotrophic dinoflagellates that has been associated with harmful algal blooms and fish kills. ''Pfiesteria'' complex organisms (PCOs) were claimed to be responsible for large fish kills in the 1980s and 1990s on th ...

'' * Thoracosphaerales

Blastodiniales

There is also a group of parasitic dinoflagellates, the Blastodiniales, that do not have dinokarya during their trophic stage. Because of this, they have been treated as a separate class Blastodiniphyceae, but some or all may actually have developed within the Dinophyceae.

References

{{Taxonbar, from=Q5278590 Dinoflagellate taxonomy Superclasses (biology) Taxa described in 1993