''Coccidinium'' is a genus of parasitic
syndinian
The Syndiniales are an order of early branching dinoflagellates (also known as Marine Alveolates, "MALVs"), found as parasites of crustaceans, fish, algae, cnidarians, and protists (ciliates, radiolarians, other dinoflagellates). The trophic f ...
dinoflagellates that infect 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 ...
and
cytoplasm
In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. ...
of other marine
dinoflagellate
The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are ...
s.
''Coccidinium,'' along with two other dinoflagellate genera, ''
Amoebophyra'' and ''
Duboscquella
''Duboscquella'' is a genus of dinoflagellates.
It was named in reference to Octave Duboscq (1868–1943), who was a French zoologist, mycologist and parasitologist.
The genus was circumscribed
In geometry, the circumscribed circle or c ...
'', contain species that are the primary endoparasites of marine dinoflagellates. While numerous studies have been conducted on the genus ''
Amoebophyra'', specifically ''
Amoebophyra ceratii'', little is known about ''Coccidinium''. These microscopic organisms have gone relatively unstudied after the initial observations of
Édouard Chatton and
Berthe Biecheler in 1934 and 1936.
The first species of ''Coccidinium'' that were described were ''C. legeri'' and ''C. duboscquii'', found in the cytoplasm of dinoflagellates in brackish waters near
Sète
Sète (; oc, Seta, ), also historically spelt ''Cette'' (official until 1928) and ''Sette'', is a commune in the Hérault department, in the region of Occitania, southern France. Its inhabitants are called ''Sétois'' (male) and ''Sétoises ...
, France.
They have been noted as lacking
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 ...
stages in their life cycles, which is to be expected given their parasitic nature.
Sexual reproduction
Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete ( haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote th ...
has been observed “time and again” in ''C. mesnili'' as stated by Chatton and Biecheler.
History of knowledge
First discovered by Édouard Chatton and Berthe Biecheler in 1934, ''Coccidinium'' was initially observed in the cytoplasm of the dinoflagellates ''
Glenodinium sociale'' and ''
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 ra ...
'' sp., both taken from the waters of Sète.
They identified two species of ''Coccidinium'', ''C. legeri'' and ''C. duboscquii''. In 1936, ''C. mesnili'' and ''C. punctatum'' were added to the list of existing ''Coccidinium'' species by Chatton and Biecheler. They were found in the same brackish waters of Sète, but in two other peridinians: ''
Kryptoperidinium foliaceum'' and ''
Coolia monotis'' respectively.
Etymology
Observations of ''Coccidinium'' showed that they were
coccidian-like in their vegetative and replication stages, but their
dinospores, a
biflagellate
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 ...
zoospore
A zoospore is a motile asexual spore that uses a flagellum for locomotion. Also called a swarm spore, these spores are created by some protists, bacteria, and fungi to propagate themselves.
Diversity Flagella types
Zoospores may possess one or m ...
, resembled syndinian dinoflagellates. Chatton and Biecheler therefore gave this new genera of
endoparasitic dinoflagellates the name of ''Coccidinium''.
Morphology
A complete understanding of ''Coccidinium'' morphology is not yet possible due to insufficient research. There are no other studies completed apart from the initial observations conducted by Chatton & Biecheler in 1934 and 1936, therefore the little information known are based on their descriptions.
In ''C. duboscquii'', the
trophozoite, the feeding form of the parasite, is present in two forms that originate from small uninucleate forms found in close contact with the nucleus of the host and that are distinguished by their load in carbohydrate globules. In the first form, heavy, numerous and large starchy matter are present whereas in the second form this is absent or rare. Recent interpretation of those