Syndinium turbo

Super Group: 
Chatton 1910
Syndinium minutum
Synhemidinium rostratum
Syndinium rostratum
Cochlosyndinium corycaei
Atelodinium microsporum Chatton 1920
Atelodinium parasicum Chatton 1920


Trophont maturation: First stage are enclosed inside a capsule localised close to the intestinal tube of the host. Such young Syndinium occur in the various copepodite stages of their hosts, and when a gonad is present it is always already more or less degenerate. Mature capsules (dim. 30-50 µm) are ellipsoidal. Nuclear division parallels the growth of the parasite  without their separation of individual cells. The capsule disappears, as the plasmodium grows into a large lobed mass which gradually spreads through all the body-cavity, sending its varicose extensions along the interstices between the muscles and into the appendages and abdomen. Ultimately all available spaces are filled with the plasmodium, which presses on the wall of the gut: the gonad is completely destroyed; only the heart and circulatory channels remain quite clear to the end. Infested copepod are opaque, with slow motion. At maturity the host is killed.
The mitotic divisions of the nuclei have been well observed by Chatton 1910, 1952, and described as the syndinid mitosis. The V-shaped chromosomes (5 in total) are always condensed and permanently attached at their apexes to a specific area of the nuclear membrane. Trichocysts present in the cytoplasm (Soyer 1974).
Sporogenesis: The sporogenesis occurs inside the host by the fragmentation of the plasmodium. Each nuclei is allocated to a future spore, together with a small amount of cytoplasm. Only remains the cuticule from the copepod. the sporogenesis takes 2 hours, and was preferentially observed at the end of the day (3-7 pm).
Spores: Spores formed inside the host start to swimm actively to be released outside the host. No cyst detected. Three type of spores: macrospores (15 µm) and microspores (8 x 5 µm), and ovoid, with a rostre (15 µm) (the Oxyrrhis-like cell). Based on the polymorphism of Syndinium spores, Chatton (1922) later concluded that the three different spore types were three separate species, and named the macrospores, microspores and rostrate spores, S. turbo, S. minutum, and S. rostratum respectively. However, SSU and ITS1-ITS2 were identical, leading to the conclusion that all spore morphotypes belong to the same species (Skovgaard et al. 2005).
After the discovery that another Syndinium species occurs in Corycaeus sp. based upon divergence in the SSU and ITS sequences (Skovgaard et al. 2005), S. turbo is suspected to be restricted to a narrow host spectrum.
Body_macrospores_length: 15 µm
Body_microspores_length: 8 µm
Body_microspores_wide: 5 µm
Body_rostrated_spores_length: 15 µm
Body_capsules: 30-50 µm

Type species

This is the type species of the genus.

Type illustration / Type locality / Type specimen

Type locality: Banyuls-sur-Mer (France).
Type specimen: P654 Chatton 1910.
Type host: Paracalanus parvus.


Substrate_trophont: endozoic
Substrate_trophont: extracellular
Substrate_spores: planktonic
Sociability_trophont: solitary
Sociability_trophont: sometime gregarious (Jepps 1937)
Salinity: marine
pH: neutral

Life cycle

Infection potentially starts by the ingestion of the spore, due to proximity of young capsules with the intestinal tube.
Three types of spores are produced, but each infected copepod always released only one type of Syndinium zoospore.

Phases_alternance: haplontic
Generation: <1 month
Reproduction_mode: asexual
Symbiont: horizontal
Symbiont: horizontal_ingestion

Feeding behaviour


Mode of locomotion


Observation site(s)


Displaying 1 - 14 of 14
Association with... Region origin Name of site In reference...
Calanus finmarchicus Glasgow
Clausocalanus arcuicornis Banyuls-sur-mer
Chatton E (1920) Les péridiniens parasites. Morphologie, Reproduction, Ethologie. . Archives de Zoologie Expérimentale et Générale 59:1-475.
Clausocalanus arcuicornis Catalunya off port Olympic
Clausocalanus arcuicornis Banyuls-sur-mer
Corycaeus crassiusculus Banyuls-sur-mer
Chatton E (1920) Les péridiniens parasites. Morphologie, Reproduction, Ethologie. . Archives de Zoologie Expérimentale et Générale 59:1-475.
Euterpina acutifrons Catalunya off port Olympic
Oithona similis Catalunya off port Olympic
Paracalanus indicus Melbourne Port Phillip Bay
Paracalanus parvus Catalunya off port Olympic
Paracalanus parvus south- easternTyrrhenianSe Gulf of Naples
Paracalanus parvus Tyrrhenian Sea Gulf of Naples
Paracalanus parvus Saronic Gulf
Paracalanus parvus Banyuls-sur-mer
Chatton E (1920) Les péridiniens parasites. Morphologie, Reproduction, Ethologie. . Archives de Zoologie Expérimentale et Générale 59:1-475.
Onchocorycaeus giesbrechti Catalunya off port Olympic

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