Chytriodinium parasiticum
Diagnosis
Diagnosis_Genus: Ectoparasite of crustacean eggs.
Diagnosis_Species: C. parasiticum. Unknown host egg (Peneid?), but this has 160 µm in diameter, and is surrounded by a mucilagenous layer (60-80 µm large). The stalk, which is the functional hypocone, penetrates the egg of the host and starts boring a tunnel (7-8 µm of dimater) inside the mucilagenous layer. The hyposome then penetrates also inside this tunnel but external cuticle remains outside the host. The whole parasite takes a vermiform shape, penetrates in totality inside the tunnel and directs through the embryo. It takes about 24 hours to reach the embryo. The host can survive to the infection if it can maturate during this stage. Then, the parasite penetrates inside the cytoplasm of its host, the stalk enlarges at its base and forms an ampulla used both as a fixative and a feeding apparatus. Absorption of nutrients correlates with the enlargement of a vacuole that reject the trophont cytoplasm and its nucleus that returned to the external cuticle outside the host. At this time, the tunnel retracts whilst the trophont (containing the nucleus) remains at the exterior, forming a funnel. The whole embryo is digested, visibly by osmotrophy. The rest of the sporogenesis as in other species of Chytriodinium.
Body_spores_length: 9 µm
Body_spores_wide: 6 µm
Body_trophont: 20 µm
Etymology
Chytriodinium: because this parasite has morphological homologies with Chytridium, phycomycete parasites.
Type species
The type species for the genus Chytriodinium roseum.
Type illustration / Type locality / Type specimen
Type host: curstacean eggs
Ecology
Substrate: epizoic
Salinity: marine
Life cycle
Generation: <1 month
Reproduction_mode: asexual
Symbiont: horizontal
Feeding behaviour
Mode of locomotion
Reference(s)
Observation site(s)
HOSTS
Association with... | Region origin | Name of site | In reference... |
---|---|---|---|
Copepoda | Naples |
Beiträge zur Kenntnis des perininen. Mitt. aus der Zoll. St. zu Neapel XVIII:1-45. (1906) |
|
Meganyctiphanes norvegica | Villefranche-sur-mer |
Cytologie et cycle évolutif des Chytriodinium (Chatton). Protistologia T. IV:249-262. (1968) |