Apodinium mycetoides

Super Group: 
Alveolata
Phylum: 
Dinophyta
Class: 
Dinophyceae
Family: 
Apodinidae
Genus: 
Apodinium
Species: 
mycetoides
Authority: 
Chatton 1907

Diagnosis

Diagnosis_Genus: Apodinium Chatton 1907. Ectoparasite of appendicularians, attached by a peduncle. Sporogenesis occurs during the trophont stage by palisporogenesis.
Diagnosis_Species: Apodinium mycetoides Chatton 1907. This species is specifically fixed between the two gill slits (the spiracles) of its host. Encysted young individuals (diameter: 10 µm) are attached by a long peduncle (about 60-200 µm long, 2-6 µm large), protected by a sheath. The trophont has a bi-energid nucleus, located close to the peduncle, and contains aqueus lacunal material at the opposite side (apex of the cell). The peduncle ends by rhizoids (devoid of sheath), that penetrate inside the host tegument and seperate into two major branches. The parasite becomes pyriform during its grow. Palisporogenesis starts when the trophont has 50-60 µm long x 40-60 µm wide. One daughter cell (the gonocyte), located at the apex, will actively divided producing sporocytes, whilst the other encysts and continues to grow (trophocyte). A new envelope is produced for each daughter cell and the surrounding mother cuticule remains intact for a while; up to 4 sporocyte generations can be observed within the same mother cuticule. The rupture of the mother cuticule releases the dinospores. What remains from this cuticule is still visible on the peduncule as a collar-shape membrane (up to 5 have been observed).
Body_spores: <10µm
Body_trophont_lenght: 50-60 µm
Body_trophont_wide: 40-60 µm

Etymology

mycetoides: young trophont resembles to germinating fungi.

Type species

This is the type species of the genus.

Type illustration / Type locality / Type specimen

Type host: Fritillaria pellucida
Type locality: Banyuls-sur-mer (France)

Ecology

Substrate: epizoic
Salinity: marine

Life cycle

Generation: <1 month
Reproduction_mode: asexual
Symbiont: horizontal

Feeding behaviour

Parasitism
Osmotrophy

Mode of locomotion

Flagellum_spore:2

Observation site(s)

HOSTS

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Association with... Region origin Name of site In reference...
Fritillaria pellucida Banyuls-sur-mer