Amoebophrya sticholonchae

Super Group: 
Alveolata
Phylum: 
Dinophyta
Class: 
Syndinea
Order: 
Syndiniales
Family: 
Amoebophyidae
Genus: 
Amoebophrya
Species: 
sticholonchae
Cluster: 
MALV II
Authority: 
Koeppen 1894

Diagnosis

Diagnosis_Genus: Amoebophrya Koeppen 1984. Intracellular parasites. Smallest trophonts observed have 3 µm long, a gymnodiniales form, with a large hypocone and a small rudimentary epicone. The hypocone broadens at its base and forms a cup-shaped circumvallation, turning in spiral. The hypocone starts to cover the epicone (in other word, the epicone becomes progressively invaginated into the hypocone, forming a cavity, the mastigocoel, which is a characteristic of the genus Amoebophrya. This mastigocoel remains open by a small aperture at the apex of the trophont. Sporogenesis starts rapidly during this transformation. The inner surface of the mastigocoel is furnished with helically coiled ridges as a result of a continuous lengthening of the previous dinospore girdle during the trophic growth. Along these ridges countless flagella are inserted. Flagella of  future dinospores (the free-living stage of the parasite) are produced inside the mastigocoel. At the end of the intracellular maturation, flagella started to beat, and what was the epicone at the origin, directed through the aperture of the mastigocoel, moved forward. This evagination make the flagella outside the structure, which is now called the vermiform. This action breacks out the host membrane, releasing the vermiform outside. This vermiform is closed forward (at the epicone side), but open in the back. When release, this part forms a large digestive vacuole that contains what remains from the host. This vermiform considerably strechs out with time. The spore chain forming the vermiform rapidly separates to produce spores (gymnodinial shape), generally of two different sizes (macrospores and microspores). These spores have a large epicone and a reduced hypocone (the reverse of what is observed during the first stage of the trophont).

Diagnosis_species: Amoebophrya sticholonchae Koeppen 1894. The trophont develops outside of the central capsule of its host (Sticholonche), and could be considered as an ectoparasite. The trophont develops similarly to A. grassei, but could be either plurinucleate or having  a single voluminous nucleus. A cytopharynx (see the description of Amoebophrya ceratii) is observed, but not well developped. The digestive vacuole of the vermiform includes the central capsule of its host, which persits for a long time before to be totally digested. Two type of spores (macro 7-8 µm long and microspores 2 µm long) are produced. 

Body_spores_length: 7-8 µm (macrospores)
Body_spores_length: 2 µm (microspores)

Etymology

Amoebophrya: looks like to an amibe (Koeppen 1894).
sticholonchae: infects Sticholonche (zanclea), Koeppen 1894.

Type species

This is the type species of the genus.

Ecology

Substrate_spores: planktonic
Substrate_trophont: endozoic
Salinity: marine
pH: neutral

Feeding: parasitism (by phagotrophy)

Life cycle

Phases_alternance: haplontic
Generation: <1 month

Reproduction_mode: asexual

Symbiont: horizontal_active-penetration

Feeding behaviour

Parasitism
Phagotrophy

Mode of locomotion

Motility_spore:motile_swimming
Flagellum_spore:2

Observation site(s)

HOSTS

Displaying 1 - 2 of 2
Association with... Region origin Name of site In reference...
Sticholonche zanclea
Sticholonche zanclea Villefranche-sur-mer