Crepidoodinium cyprinodontum

Super Group: 
Lom and Lawler 1973


Diagnosis_Genus: Crepidoodinium Lom & Lawler 1981. Ectocommensal on gills of estuarine and marine fishes. Trophont is attached by its basal end flattened into a broad holdfast bearing projections ("rhizoids") with finger-like tips which closely adhere to the host cell membrane without penetrating inside the host cell. No stomopode. Well developped chloroplasts. Theca without plates. An extremely spongy cytoplasm with a system of interlinked lacunae and vacuoles with starch grains, subthecally located mucocysts and acontobolocysts. No digestive vacuoles. Nucleus without interphasic condensed chromosomes.  Dinospore without stigma.
Diagnosis_Species: Crepidoodinium cyprinodontum Lawler 1967. Trophont (35 - 673 µm long, 11-152 µm wide is elongated, somewhat flattened, green-pigmented. Attached to the gill filament by 2-10 major holdfasts (or rhizoids), that run along its surface. Additional minor holdfast penetrates inside the gill tissue. Mature trophont retracts its holdfasts and encyst (cysts 44-61 µm X 301-363 µm). First division is longitudinal and equal, following by divisions equal and repeated, with the restauration of the resting cell stage between divisions. Up to 11 divisions in minimum time of 22 hours, forming 512 to 2048 dinospores. Dinospores 5-9 µm long by 2-5 µm wide.

This parasite does not directly destroy host cells. It should be considered as an ectocommensal rather than a true ectoparasite.

Body_trophont_length: 35 - 673 µm
Body_trophont_wide: 11-152 µm
Body_spore_length: 5-9 µm
Body_spore_wide: 2-5 µm
Progeny: 512-2048 spores


cyprinodontum: parasites infesting fishes of the family Cyprinodontidae.

Type species

This is the type species of the genus.

Type illustration / Type locality / Type specimen

Type host: Fundulus majalis.
Type locality: York River, Gloucester Point, Gloucester country, Virginia, US.
Type specimen: Holotype (USNM Protozoan coll. No. 23856) and paratype (USNM Protozoan coll. Nos. 23857 and 23880), deposited at the US National Museum.


Substrate: epizoic
Sociability_trophont: gregarious
Salinity: marine
Salinity: variable

Life cycle

Generation: <1 month
Reproduction_mode: asexual
Symbiont: horizontal

Feeding behaviour


Mode of locomotion


Observation site(s)


Displaying 1 - 8 of 8
Association with... Region origin Name of site In reference...
Cyprinodon variegatus Virginia York river Gloucester point
Cyprinodon variegatus Mississippi Sound
Fundulus heteroclitus Virginia York river Gloucester point
Fundulus luciae Virginia Tributary creek
Fundulus majalis Virginia York river Gloucester point
Fundulus similis Mississippi Sound
Adinia xenica Mississippi Sound
Lucania parva Virginia York river Gloucester point