Description of Rhynchopus

Diplonemids, Rhynchopus amitus, the type species, was described from Baltic plankton with an elongate pear-shaped body, often more concave along one side than the other. An anterior papilla separated the ingestion apparatus from the flagellar pocket, and the two flagella barely emerged from the pocket of the creeping cell; also seen feeding on the cytoplasm of the planktonic diatom Coscinodiscus, the gills of the crab Cancer irroratus and more recently from the blood and gills of the Norway lobster, Nephrops norvegicus. When starved, these isolates readily produce Bodo-like motile flagellates and it is suggested that the presence of a fully flagellated dispersive phase in the life-cycle serves to distinguish Rhynchopus from Diplonema. Encysted stages are also produced.