Rhynchopus (rink-owe-puss) is one of a small number of genera that make up the diplonemids, a subset of euglenozoa. Although not widely reported, they are often encountered in especially marine habitats where they consume detritus, algae, and other moderately sized particles. They have two flagella which insert into a shallow subapical pocket. There are three genera which look similar: Rhynchopus with a papillum and relatively deep flagellar pocket, Diplonema with two short flagella, and Hemistasia with long flagella. The species are polymorphic, making species and generic boundaries very hard to establish. We assign this organism to Rhynchopus because of the papillum. Differential interference contrast. This picture was taken by David Patterson, Linda Amaral Zettler, Mike Peglar and Tom Nerad from cultures and other materials maintained at the American Type Culture Collection during 2001. Image copyright: D. J. Patterson, L Amaral-Zettler, M. Peglar and T. Nerad, image used under license to MBL (micro*scope).
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American Type Culture Collection
|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. |