Genus: Rhizosolenia | Diatom

Order: Biddulphiales
Family: Rhizosoleniaceae

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Description: Long, cylindrical, straight or slightly curved cells with a spine-like process on one end. Cells may be solitary or in short chains.  Valves are conical or subconical and usually have otaria and claspers.  Segmented girdle bands are in longitudinal columns roughly parallel to the pervlavar axis. Cells have numerous small chloroplasts.

Cell Size: Diameter = 13-230um among five most common species.

Distribution: Widespread throughout the world’s oceans.

Monterey Bay species:  R. setigera, R. hebatata, R. styliformis, R. robusta.