No picture so far.
Cells have many small chloroplasts and setae without chloroplasts. Chains are often long and more or less twisted around the chain axis. The inner setae have basal part well inside valve margin and point of crossing is near the chain edge. There are two types of inner setae, most of them are thin, but some are thicker with spines and directed towards the end of the chain. The valves of the resting spore are differently curved.
Apical axis measures 7-40 um.
Throndsen, J., Hasle, G.R. and Tangen, K., 2007. Phytoplankton of Norwegian coastal waters. Almater Forlag AS. 341 pp.