Linear with almost circular ends. Triundulate, ends without shoulders, capitate. Pole broad or slightly smaller then valve middle. Raphe is weakly lateral, not bent in middle. Centeral nodule round and relatively large. Central area rhomboid, widening to broad frascia. (Krammer 1992a).
This taxon is found in oligotrophic waters. Found in the sediment level of water bodies, rarely in water with higher electrolyte content(Krammer 1992a; Beaver 1981).