This taxon has a valve that is linear or linear-lanceolate but not lanceolate as in the nominate variety. The ends are more gradually attenuated and are broader in relation to the vavle width in the center. The striae are more numerous than in spencerii. The striae, the raphe, the axial area, and the nodules are the same as in the nominate variety (Patrick and Reimer 1966).
Synonyms
Pleurosigma spenceriivar. curvula Grun. inCl. & Grun., K. Svenska vet-Akad. Handl., Ny Foljd, 17(2):60. 1880(Patrick and Reimer 1966).
Ecology
This taxon has been reported from brackish water areas and also from fresh water areas (Patrick and Reimer 1966).