Encyonopsis cesatii and E. cesatii var. geitleri have smaller, narrowly lanceolate valves and less strongly radiate striae near the apices. Encyonopsis stafsholtii is smaller and has long attenuated apices and a distinctly notched central area on the ventral side. Encyonopsis treinishii has a central stigma. Encyonopsis cesatiformis has smaller lanceolate valves and less strongly radiate striae near the apices. Cymbopleura lapponica has wider valves, a larger central area, proximal raphe ends that are deflected ventrally and terminal raphe fissures that are curved toward the dorsal margin.