Encyonopsis stafsholtii is similar in shape to E. montana, but E. montana has proportionately much larger valves (up to 75 µm long) and a lower stria density (19-22 in 10 µm). Large valves of E. neerlandica are also rhombic-lanceolate, but this taxon lacks a central area. Encyonopsis cesatii has strictly lanceolate valves with abruptly protracted apices and a lower stria density (16-22 in 10 µm).