(Krasske) Lange-Bert. in Krammer and Lange-Bert. 2004
Credit: Marina Potapova
Valves elliptic
Axial area on raphe valve narrow
Raphe valve with transversely elliptic or rectangular central area
Rapheless valve with wide lanceolate axial area
Both valves with stria density 15-18 in 10 µm
Valves are elliptic. The raphe valve has a narrow axial area and a transversely elliptic or rectangular central area. The rapheless valve has a wide lanceolate axial area and lacks a distinct central area.