Eunotia diodon has broader valves and a lower stria density at the valve center. Eunotia bidentuloides has smaller valves, a higher stria density, and more acute dorsal undulations. Eunotia islandica has a more curved ventral margin, broader valves, and more pointed dorsal undulations. Eunotia montuosa has broader valves, lower stria density, and less rounded dorsal undulations. Eunotia subherkiniensis has a lower stria density and capitate apices.

LM scalebar = 10 µm
Eunotia bidentula LM1 Eunotia bidentula LM2 Eunotia bidentula LM3 Eunotia bidentula LM4 Eunotia bidentula LM5 Eunotia bidentula LM6
Length Range
22-34 µm
Width Range
4.0-8.2 µm
Striae in 10 µm
14-17 at mid-valve; up to 20 at the ends

Eunotia montuosa

Furey, Lowe and Johansen 2011

Eunotia montuosa LM2 Eunotia montuosa LM3 Eunotia montuosa LM4 Eunotia montuosa LM1 Eunotia montuosa LM5 Eunotia montuosa LM6 Eunotia montuosa LM7
Length Range
31-59 µm
Width Range
7-13 µm
Striae in 10 µm
7-9 in the center valve, 10-14 at the ends

Eunotia subherkiniensis

Lange-Bert. 2011

Eunotia subherkiniensis LM1 Eunotia subherkiniensis LM2 Eunotia subherkiniensis LM3 Eunotia subherkiniensis LM6 Eunotia subherkiniensis LM4 Eunotia subherkiniensis LM7 Eunotia subherkiniensis LM8
Length Range
15-33 µm
Width Range
4.5-8.5 µm
Striae in 10 µm
11-14 in the center valve

Also compare to

Eunotia islandica

Østrup 1918

Eunotia bidentuloides

Foged 1977