Compare

The striae of Diploneis bombus and D. crabro are crossed by several longitudinal ribs. 

Diploneis stroemii is distinguished by parallel, uninterrupted stria in the middle of the valve. 

Diploneis incurvata has smaller valves, higher stria density, and axial area that narrows significantly near the central area

LM scalebar = 10 µm
Diploneis interrupta LM7 Diploneis interrupta LM6 Diploneis interrupta LM5 Diploneis interrupta LM4 Diploneis interrupta LM3 Diploneis interrupta LM1 Diploneis interrupta LM2
Length Range
35-82 µm
Width Range
13-28 µm
Striae in 10 µm
12-15

Diploneis bombus

(Ehrenb.) Ehrenb. 1853

Diploneis bombus LM2 Diploneis bombus LM3 Diploneis bombus LM7 Diploneis bombus LM5 Diploneis bombus LM1 Diploneis bombus LM4 Diploneis bombus LM6
Length Range
42-50 µm
Width Range
19-25 µm
Striae in 10 µm
6-8

Also compare to

Diploneis stroemii

Hust.

Diploneis incurvata

(Gregory) Cleve

Diploneis crabro

Ehrenb.