Diploneis marginestriata is very similar but it has larger valves and a lower stria density (17-18 in 10 μm). Diploneis modica is smaller and has and considerably narrower internal canals. Diploneis oculata is distinguished by a constantly higher stria density (~22 in 10 μm) and narrower valves. Diploneis galloprovincialis has broader valves.
BioData Reference
Krammer and Lange-Bertalot 2/1 Pl 110 Fig 13-15
BioData Reference
Krammer and Lange-Bertalot 2/1 Pl 110 Fig 9-12