Diploneis pseudovalis is very similar, and overlaps in size range. While D. pseudovalis somewhat more oblong shape, these taxa may be easily confused and D. pseudovalis was commonly reported in Montana (L.L. Bahls, personal communication). Diploneis puella is smaller in size and has a narrow axial area, small central area, and higher stria density. Diploneis heteromorphiforma has uniseriate striae, becoming biseriate toward the valve margin. Diploneis iovanovskae much more narrowly spaced areolae, 35–40 in 10 μm.

Note that the differences between D. pseudovalis, D. iovanovskae, and D. texana are mainly in the number of areolae that make up the striae, a feature that requires optimal illumination and a critical eye. The striae are biseriate in D. pseudovalis, triseriate and very fine in D. iovanovskae, and triseriate becoming multiseriate in D. texana. Other features either overlap, or are of questionable value, considering possible environmental influences on morphology.

LM scalebar = 10 µm
Diploneis texana LM7 Diploneis texana LM8 Diploneis texana LM9 Diploneis texana LM11 Diploneis texana LM12 Diploneis texana LM10
Length Range
20-29 µm
Width Range
11-13 µm
Striae in 10 µm

Diploneis puella

(Schumann) Cleve 1894

Diploneis puella LM4 Diploneis puella LM5 Diploneis puella LM3 Diploneis puella LM2 Diploneis puella LM6 Diploneis puella LM1
Length Range
10-12 µm
Width Range
6-7 µm
Striae in 10 µm

Also compare to

Diploneis pseudovalis

BioData Reference
Krammer and Lange-Bertalot 2/1 Pl 108 Fig 11-13

Diploneis iovanovskae

Lange-Bert. and Fuhrmann

Diploneis heteromorphiforma

Metzeltin, Lange-Bert. and Soninkhishig