Difflugia elegans angustata
Difflugia elegans var. angustata, Gaasterland, 2019

Difflugia elegans var. angustata  (Penard, 1890) Deflandre, 1926

Diagnosis: The variety differs from the type by its more slender pace and its smaller size and the commonly curved spine. The width is proportionately smaller, the mouth remaining substantially similar; nucleus with a limited number of nucleoli; nucleoli with small lacunae.

Dimensions: Length 61-96 µm (n=20); nucleus diameter 14.3 µm (n=1).

Remarks: I found this variety together with a population of of the typical D. elegans in Gaasterland, 2019. The distinction between both groups was clear. Maybe this is not a variety but a true species.

Difflugia elegans angustata
Difflugia elegans var. angustata, Gaasterland
Difflugia elegans - Ferry Siemensma
Difflugia elegans, all shells descended from one specimen which multiplied in a moist-chamber-mount, 79-86 µm long – Naardermeer, 2016.
Difflugia elegans - Ferry Siemensma
Difflugia elegans var. angustata, all shells from the same culture as above, 83-96 µm long – Naardermeer, the Netherlands
Difflugia elegans angustata
Difflugia elegans var. angustata, nucleus
Difflugia bicornis
D. elegans var. angustata; plot of a number of measurements of shells from the Gaasterland location, July 2019. It might be possible that D. bicornis falls within the variation of D. elegans, though the latter has smaller tests, but D. angustata seems a distinct species and not just a variety.
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