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P. rhumbleri, right: 126 µm

Pontigulasia rhumbleri Hopkinson 1919

Diagnosis: test pyriform, compressed; composed of diatom-frustules and mineral grains, bound together by an organic cement. Aperture elliptical or sub-circular without any definite neck or constriction of the test. Internal bridge ribbon-shaped, widening towards the ends, placed centrally a short distance within the aperture and attached to the broader sides of the test.

Dimensions: Hopkinson 130-140 µm; my measurements: 112-168 µm

Ecology: in Sphagnum and aquatic vegetation in shallow water.

Pontigulasia rhumbleri Hopkinson 1919
Pontigulasia rhumbleri, with aperture and bridge, shell 112 µm -Tirol, Austria
Pontigulasia rhumbleri
Pontigulasia rhumbleri, with bridge (right), shell 120 µm -Tirol, Austria
Pontigulasia rhumbleri
Both arrows indicate the network structure of the organic cement
Pontigulasia rhumbleri
Bridge inside the test, as seen through the aperture
Pontigulasia rhumbleri
Pontigulasia rhumbleri
Pontigulasia rhumbleri, bridge
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