Cyphoderia spec.

Diagnosis: shell pyriform, strongly curved, resembling a croissant, banana or boomerang, colorless (new shells) or yellowish to brownish (older shells), composed of numerous more or less small circular scales; scales not overlapping; shell in cross-section circular or faintly compressed; aperture circular or broad-elliptical; curved neck; fundus hemispherical or  tapering to a more or less sharply-rounded apex; plasma with many dark granules; nucleus large, granular; fine straight filopodia.

Dimensions: 93-100 µm long

Ecology: Sediment of a small river in the Netherlands, some deep Swiss lakes.

Remarks: I have found this species in November 2011 in a sample from the river Neerbeek in Neer, Netherlands. October 2012, I found similar specimens in the river Weser near Bodenwerder, Germany.

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