Placocista lens
Placocista lens, in lateral view (left) and frontal view

 

Placocista lens (Penard, 1899)

Diagnosis: shell broad, ovoid, strongly compressed, with acute lateral border; shell edge smooth, without spines; shell composed of many small scales; along the aperture is an area covered with very minute scales; aperture a broad but very flattened slit, biconvex; nucleus spherical, with fragmented nucleolar material; filopodia.

Dimensions: Length 81 µm, L/B = 0.8, scales ca. 12 µm.

Ecology: Rare. I have found one specimen in 1979 in a sample from the Dammerkade, Ankeveen, one in 2011 in a sample from a small river in Neer, Zuid-Limburg, and one in the Laegieskamp (2013), all in the Netherlands.

Remarks: This species has never been recorded by Hoogenraad & De Groot (1940) for the Netherlands.

Placocista lens
Drawing Ferry Siemensma
Placocista lens
Penard (1905) in Les Sarcodines des Grands Lacs.
Placocista lens
Placocista lens, with real ‘rhizopodia’; note the broad aperture.
Placocista lens
Placocista lens
Placocista lens
Placocista lens
Placocista lens
Placocista lens
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