world of amoeboid organisms

Arcella lobostoma
Arcella lobostoma, after Deflandre, 1929

Arcella lobostoma Deflandre, 1929

Diagnosis: Shell hemispherical. In ventral view, irregular circular outline, often a little elliptical; pseudostome irregularly lobed: four more or less deep, rounded or slightly angular lobes, connected by pointed or blunt teeth. In lateral view, the dorsal region is semi-circular; the angle of connection with the ventral side is widely rounded. Aperture slightly invaginated, without buccal tube. Membrane yellow-brown or less dark, with fine areolation, easily visible, often provided with some irregular undulations or dimples.

Dimensions: Diameter 42-54 µm, height 29-32 µm; apertural length and width vary between 9 and 18 µm;  buccal depth 5.5 to 7.0 um. H/D ratio 0.65 to 0.68.

Ecology: Freshwater. Aaquatic species coming from a siliceous pond, in the company of desmids. Geographical distribution: Venezuela.

Ferry Siemensma, created January 23, 2021; last modified January 31, 2021
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