Cochliopodium minutoidum Kudryavtsev, 2006

Diagnosis: Length in locomotion 8.4-19.5 um (average 14 um), breadth, 9.3-24 um (average 17.3 µm), length : breadth ratio, 0.58-1 (average 0.83). Oval to triangular; wide, uneven hyaloplasmic veil with numerous waves and subpseudopodia; few short trailing filaments. Spherical vesicular nucleus, 2.8-4.7 µm in diameter (average 3.7 µm), with large central nucleolus, 1.4-2.3 µm in diameter (average 1.8 µm). Occasionally 2-3 nuclei. Scales consist of a circular base plate with a square mesh grid pattern, a central column of four stalks, converging towards the top; funnel-shaped apical part consists of 14-17 radial spokes and numerous thin concentric rings. Diameter of the base plate, 0.49-0.63 µm (average 0.56 µm), of the apical part, 0.47-0.6 µm (average 0.54 µm), height of a scale 0.26-0.3 µm.

Ecology: Freshwater; bank of the Saba river, Leningrad Region, North-Western Russia, wet moss Aulocomnium sp. and organic matter from dead spruce trees (Picea sp.).

Remarks: In the general pattern of the scale C. minutoidum is similar to C. barki, C. actinophorum and C. minus. Differs from C. barki in having smaller scales with fewer spokes in the apical part, size of the locomotive form, broader hyaloplasmic veil, fewer trailing filaments and lack of the layer of refractile granules around the nucleus; from C. actinophorum, in the size and proportions of the scales, size of the locomotive form, presence of subpseudopodia in locomotion and lack of the layer of refractile granules around the nucleus; from C. minus, in the apparent presence of hyaloplasm at the posterior margin of the cell, the proportions of the scales and the structure of their central columns.

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