Genus Pellita Smirnov and Kudryavtsev, 2005

 

Diagnosis: Cell coat envelops the entire cell and is integrated with the cell membrane. For locomotion and phagocytosis amoebae produce short subpseudopodia protruding through the cell coat and covered at the distal end solely by the cell membrane. Flattened amoebae, from rounded to spatulate. Locomotive cell moves as a whole, without distinct pseudopodia. The cell coat consists of a fuzzy fibrous basal layer, covered with a layer of glycostyles. Each glycostyle is formed of five fine columns that widen distally to tubular tips, where they link in a pentagonal array.
Type species: Pellita catalonica

 

Pellita catalonica Smirnov and Kudryavtsev, 2005

 

Diagnosis: Locomotive form about 20 µm long (measured range 10-33 µm, mean 19.8 µm), and about 15 µm broad (7-25 µm, mean 15.2 µm), average length/breadth ratio 1.2 (range 1.0-1.9). Mononucleate, nucleus ovoid, 4-6 µm in maximal dimension, with several peripheral nucleoli. Cell coat about 500 nm thick, with a basal fuzzy fibrous layer about 100-120 nm thick, and the glycostyles making up the rest.

Ecology: Marine, found in cyanobacterial mats in the Ebro Delta (Catalonia, Spain), salinity 70-80%. Also found in sandy sediments of the shallow-water Niva Bay, Denmark, average salinity about 15%.

Remarks: Resembles with the lightmicroscope a member of the genus Paragocevia, but differs from it because the cell coat envelops the entire cell. Can be easily distinguished by electron microscopy from the unique structure of the cell coat. May be confused with Vannella, but clearly differs by the presence of short projections on the ventral surface of the cell and by the structure and thickness of the cell coat.

 

Pellita digitata (Greef, 1866) Smirnov and Kudryavtsev, 2005

Diagnosis: Locomotive form about 85 µm long (measured range 54-106 µm, mean 84.5 µm) and about 80 µm broad (54-115 µm, mean 81 µm), average length/breadth ratio 1.06 (range 0.75-1.38). Mononucleate, nucleus rounded, vesicular, 10-14 µm in diameter (average 12 µm). Single central nucleolus 5-7 µm in diameter (average 5.7 µm). Cell coat about 850 nm thick, of which the basal fuzzy fibrous layer makes up about a half; the rest formed by glycostyles.

 

Ecology: Freshwater, in aquatic mosses in Great Britain (Cash and Hopkinson 1909); Lake Leman, Switzerland (Penard 1902), and North-Western Russia.

 

Remarks: Resembles a member of the genus Paragocevia or (to a lesser extent) Cochliopodium, but differs from both because the cell coat envelops the entire cell. May be confused with Vannella, but clearly differs by the presence of short projections on the ventral surface of the cell and by the structure and thickness of the cell coat. Differs from P. catalonica in cell size and thickness of the cell coat.