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Family Vannellidae Bovee, 1970

Diagnosis: Amoebae have locomotive forms markedly flattened, fan-shaped, or linguiform with a prominent anterior hyaline zone without subpseudopodia. No posterior uroid. Floating form of most with radiating pseudopodia, either blunt or tapered. Nucleus of most with prominent central nucleolus, rarely with parietal lobes. Cytoplasmic crystals rare.
Glycocalyx of the only two genera studied by TEM differentiated into either pentagonal glycostyles (Vannella) or hexagonal arrangements (Platyamoeba).

Remarks: Family diagnosis emended by Page (1987) on the basis of this ultrastructural information. The present grouping of genera is based on morphological similarities at the LM level since ultrastructural details are unavailable for most.

 

1Hyaloplasm smooth2
 –Hyaloplasm with surface features3
2Hyaloplasm extends posteriorly as borderDiscamoeba
 –Hyaloplasm predominantly anteriorVannella
3Surface features faint4
 –Surface features obvious5
4Usually with faint longitudinal edge ridgesPlatyamoeba
 –Usually with faint lateral foldsClydonella
5Hyaloplasm with series of superimposed wavesUnda
 –Hyaloplasm with conoidal bossesPessonella
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