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Vannella ebro Type strain CCAP 1589/1.

Olympus CK2, Phase contrast
Locomotive forms, nucleus. Note longitudinal ridges, rather common in this species

Vannella ebro Type strain CCAP 1589/1.

Olympus CK2, Phase contrast
Locomotive forms.

Photo: A.Smirnov

Basic references for identification:

  • Smirnov A.V. 2001. Vannella ebro n.sp. (Lobosea, Gymnamoebia), isolated from cyanobacterial mats in Spain. Europ. J. Protistol. 37: 147-153.
    Vannella ebro Smirnov 2001 CCAP 1589/1 (type strain)

  • Fan-shaped or semicircular vannella, with a tendency to form waves on the frontal hyaloplasm. Several short longitudinal ridges in some specimens. Length of the locomotive form on the plastic base of the Petri dish 25-40 mkm (average 30 mkm); breadth 35-60 mkm (average 41 mkm). Length/Breadth ratio 0.5 - 1.0.

  • Floating form variable, with 4-8 long, thick, tapering hyaline pseudopodia in fresh isolates, and without pseudopodia in older cultures.

  • Uninucleate, vesicular nucleus about 8 mm in diameter. Single, central, optically homogenous nucleolus about 4 mm in diameter (when measured in live specimens). No crystals in the cytoplasm. One or two large, distinctive vacuoles that do not contract normally present.

  • The question of cyst formation remains unresolved. In cultures, no cysts were observed despite numerous attempts to encourage amoebae to encyst by gradual drying of the culture and during salinity and oxygen tolerance experiments. However, during the work with initial cultures, on one occasion, amoebae which were left on a glass slide for several hours (in a moist chamber) formed rounded cysts -like bodies which appeared to have a single wall. No further attempts to reproduce this observation were successful.

  • Cell coat consisting of glycostyles, about 140 nm in length without accociated simple filaments.

  • Lives under oxygen concentration above 50 mkM and in the salinity range 6-90ppt. Feeds on bacteria, diatoms, algae and filamentous cyanobacteria. Marine, observed habitat: cyanobacterial mats in Ebro Delta (Spain), salinity 70-80 ppt.

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