in vivo, ventral view

Image of Nassophorea


Ventral view of the nassulid ciliate, Furgasonia trichocystis (Stokes, 1894) Jankowski, 1964. Synonym: Cyclogramma. The cell shape is a slightly dorsoventrally flattened ellipsoid. The left side is flattened and the right side slightly convex. The cytostome is in the anterior 1/5 of the cell in a shallow depression. It is supported by a prominent basket of obliquely oriented cytopharyngeal trichites. The somatic ciliature consists of about 32 to 26 longitudinal kineties. On the ventral surface the right kineties arch to the left anterior to the cytostome to terminate on a short but wide preoral suture. The straight left kineties terminate on this suture to the left of the cytostome. There is a short curved right paraoral membrane. There are three approximately rectangular paroral polykineties. The most anterior (M1) is also least conspicuous. It is obliquely oriented in the preoral suture. The middle membrane (M2) is to the left of the cytostome and almost perpendicular to the long axis of the cell. The most posterior membranelle (M3) is posterior to the cytostome (often obscured by the trichites in silver carbonate preparations) almost parallel to the long axis of the cell. These three distinctive small polykineties distinguish Furgasonia from other nassulid genera. The spherical macronucleus and adjacent micronucleus are slightly posterior to the equator. The single contractile vacuole (visible here posterior to the cytopharyngeal basket) is located in the cell center with an excretory pore on its ventral aspect. There is a prominent layer of fusiform subpellicular extrusomes (mucocysts). The cytoplasm is colorless in these bactivorous individuals. It is unclear whether this species is synonymous with F. rubens which is orange to blue colored due to ingested cyanobacteria. Morphologically the two species are quite similar aside from this coloration (see Faur�-Fremiet, E. Le Genre Cyclogramma, Perty, 1852. J. Protozool. 14: 456-464, 1967.) Collected from a temporary rainwater pool with abundant decaying grass near Boise, Idaho. March, 2005. DIC. 

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William Bourland
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