Euplotes rariseta curds et al. (ciliophora hypotrichida) from the Somalian coast: Description and preliminary observations on cyst induction and ultrastructure

Abstract

The Euplotes studied were assigned to E. rariseta Curds et al. (Ciliophora Hypotrichida) morphotype despite significant differences in some diagnostic traits. They carry seven kineties instead of six and more kinetosomes in each kinety. In addition, they were found capable of encysting under controlled conditions. Cyst formation was induced by exposing cells to environmental salinities 2::: 52%o. Encystment mainly involves rounding of the body shape with retainment of approximately only 20% of the vegetative cell volume, complete loss of several frontoventral cirri, and partial degeneration of the other ciliary organelles. Cysts appear surrounded by amorphous protective material, show the persistent cilia closely packed and frequently fused in pairs to form a kind of ciliary syncythia, and contain a macronucleus with a rarified nuclear pore density. © 1987 Taylor & Francis Group, LLC.