Description of Euplotes

An iInflexible hypotrich, dorso-ventrally flattened, dorsally ridged, oval body with very large AZM usually extending at least two-thirds the body length. Common in freshwater and marine habitats. Marginal rows of cirri absent but usually there are 1 or 2 weak cirri on the left margin. There may be a lateral ciliary row on either side of the ventral surface. Large fronto-ventral and transverse cirri present. With 2-3 large (right) caudal cirri. Macronucleus C-, M- or horseshoe-shaped, with single adjacent micronucleus. First described by Ehrenberg (1831). Many species. One of the main morphological traits used for carrying out a preliminary species distinction is the type of argyrome shown by the cell on its dorsal surface. This term refers to the geometrical, meshwork-like structure which becomes apparent after the cell is silver-stained, and reflects lines of junction between the flat, polygonal alveoli. A division of Euplotes species into groups is often made on the basis of three basic argyrome types, each defined by the number of rows of polygons lying between any two adjacent kineties.There may be one, two, or more than two of these rows - allowing patterns to be classified as single, double, or multiple types.The double argyrome type typifies eurystomus and patella. The number and disposition of the ventral cirri and the geometry of the dorsal argyrome, have been regarded as being sufficiently clear and stable to justify some workers splitting this taxon into four morphologically distinct sub-genera, Euplotes, Euplotoides, Euplotopsis and Monoeuplotes