portrait

Description:

Portrait of Platynematum sociale (Penard,1922) Foissner,Berger and Kohmann, 1994, a philasterine scuticociliate. P. sociale is the type species. Very similar in appearance to Cinetochilum. Ellipsoid in outline and dorsoventrally flattened and slightly arched. The somatic kineties lie between longitudinal pellicular ridges. There are short blunt posterior tooth-like projections. Kineties arch concentrically around the oral aperture in a horseshoe configuration. There is a long caudal cilium. Unlike Cinetochilum the inconspicuous oral aperture in P. sociale is subapical (right anterior in this image) rather than right posterior. A weakly developed undulating membrane and adoral membranelles are present (not seen in this image). The posterior macronucleus is spherical. The ventral contractile vacuole is located posteriorly. From freshwater pond near Boise, Idaho. DIC optics.