portrait

Description :

Portrait of the colorless metopid ciliate, Tropidoatractus acuminatus. The cell is elongate and slightly laterally compressed. The anterior end is rounded, the posterior drawn out into a short point. The pellicle is armored with prominent ridges, which spiral about the long axis of the cell. The sparse somatic cilia lie in the grooves between these ridges. The cytostome is anterolateral with perizonal stripe of longer cilia. There is an inconspicuous adoral zone of membranelles. The ellipsoid macronucleus is centrally located. Single micronucleus. Like many metopid ciliates T. atcuminatus has an accumulation of brownish refractile granules at the anterior end. There is a terminal contractile vacuole. T. acuminatus swims slowly spiraling on its long axis. Collected from sapropelic bottom sediment of dredge pond near Idaho city, Idaho September 2003. DIC optics.