portrait

Description:

Portrait of the hymenostome ciliate, Frontonia acuminata (coronal optical section). F. acuminata is dorsoventrally flattened. The cell outline is broadly ellipsoid, tapering very slightly posteriorly. F. acuminata has a small cluster of dark brown cytoplasmic granules anteriorly (the similarly shaped F. angusta lacks such granules and is less flattened). The oral aperture is roughly triangular with the base posterior and the anterior apex terminating at a thin preoral suture. There is an undulating membrane on the right and three adoral membranelles on the left. There is a narrow postoral suture to the right of which lie prominent vestibular ciliary rows and to the left of which lie postoral kineties. The round macronucleus is seen here anteriorly with the prominent micronucleus indenting the left margin. Numerous extrusomes form a peripheral fringe(extrusomes seen here posterior and left of oral aperture). The single contractile vacuole is subequatorial. Probably omnivorous. Collected from a slow-moving freshwater stream near Boise, Idaho in July 2003. DIC optics.