Sphaerophrya infesting Bursaria

Description:

Image of the stalkless parasitic suctorian, Sphaerophrya insolita (Jankowski, 1973) infesting the large colpodid ciliate, Bursaria truncatella (Muller, 1773). The Sphaerophrya cells are ellipsoid and approximately 35 u in diameter. One suctorian can be seen adhering to the right lip of the vestibulum of the host cell. At least 7 others can be seen adhering to the pellicle where they may be mistaken for food vacuoles on cursory examination. Sphaerophrya is thought to have lost its stalk during the transition to a parasitic mode of existence. The cells have capitate tentacles by which they adhere to the pellicle of the host cell. There is a central ellipsoid granular nucleus (the micronuclei have not been characterized). There is a single peripheral contractile vacuole. These individuals were found on B. truncatella collected from a temporary rainwater pool containing decaying grass near Boise, Idaho March 2005. DIC.