Morphology and morphometry of Bresslauides pratensis n. sp., a new soil ciliate (Ciliophora, Colpodea) from Turkey.

A new colpodid ciliate, Bresslauides pratensis n. sp., was discovered in soil from a meadow field in Turkey. Its morphology was investigated using live observation, protargol impregnation, silver nitrate impregnation, and scanning electron microscopy. The new species differs from the congeners by the following combination of features: the cell size in vivo is about 135-180 μm × 130-160 μm; the body has an almost circular outline with a conspicuous bulge on the ventral side; the somatic cilia are arranged in about 105 densely spaced, sigmoidal kineties; a diagonal groove extends to the left cell side, terminating in a pronounced postoral sack; one almost globular macronucleus and usually two globular micronuclei; the oral structures occupy almost the anterior half of the cell and comprise a distally elongated right polykinetid and a crescentic left oral polykinetid, both restricted to the vestibulum; on average 12 vestibular, 31 postoral, and 55 left oral kineties. Based on the morphological data, it was concluded that B. pratensis is a well-outlined and distinctive member of the genus Bresslauides. Additionally, the most recent molecular data on the order Colpodida and genera Colpoda, Bresslaua, and Bresslauides are briefly discussed.