Morphology and Molecular Phylogeny of Blepharisma hyalinum Perty, 1849 (Ciliophora, Heterotrichida) Isolated from Soil

In this study, two successive populations of Blepharisma were observed in cultures prepared from soil samples collected from Tekirdağ (Türkiye). The cells and cysts belonging to these populations were examined morphologically and morphometrically, and their phylogenetic positions were determined based on SSU rDNA gene sequences. Both populations were morphometrically very similar to each other, but population 1, the initial population observed in soil cultures, had a pyriform body that was inflexible and rigid while population 2, observed subsequent to the disappearance of population 1, exhibited a flexible, fragile, lanceolate body. In addition, the cell width/length ratios of both populations were found to be statistically different from each other. However, since the SSU rDNA nucleotide sequences of both populations are very similar to each other and to other B. hyalinum populations described previously, it is concluded that the observed Blepharisma populations represent different morphotypes of B. hyalinum. It has been hypothesised that the observed morphological differences may result from diet, environmental factors, and variations in the life stages of the cultured cells. Comparison of SSU rDNA nucleotide sequences of Blepharisma populations and phylogenetic analyses showed that the nucleotide sequences of some different species are identical or very similar. To clarify this chaotic situation, extensive molecular data based on detailed morphological studies on Blepharisma populations are necessary.