Fine-tune investigations on three stylonychid (Ciliophora, Hypotricha) ciliates

The morphology and morphogenesis of two stylonychid ciliates, Stylonychia ammermanni Gupta et al., 2001 and Tetmemenabifaria (Stokes, 1887) Berger, 2001, isolated from soil samples of Lombardia region, Northern Italy, and water samples fromCheonggancheon stream, South Korea, were investigated. The Italian population of S. ammermanni was found to be very similarin morphology to the Indian type population and the junior synonym S. harbinensis Shi and Ammermann, 2004 since most ofthe morphometric data overlapped. On the contrary, the Korean population of S. ammermanni showed some non-overlappingdifferences in ciliature suggesting a separation at subspecies level, i.e., S. ammermanni ammermanni and S. ammermannikoreana nov. subspec. Furthermore, the resting cyst of the Italian population of S. ammermanni has many ring-shaped structureson the surface which, however, were not observed in the Korean population. Phylogenetic analyses based on the SSU rRNA genesequences show that the Italian and Korean populations of S. ammermanni fit well into the S. mytilus complex and moderatelysupport the subspecies separation. Additionally, we split Tetmemena bifaria into two subspecies, viz., T. bifaria bifaria and T.bifaria minima nov. subspec. based on differences in the number of adoral membranelles and number of cirri in the marginalrows of the Italian and the Argentinian populations in comparison with the populations described by Wirnsberger et al. (1985).