Abstract
One new genus and two new species of hypotrich ciliates isolated from brackish-water habitats in China were investigated. The new genus Polystichothrix gen nov. is defined by having a continuous adoral zone and more than 18 frontal-ventral-transverse cirri; undulating membranes in Oxytricha-pattern; three clearly differentiated frontal cirri; frontal and ventral cirri aligned in rows; one marginal cirral row on each side of the cell; more than three dorsal kineties; buccal cirrus and transverse cirri present. Polystichothrix monilata sp. nov. can be recognized by having a citrine-brownish cell colour caused by its citrine-yellow cortical granules; two frontal rows with a frontoventral cirrus to the left of them; four or five postoral ventral cirri; four or five short ventral rows; five dorsal kineties; about eight moniliform macronuclear segments. Lamtostyla ovalis sp. nov. is characterized by an ovoidal, flexible body; an amphisiellid median cirral row comprising about 11 cirri; about four frontoventral cirri; two pretransverse ventral and five transverse cirri; three dorsal kineties. We also provide the first record of the small subunit ribosomal RNA gene sequences for the genera Lamtostyla and Polystichothrix gen. nov. Phylogenetic analyses show that Pol. monilata sp. nov. is a member of the family Oxytrichidae, and that L. ovalis sp. nov. should be assigned to the family Amphisiellidae, although neither family is monophyletic. (C) 2017 The Linnean Society of London, Zoological Journal of the Linnean Society, 2017