Marine 18-cirri hypotrichs with more or less distinctly narrowed (cephalized) anterior body portion and undulating membranes roughly in Stylonychia pattern. Distal portion of adoral zone far extending posteriorly. Most frontoventral cirri and postoral ventral cirri form median cirral row. One left and one right marginal row. Two extra cirri behind right marginal row. Three bipolar dorsal kineties. Caudal cirri present. Adoral zone of proter composed of newly formed proximal and central portion and parental distal portion. Frontal-ventral-transverse cirri originate from anlagen IâVI. Dorsal morphogenesis in Gonostomum-pattern, that is, intrakinetal proliferation within all parental rows; kinety fragmentation and dorsomarginal kineties lacking. Type species: Oxytricha (Tachysoma) rigescens. Kahl, 1932. (from
Li et al., 2010. Acta Protozoologica, 49: 195-212).
