Abstract
The morphology and infraciliature of three marine ciliates, Frontonia didieri n. sp., F. multinucleata n. sp. and F. tchibisovae, isolated from northern China seas, were investigated using living observation and silver impregnation methods. Frontonia didieri n. sp. is recognized by: in vivo ca. 100-150 x 45-80 mu m; 61-71 somatic, 3 vestibular and 3-5 postoral kineties; 4-rowed peniculus 1 and 2; peniculus 3 three-rowed; contractile vacuole centrally-located, with about eight conspicuous collecting canals. Frontonia multinucleata n. sp. is characterized by: 70-120 x 40-75 mu m in vivo, dorsoventrally flattened about 2: 1; 58-67 somatic, 3 vestibular and 4-5 postoral kineties; 3 peniculi each with 4 kineties; 2-4 globular macronuclear nodules; contractile vacuole located in posterior 1/3 of cell length. Based on both original and the Qingdao population, the poorly-defined Frontonia tchibisovae is redefined and a new diagnosis is supplied.