Pseudoamphisiella alveolata (Kahl, 1932) nov comb., a large marine hypotrichous ciliate from China (Protozoa, Ciliophora, Hypotrichida)

The hypotrichous ciliate Pseudoamphisiella alveolata (Kahl, 1932) nov, comb. (formerly Holosticha alveolata Kahl, 1932), a poorly-known, marine organism with a unique alveolar covering on the cell surface, was isolated from coastal waters off Qingdao (Tsingtao), People's Republic of China. Its morphology and infraciliature were investigated and described from organisms observed in vivo and following protargol silver impregnation. Based on these observations, an improved diagnosis for this species is presented: slightly contractile, marine Pseudoamphisiella, in vivo 120-240 mu mx50-80 mum with 2 macronuclei and conspicuous bar-like extrusomes within an alveolar covering on the cell surface. On average, 50 adoral membranelles; 3 frontal and 2 buccal cirri; two well separated ventral rows, each with about 12 cirri; 12-16 transverse cirri extending about 2/5 of cell length; 14-20 and 12-14 cirri in left an right marginal rows respectively; 11-16 caudal cirri which connect the left and right marginal rows completely; 10-12 dorsal kineties. Based mainly on its ciliature, P. alveolata is compared with its only known congener, P. lacazei (Maupas, 1883). The systematic position of the morphologically similar Keronopsis macrostoma Dragesco, 1963 is also briefly discussed, and is here synonymised with P. lacazei.