摘要

A population of the marine euplotid ciliate, Uronychia multicirrus Song 1997, found in the littoral zone of the Daya Bay, Guangdong, South China, was investigated using live observation and protargol impregnation method. This species is diagnosed by possessing a long row of ventral cirri, which has never been seen in all other known congeners. Divisional process, described based on protargol-impregnated specimens, is typical of the genus regarding its general pattern: (1) the oral primordia in both proter and opisthe develop de novo in two subcortical pouches, while the UM-anlage forms de novo (i.e. does not develop from the oral primordium); (2) five frontoventral-transverse (FVT)-cirral anlagen develop in a primary-mode on the cell surface, and almost all the cirri are derived from the FVT-anlagen, except the first frontal cirri, which are formed de novo in both dividers; (3) the species characteristic ventral row derives from the right-most FVT-anlage; (4) the parental structures do not take part in the construction of the marginal anlagen, and (5) the caudal cirri originate in the right-most two dorsal kineties in a multi-segmentation mode. The small subunit rRNA gene of U. multicirrus (GenBank accession number: EU267929) is 1,773 bp and differs by 0.9-1.41% from its closely related congeners.