Parabirojimia multinucleata spec. nov. and Anteholosticha scutellum (Cohn, 1866) Berger, 2003, marine ciliates (Ciliophora, Hypotrichida) from tropical waters in southern China, with notes on their small-subunit rRNA gene sequences.

Few studies using modern methods have been carried out on ciliated protozoa in tropical marine waters. In the present work, two hypotrichs, Parabirojimia multinucleata spec. nov. and Anteholosticha scutellum (Cohn, 1866) Berger, 2003, collected from Daya Bay in southern China, were investigated morphologically. P. multinucleata is distinguished by the following combination of characters: slender body, without a snout-like protrusion in the frontal field, and about 50 macronuclear nodules. The poorly known A. scutellum has never been investigated using modern methods; hence, a redescription is needed. During the present study, observations of specimens in vivo and following protargol impregnation revealed new information concerning structures such as the cortical granules and the infraciliature. A redescription and improved diagnosis are supplied based on the China population. The small-subunit (SSU) rRNA gene was sequenced for both organisms and comparisons with those of similar congeners clearly support the findings based on morphological studies.