Abstract
Two marine stichotrich ciliates, Metaurostylopsis flavicana spec. nov. and Tunicothrix wilberti (Lin & Song, 2004) Xu et al., 2006, isolated from the Shenzhen Mangrove Protection Area on the coast of the South China Sea, were investigated using live observation and protargol impregnation techniques. Metaurostylopsis flavicana is characterized by its elongate body shape, yellowish body colour and bright-yellow cortical granules that are either grouped around the cirri and the dorsal cilia or aligned between the rows of cirri and dorsal cilia. It has four to eight frontal, two frontoterminal, one buccal and seven to ten transverse cirri, a mid-ventral complex comprising 13-17 midventral cirral pairs in a row that extends about three-fifths of the body length, four left and three right marginal rows and three complete dorsal kineties. The small subunit rRNA gene of this species was sequenced and phylogenetic trees were constructed in which M. flavicana does not group with its congeners, suggesting that the genus Metaurostylopsis is paraphyletic. Some supplementary morphological and morphogenetic traits for Tunicothrix wilberti are also documented.