Morphology and molecular phylogeny of a new brackish pleurostomatid ciliate, Loxophyllum paludosum sp. n. (Ciliophora, Litostomatea, Haptoria), from a mangrove wetland in China.

A new ciliate species of the genus Loxophyllum Dujardin, 1841, Loxophyllum paludosum sp. n., is described from a mangrove wetland near Daya Bay in Guangdong Province, southern China, based on morphological and molecular analyses. The new species can be distinguished from its congeners by a combination of the following characters: (1) 12-14 right kineties and 4-6 left kineties; (2) two macronuclear nodules and one micronucleus; (3) a single contractile vacuole located terminally; (4) extrusomes bar-shaped, evenly spaced along entire ventral margin, and clustered to form 5-7 warts along dorsal margin; and (5) presence of three ridges on the left side of cell. The new species is divergent from its congeners from 0.4% to 6.7% (5-104 nucleotide sites) based on the small subunit (SSU) rRNA gene sequence data. The validity of the new species is also supported by molecular phylogenetic trees inferred from SSU rRNA gene sequences.