Three new Loxophyllum species (Ciliophora: Pleurostomatida) from China with a brief review of the marine and brackish Loxophyllum species.

Recent studies indicate that there is a high diversity of pleurostomatid ciliates in the coastal waters of China. Here, three new congeners of Loxophyllum, L. caudatum sp. n., L. rugosum sp. n., and L. chinense sp. n., are described following observations of live cells and protargol-impregnated specimens. All three species usually have two macronuclear nodules and prominent warts along the dorsal margin formed by clustered extrusomes. In addition, L. caudatum sp. n. is characterized by its long conspicuous tail, dot-like cortical granules, 4 or 5 left and 9 or 10 right kineties, and a single subterminal contractile vacuole. Loxophyllum rugosum sp. n. is distinguished by possessing three prominent ridges on the left side, 7-11 right and 5-7 left kineties. Loxophyllum chinense sp. n. is characterized by having several contractile vacuoles distributed along the ventral margin, 13-18 right and 6-8 left kineties. The small subunit ribosomal DNA (SSU rDNA) sequence similarities among six congeners range from 96.46% to 99.94%. Phylogenetic trees based on the SSU rDNA sequences indicate that all Loxophyllum spp. form a well-supported monophyletic group. A brief review of the marine and brackish Loxophyllum species is supplied and one new combination, Litonotus multiplicatus (Kahl 1931) comb. n. (basionym Loxophyllum multiplicatum Kahl 1931), and one new name, Litonotus dragescoi nom. n. (basionym L. fasciolatus Dragesco 1966), are suggested.