Phylogeny and systematic revision of the family Pseudokeronopsidae (Protista, Ciliophora, Hypotricha), with description of a new estuarine species of Pseudokeronopsis

Chen, X., Clamp, J. C. & Song, W. (2011). Phylogeny and systematic revision of the family Pseudokeronopsidae (Protista, Ciliophora, Hypotricha), with description of a new estuarine species of Pseudokeronopsis. -Zoologica Scripta, 40, 659-671. The family Pseudokeronopsidae is a taxon of hypotrich ciliates with a history of uncertainty regarding its systematic and phylogenetic relationships to other members of the order Urostylida. Phylogenetic analyses of pseudokeronopsids were made using all available molecular and morphological information, and the patterns of morphogenesis of the group were reinvestigated. Results clearly demonstrated that the genera Thigmokeronopsis and Apokeronopsis are not confamilial with Pseudokeronopsis and Nothoholosticha but, instead, must be transferred to the family Urostylidae. A new estuarine species, Pseudokeronopsis erythrina sp. n. was discovered and described using a combination of morphological and molecular characters. Species of Pseudokeronopsis are difficult to characterize but can be distinguished from one another by a combination of morphological and morphogenetic characters. Pseudokeronopsis similis is a freshwater species that has significant morphogenetic differences with other members of the genus and may not be congeneric with them.