Polystoma luohetong n. sp. (Monogenea: Polystomatidae) from Rana chaochiaoensis Liu (Amphibia: Ranidae) in China.

Polystoma chaochiaoensis from the urinary bladder of the chaochiao frog Rana chaochiaoensis Liu was briefly described in a symposium abstract and presented at the Third Symposium on Parasitology of China in 1990. Types were not assigned and the original specimens collected are no longer available. The morphological description was incomplete and no illustrations were provided. We consider Polystoma chaochiaoensis a nomen nudum and provide a full description for the species and assign types. Based on morphological characteristics and molecular data of partial 18S rDNA sequences, we describe this species as Polystoma luohetong n. sp. Out of 578 frogs examined, 16 male and 38 female frogs were infected (prevalence 9.3%; mean intensity 1.02). Polystoma luohetong n. sp. is distinguished from all other Polystoma species by the presense of a prominent crest on the hamulus as well as by the shape and size of marginal hooklets and the intestinal arrangement. Furthermore, the phylogentic analysis based on the 18S rRNA gene shows Polystoma luohetong n. sp. well nested within the Ploystoma clade and as a sister taxon to Polystoma integerrimum.