A new species of Trichodina lishuiensis n. sp. (Ciliophora: Trichodinidae) in urinary bladder of Odorrana schmackeri (Amphibia: Ranidae) from Zhejiang, China

Endoparasitic trichodinids are rather rare ciliates. In this study we describe a new species named Trichodina lishuiensis from the bladder of Odorrana schmackeri collected in Zhejiang, China, with the prevalence of 20% (9/ 45). We identified T. lishuiensis as a new species by morphological comparison and molecular analysis. The ciliates were observed using the dry-silver and protargol staining methods, as well as SEM (scanning electron microscopy). Trichodina lishuiensis is a small species (cell diameter 31.8-43.9 mu m), with incompact denticles connection, medium-wide blades and thick rays. We also sequenced a 1712 bp-long fragment of the small subunit ribosomal RNA gene (SSU rRNA). Phylogenetic analyses showed that the new species clustered with Trichodina unionis. The route of transmission of Trichodina species in the urinary bladder remains a mystery. We hypothesize that the transmisison takes place during the amplexus, with eggs and sperm discharged from the cloaca, and that trichodinids 'accompany' the amphibian through its whole life cycle, but further studies are needed to test this hypothesis.