Life-History Traits and Genetic Characterization of Polystoma borellii (Monogenea, Polystomatidae), a Parasite of Pleurodema borellii (Anura, Leptodactylidae)

Abstract

The genus Polystoma includes parasites with direct life cycles that involve a shortlivedfree-living, aquatic oncomiracidia, post-larvae infecting the gill chambers of tadpoles,and adults parasitizing the urinary bladder of adult anurans. Despite the high diversityof anurans in the South American sub-continent, less than 20 species of Polystoma havebeen reported to date, and, particularly, in Argentina, only five species have been describedfrom adult frogs. The aim of this work was to describe and characterize taxonomicallythe specimens found parasitizing tadpoles and frogs living in a well in Chicoana, Saltaprovince, Argentina. Parasites were observed under optical and scanning electron microscopyand characterized genotypically by sequencing ITS1 and COI fragments. Frogsand tadpoles were characterized by morphology and sequencing a partial fragment ofthe cytochrome B region, confirming that the hosts corresponded to Pleurodema borellii.Given their morphology and the strict specificity of Polystoma species for their hosts, theidentity of the parasites was established as P. borellii. The morphology of oncomiracidiaand post-larvae was described, expanding adults? description with insights provided byCOI and ITS1 molecular analysis. The present work summarizes a complete description ofthe life cycle, with the genetic characterization of Polystoma borellii in Salta, Argentina.