Polystoma knoffi n. sp. and Polystoma travassosi n. sp. (Monogenea: Polystomatidae): naming museum-archived specimens from Brazil.

In 1978, Kohn and co-workers deposited several polystome (Monogenea) specimens infecting several Brazilian anurans [Trachycephalus mesophaeus (Hensel), T. nigromaculatus Tschudi and Leptodactylus pentadactylus (Laurenti)] within the Helminthological Collection of the Instituto Oswaldo Cruz, Brazil. No specimen was formally described but we herein identified three morphotypes and formally describe two of them (Polystoma knoffi n. sp. and P. tavassosi n. sp.). These are respectively the 12th and 13th species of Polystoma described from South America. For both species, the intestine forms a reticulated network, a characteristic unique to most Neotropical species of Polystoma.