Two new species of polystomes (Monogenea: Polystomatidae) from the anuran host Guibemantis liber

Madapolystoma ramilijaonae n. sp. and Madapolystoma cryptica n. sp. (Monogenea, Polystomatidae) are described from the urinary bladder of disjunct populations of the Madagascar shrub frog Guibemantis liber. Although only minor morphological characters distinguish the new species from the single nominal species of the genus, i.e. Madapolystoma biritika, their strong and concordant differentiation in a mitochondrial and a nuclear gene supplemented by phylogenetic analyses indicates that M. ramilijaonae n. sp. and M. cryptica n. sp. should be regarded as two distinct species. Because anuran polystomes are known to be host-specific, the description of two cryptic species from a single host species points to a taxonomic complex situation in G. liber, a widespread frog that is characterized by the presence of several deep conspecific lineages and possibly by hybridization and admixture with other species of Guibemantis.