The phylogenetic position of the unusual diplostomoidean genusVigueras, 1941 (Digenea, Diplostomoidea) and description of 2 new species from Neotropics.

Abstract

Vigueras, 1941, is a small, rarely reported genus of diplostomoideans that parasitize avian definitive hosts, predominantly anhingas, on several continents. No DNA sequences were previously available for anyspp. In the present study, we describe adults of 2 newspp. from anhingas in Brazil. We also provide description of metacercaria of one of the new species from Argentina.n. sp. lacks a clear separation between its testes, appearing almost as a contiguous, irregularly shaped, lobular mass. A highly characteristic feature ofn. sp. is a strongly enlarged lobe of the holdfast organ. These features, along with distribution of vitellarium and nature of the preputial folds surrounding the genital cones, separate the new species from their congeners. We generated partial sequences of the large ribosomal subunit (28S) rDNA and cytochrome c oxidase subunit I (1) mtDNA genes from adult forms of both species and1 of metacercarial stages. The 28S sequences were used for phylogenetic inference. The pairwise sequence divergence between the 2 species is 4.0-4.6% in1 gene. Intraspecific variability in the same1 region did not exceed 0.8% despite the long geographic distance between collecting sites in Brazil and Argentina.