Unveiling the evolutionary pathways of Ochoterenella: a new species discovery and its phylogenetic implications.

Ochoterenella is a large group of filarial parasites of anurans distributed throughout Central and South America. In the present study, we describe a new species of Ochoterenella parasitizing 2 frogs, Boana geographica and Boana multifasciata, from different localities in the Brazilian Amazon. The main morphological traits that differ Ochoterenella casiraghii n. sp. from its congeners are the smaller body size, a shorter cephalic plate, smaller parastomal structures, and the small, short and rounded cuticular bosses on the body of both sexes. The females have a shorter ovejector, and the number of caudal papillae distinguishes males. Pairwise sequence comparisons of the new species reveal a high level of divergence from Ochoterenella spp. Our phylogenetic analyses, based on cox1 and concatenated partial mitochondrial genes, support the monophyly of all subfamilies and genera examined herein. The new species represents the 17th in the Ochoterenella genus and a new parasite record for both anuran species. We provide the first ultrastructural description of the species in the genus and establish the phylogenetic relationships of the new species among parasites of amphibians and reptiles from the Onchocercidae.