A new species of lungworm from the Atlantic Forest: n. sp. parasite of the endemic anuran .

are lung-dwelling parasites of anurans and some reptiles. Currently, 93 species are known to exist worldwide. The identification of species is based mainly on morphological traits of hermaphroditic females that generally have a very conserved morphology. However, different approaches, such as the combination of morphological, molecular, and ecological data, have provided advances in identifying and delimiting rhabdiasid species. Here, we describe a new species of from the south of Brazil, with morphological and molecular data. The new species is distinguished from its congeners by having an elongated body, evident cephalic dilation, larger buccal capsule, and large esophagus. In addition to morphological characteristics, we observed significant genetic divergence among the cytochrome oxidase subunit I (COI) sequence of the new species and the closest available sequence, (10.24%-10.87%). Furthermore, phylogenetic reconstructions based on the COI gene indicated that the new species represents a different lineage, constituting an outgroup of the species complexes cf. and with sp. 4. Thus, is the 24th nominal species of the Neotropical region, the 14th Brazilian, and the fourth species described from south of Brazil.