A new species of Rhabdias (Nematoda: Rhabdiasidae), a lung parasite of Pristimantis chiastonotus (Anura: Strabomantidae) from the Brazilian Amazon: description and phylogenetic analyses

Rhabdias Stiles and Hassal, 1905 comprises approximately 90 species of parasitic lung nematodes of amphibians and reptiles that have a wide distribution, with 21 species occurring in the Neotropics. In the present study, we describe Rhabdias waiapi n. sp. found parasitizing the lungs of the anuran species Pristimantis chiastonotus from the Amazon Biome in the Amapá State, Northern Brazil. The new species is characterized by having an elongated body, expansions of the cuticular inflation in the anterior end that become more discrete along the body, an anterior end with a slight constriction at the level of the esophageal apex with four rounded subapical elevations of the body wall, six lips, four near the edge of the oral opening and two more distant lateral ones, and a gradually tapering elongated tail. In addition, molecular analyses and phylogenetic reconstructions were made, with sequences from the coding region of the mitochondrial cytochrome c oxidase subunit I gene. Those results strongly support the status of the new taxon, which formed a poorly supported clade with Rhabdias sp. 5 from Anolis brasiliensis from Northeast Brazil. Rhabdias waiapi n. sp. is the 19th species of the genus described in the Neotropics for amphibians, the 10th in Brazil, the second described from hosts of the family Strabomantidae from the Neotropical region, and the first amphibian nematode species described in the Amapá State.