A new species of Aplectana Railliet & Henry, 1916 (Nematoda: Cosmocercidae), a parasite of Leptodactylus bolivianus (Anura: Leptodactylidae) from the southern Peruvian Amazon, including molecular data

Abstract During a helminthological survey conducted in the southern Peruvian Amazon, nematodes representing an undescribed species of Aplectana Railliet & Henry, 1916 (Cosmocercidae) were recovered from the intestine of Leptodactylus bolivianus Boulenger, 1898 (Anura: Leptodactylidae). The new species, Aplectana peruensis n. sp., is described herein based on an integrative taxonomic approach combining detailed morphological analysis using light and scanning electron microscopy with molecular characterization of the partial 18S rDNA gene. Aplectana peruensis n. sp. is distinguished from its congeners by a unique combination of characters, including 13 pairs of caudal papillae (3 precloacal, 5 adcloacal, and 5 poscloacal papillae) plus a single unpaired papilla, the presence of a gubernaculum, and relatively long spicules (152–194) with a clearly defined distal bifurcation. Phylogenetic analyses based on Bayesian inference methods recovered the new species as a well-supported sister lineage to A. hylambatis (Baylis, 1927) from the Neotropical region. Genetic divergence values further support its specific distinctiveness. This study represents the first description of an Aplectana species from L. bolivianus in the Amazon region of Peru and increases the number of recognized species within the genus.