Skrjabinodon castillensis n. sp. (Nematoda:Pharyngodonidae) from the Homonota horrida and H.darwinii (Squamata: Phyllodactylidae) from Argentina and key for the Neotropical species of the genus Skrjabinodon.

Skrjabinodon castillensis n. sp. is described and illustrated here, based on specimens found in the large intestines of Homonota horrida (province San Juan) and Homonota darwinii (province Neuquén) (Squamata: Phyllodactylidae) from Argentina. The new species is assigned to Skrjabinodon based lateral alae present in males, absent in females. Lateral alae beginning midway between lips and nerve ring and ending just posterior to first pair of caudal papillae. Females with vulva near esophageal bulb. In males, caudal alae absent, paired caudal papillae present. Skrjabinodon castillensis n. sp. represents the 9th species from the Neotropical realm. The new species differs from all other species assigned to Skrjabinodon by morphology of tail filament and number of tail filament spines. Skrjabinodon castillensis n. sp. is the only species of this genus known from Argentina. A key to the species of Skrjabinodon in the Neotropical realm is provided.