n. gen., n. sp. (Nematoda: Cosmocercoidea: Atractidae) parasite of yellow-spotted Amazon river turtle, Troschel (Testudines: Podocnemididae) in Brazilian Amazon.

Nematodes collected from the stomach of the yellow-spotted turtle Troschel, 1848 (Testudinidae) in the Brazilian state of Pará are assigned to a new genus, allocated to the family Atractidae (Cosmocerdoidea). n. gen. differs from all other genera of Atractidae based on the combination of the following morphological characters: cephalic extremity surrounded by eight bifurcated, wrench-shaped sclerotized structures arranged in a circle; oral opening encircled by two sclerotized pieces with pointed ends and a median portion with a pair of hooks; in males the larger (left) spicule is narrower in the middle third and the gubernaculum is absent. The type species, n. gen., n. sp., has nine pairs of caudal papillae and a single papilla anterior to the cloacal lip. The new species is the seventh record of an atractid genus parasitizing .