Helminthoxys abrocomae n. sp (Nematoda : Oxyurida) from Abrocoma cinerea in Bolivia

A new pinworm parasite is described from Abrocoma cinerea, a caviomorph rod ent of the superfamily Octodontoidea from the Andes of Bolivia. The new spe cies, Helminthoxys abrocomae n. sp., possesses special secretory mamelons w hich we consider a synapomorphy of the genus Helminthoxys. Within Helmintho xys, the closest relatives are found in octodontoid rodents: H. gigantea oc curs in Octodon degus in Chile and O. bridgesi in Argentina, and H. freitas i is a parasite of Thrichomys aperoides in Brazil. H. abrocomae n. sp. diff ers from both other species morphometrically in relation to different parts of the body in both sexes, particularly the size of the body, spicule, gub ernaculum and eggs, by the presence of a rough cuticular area around the ce phalic sensory papillae and by the possession of very well-developed cervic al alae which are strongly curved dorsally. H. abrocomae n. sp. is the tent h nominal species described in Helminthoxys, all of them being parasites of caviomorph rodents.