A new genus of Carnoyidae (Nematoda: Rhigonematida) with descriptions of Cattiena trachelomegali gen. n., sp n. and C-trigoniuli gen. n., sp n., parasites of Spirobolida (Diplopoda) from Vietnam

Cattiena gen. n., a new genus from the Carnoyidae, is described from the posterior gut of two genera of spirobolid diplopods from Vietnam. The new genus is characterised by: presence of eight somatic spine rows in the cervical region of both male and female. the four sublateral spine rows being better developed presence of six cuticularised plates around the female oral opening: extremely posterior vulva: two anteriorly directed ovaries; isomorphic and isometric spicules: boat-shaped gubernaculum of similar form to the spicules; gubernaculum with a dorsal hole, well developed, smooth cephalic cap in the male and 15 copulatory papillae with three pairs located lateral, sublateral or subdorsal. The new genus has morphological affinities with Raonema Moss, 1965, a poorly known genus from India, but is easily differentiated by the extremely posterior vulva and the presence of spine rows in the male. Two new species are described in the genus: the type, C. trachelomegali gen. n., sp. n. from Trachelomegalus sp. and C. trigoniuli gen. n., sp. n. from Trigoniulus sp. The two species differ primarily in the position of the vulva (consistently more anterior in the latter species). degree of development of the vulval flap, body length, tail length and in the relative development of the somatic spine rows.