Aonchotheca musimon n. sp. (Nematoda : Capillariinae) from the mouflon Ovis musimon in the sub-antarctic Kerguelen archipelago, with comments on the relationships with A. bilobata (Bhalerao, 1933) Moravec, 1982 and other species of the genus.

An intestinal capillariid nematode, Aonchotheca musimon n. sp., is described from Ovis musimon imported into the Kerguelen archipelago (Terres Australes et Antarctiques Françaises). The comparison of this new material with other Aonchotheca spp. is based on the usual characters, i.e. spicule, caudal bursa, number of papillae, stichosome, bacillary bands, shape of the cirrus, and on the length of the ejaculatory duct which appears to be of some phylogenetic value. A. musimon, of which the spicule is 208-230 microm long, is close to A. bilobata, another parasite of bovids, which is redescribed here. It is distinct from this species because the posterior region of the female worm is cylindrical instead of conical, the lateral alae of the male worm are longer, quadrangular and vesicular instead of triangular and smooth, the caudal bursa has a folded dorso-lateral edge, there is a recurrent ventral fold of the cirrus, the slender distal part of the spicule is longer, the oesophagus is shorter in both sexes and the slightly larger eggs have a thicker shell. These two species from bovids and A. murissylvatici from murid rodents, of which the main characters are similar, represent a small group with a very elongate ejaculatory duct (1.9-2.5 mm). This is in contrast to a larger group of species with a short ejaculatory duct (350-600 microm), which are parasites of Chiroptera (A. brosseti, A. chabaudi, A. landauae, A. gabonensis), Insectivora (A. erinacei), mustelid Carnivora (A. putorii, A. mustelorum) and glirid rodents (A. myoxinitelae, A. legerae). A. bovis and A. dessetae, respectively parasites of bovids and lagomorphs, present an ejaculatory duct of intermediary length and do not belong to these groups. Several species are transferred to the genus Aonchotheca: A. kashmirensis (Raina & Kaul, 1982) n. comb., A. legerae (Justine, Ferté & Bain, 1987) n. comb., A. forresteri (Kinsella & Pence, 1987) n. comb., A. chabaudi (Justine, 1989) n. comb., A. landauae (Justine, 1989) n. comb., A. brosseti (Justine, 1989) n. comb., A. gabonensis (Justine, 1989) n. comb. and A. dessetae (Justine, 1990) n. comb.