Five new species of Rhigonema are described and illustrated from the gut of diplopods collected from the Philippines and Vietnam. R. flabellifer sp. n., R. golovatchi sp. n., R. rigonanae sp. n., R. spiridonovi sp. n. and R. voratum sp. n. are differentiated from one another and the remaining species in the genus by a combination of characters including form of the cephalic extremity, development and extent of the pilose region, female genital tract type, male and female tail shape, spicule form and number and disposition of the copulatory papillae. Two species, both from polydesmid diplopods, bear an unusual pedunculate, flap-like projection on each sector of the triangular oral aperture and have only thirteen copulatory papillae. Such projections have only previously been described from R. lanceacauda, a species from the West Indies that also shares a reduced and similarly arranged complement of thirteen male papillae. The morphology, bionomics and distribution of Rhigonema are discussed and evidence presented for the first time that nematophagy is practised by at least one species in the genus. Rhigonema leonilae (Sanchez-Velazquez, 1979) comb. n. is proposed for Ruizia leonilae Sanchez-Velazquez, 1979. Cinq nouvelles especes de Rhigonema Cobb, 1898 (Rhigonematida: Rhigonematidae) des Philippines et du Vietnam et observations sur la morphologie des formes indo-malaises et la nematophagie chez R. voratum sp. n. - Cinq nouvelles especes de Rhigonema provenant des intestins de diplopodes collectes aux Philippines et au Vietnam sont decrites et illustrees. R. flabellifer sp. n., R. golovatchi sp. n., R. rigonanae sp. n., R. spiridonovi sp. n. et R. voratum sp. n. sont differencies les uns des autres et des autres especes du genre par une combinaison de caracteres incluant la forme de l'extremite cephalique, le developpement et l'etendue de la pilosite, le type de tractus genital femelle, la forme de la queue du male et de la femelle, la forme des spicules et le nombre et la repartition des papilles copulatrices. Deux especes, provenant toutes deux de Diplopodes Polydesmides, portent une projection inhabituelle, pedonculee, en forme de languette, sur chacun des secteurs de l'ouverture buccale triangulaire et comptent seulement treize papilles copulatrices. De telles projections n'ont ete precedemment decrites que chez R.lanceacauda, une espece originaire des Antilles, qui exhibe egalement un cortege reduit de treize papilles chez le male avec la meme repartition. La morphologie, le comportement et la repartition des Rhigonema sont discutes et la preuve est apportee pour la premiere fois que la nematophagie est pratiquee par au moins une espece de ce genre. Rhigonema leonilae (Sanchez-Velazquez, 1979) comb. n. est propose pour Ruizia leonilae Sanchez-Velazquez, 1979.
Abirovulva gen. n. is proposed for nematode denizens of the gut of various African polydesmid diplopods (Coromus thomsoni , Oxydesmus mimodesmus parabellus , O. sicarius , O. platycercus concolor , Plagiodesmus brunneus , P. variabilis and Prepodesmus ornatus). The new genus is usually accompanied by species of Afrocarnoya (also apparently restricted to polydesmid diplopods) and Rhigonema and is likely to be distributed throughout the Central to West African region. Abirovulva gen. n. is unique amongst African Carnoyidae because of a combination of characters, including the very posteriorly located vulva, the unusual form of the female genital system, presence of a ventral sucker in the male, the shape of the spicules and gubernaculum and the distribution of the male copulatory papillae. Abirovulva insolita gen. n., sp. n. is proposed as the type species and is characterised by: the strongly inflated intestine just posterior to the basal bulb in both sexes, the extremely posterior vulva, both female genital tracts running anteriorly in parallel, presence of a much expanded vagina uterina acting as an egg receptacle, long and robust female tail spike; presence of a ventral sucker in the male, form of the male spicules and gubernaculum, disposition of the 15 copulatory papillae, cuticular callosities on the cloacal lips, well developed, smooth, cephalic cap in the male and the truncate male cephalic extremity. No other genus of African Carnoyidae is known to have such a posterior vulva, ventral sucker in the male or spicules and gubernaculum of such unusual form. Relationships to other genera in the Ransomnematoidea and factors that may influence niche partitioning within the host gut are discussed.
Trachyglossus quintus gen. n., sp. n. is described from Charactopygus frequens from Zaire. The new genus is characterised by having a dorsoventrally elongate oral aperture with the dorsal jawplate developed into a tongue-like rasp extending over halfway down the corpus lumen; a hypertrophied corpus and isthmus; well developed, lobate caudal alae in the male; hypertrophied, lobiform, vulval flap and by the form of the spicules and disposition of the copulatory papillae. It is closest to Xustrostoma, a genus with which it shares the development of a tongue-like rasp, but differs principally in the hypertrophy of the pharyngeal components: in Trachyglossus gen. n. it is the corpus and isthmus which are enlarged whereas in Xustrostoma it is the basal bulb. Trachyglossus gen. n. also differs in having strongly developed, lobate, caudal alae in the male (vs absent) and in possessing a lobiform anterior vulval lip. It differs from Obainia in having the dorsal jaw plate modified to form a tongue-like rasp, corpus and isthmus region of pharynx hypertrophied (vs basal bulb in African species of Obainia), hypertrophied vulval flap, form of spicules, distribution of copulatory papillae and presence of caudal alae in the male. From Zalophora it differs in the form of the pharynx, development of a tongue-like dorsal rasp instead of numerous teeth on the dorsal jawplate, presence of a hypertrophied vulval lobe and in being amphimictic instead of parthenogenetic. Xustrostomatidae fam. n. is proposed for all those genera (formerly included in the Rhigonematidae) with the cephalic capsule laterally compressed to form a dorsoventrally orientated oral aperture. Rhigonema multipapillatum (Skrjabin, 1916), previously known only from the original description, is redescribed and established as a valid species on the basis of material from Uganda. A neotype is proposed. The species is characterised by medium body size; posterior margin of cephalic collar fused to body; presence of fine microtrichs in the cervical region; cuticularised mouth plates clothed in minute spine-like structures; Type 1 female genital tract; conoid spicate tail shape in both sexes; form of the long, slender spicules and disposition of the 31 copulatory papillae, three postcloacal pairs of which being subdorsal or sublateral in position.
Three new species of the genus Brumptaemilius Dollfus, 1952 are described from the intestine of diplopods from Ghana and Ivory Coast. Brumptaemilius ultimus sp. n., from Ghana and Ivory Coast, is characterised by the huge spicules (731-894 μm long); numerous (105-136) transverse striae on the spicule shafts; the verrucose appearance of the tuberculate papillae; the blunt, peg-like spines on the posterior cloacal lip; the disposition and form of the rugosities; the very short male tail spike (0.3-0.5 times as long as the gubernaculum); lateral alae absent in both sexes and the exceptionally long female vagina. A spermatophore is apparently absent. B. verrucosus sp. n., from Ivory Coast, is characterised by relatively few tuberculate papillae with a minutely verrucose appearance; relatively long spicules (519-553 μm) with numerous (84-95) transverse striae; spicule shafts parallel and not wrapped around one another distally; gubernaculum 77-87 μm long; presence of subventral paracloacal fields of digitiform rugosities and male tail spike 0.6 (0.6-0.7) times as long as gubernaculum. In addition, the female lateral alae start in the isthmus region and terminate shortly before the anus, and a spermatophore is apparently absent, although a prominent copulatory plug was often seen occluding the vaginal lumen. Brumptaemilius ypoxystus sp. n., from Ivory Coast, is distinguished by features of the male copulatory apparatus and the area rugosa. It is characterised by having four staggered rows of subventral tuberculate papillae, each bearing a terminal corona of ca five to nine minute projections; a postcloacal field comprising transverse, imbricate rows of broad, conical spines; the form and disposition of the subventral fields of rugosities; rugose fields not extending as a ventral band anterior to the cloacal aperture; non-rugose ventral region on tail posterior to last pair of postcloacal papillae; spicules 306 (280-328) μm long with 40 (33-48) transverse striae; gubernaculum 102 (91-107) μm long; tail spike 0.5 (0.4-0.6) times as long as the gubernaculum; lateral alae absent in both sexes and presence of a spermatophore bearing a short peduncle penetrating the distal vagina. A population of B.seychellarum Adamson, 1987 is described from the Seychelles and the presence of a spermatophore recorded in the species for the first time. Useful characters for species diagnosis within the genus are briefly discussed.
Six new species of Rhigonema are described from the gut of various African diplopods. Rhigonema fecundum sp. n., from South Africa, is characterised by medium to fairly long body length, finely pilose anterior region, posterior margin of cephalic collar smoothly fused to body contour, Type 2 genital tract with a long ovejector, presence of a long, closely adpressed, vulval flap, tail shape in both sexes, broad spicules of medium length and complement of 23 copulatory papillae of which three pairs are subdorsal or sublateral in position. Rhigonema oxydesmi sp. n., from Oxydesmus platycercus concolor, Zaire, is characterised by medium body length, slightly projecting cephalic collar, finely pilose anterior region, Type 2 female genital tract with a long ovejector, presence of a short, adpressed, vulval flap, tail shape in both sexes, medium length spicules with a hamate capitulum and complement of 23 copulatory papillae, three pairs of which are subdorsal or sublateral in position. Rhigonema peziphorum sp. n., from Sphaerotherium selindum, Zimbabwe, is characterised by medium body length, prominently projecting cephalic collar, finely pilose anterior region, Type 1 female genital tract with a medium length ovejector, rather large eggs, absence of a prominent vulval flap, presence of a spermatophore, tail shape in both sexes, unusually short spicules with a weakly hamate capitulum and complement of 23 copulatory papillae. It is the only known Rhigonema species to form a spermatophore. Rhigonema rostrellum sp. n., from Ivory Coast, is characterised by medium body length, finely pilose anterior region, Type 2 genital tract with a very long ovejector, presence of a closely adpressed vulval flap, tail shape in both sexes, broad spicules of medium length and complement of 23 copulatory papillae of which three pairs are subdorsal or sublateral in position. Rhigonema spicatum sp. n., from Congoromus flabellatus, Zaire, is characterised by medium body length, slightly projecting cephalic collar, densely pilose anterior region, Type 2 female genital tract with a long ovejector, presence of an adpressed vulval flap, tail shape in both sexes, relatively short spicules with a hamate capitulum and complement of 23 copulatory papillae. Rhigonema xiphiurus sp. n., from Oxydesmus sicarius, Zaire, is characterised by medium body length, projecting cephalic collar, coarsely pilose anterior region with bristly microtrichs, microtrichs extending down body to beyond vulval level in female and a similar relative position in the male, Type 2 female genital tract with a long ovejector, elongate female tail, convex conoid male tail with an exceptionally well developed subulate projection, very short spicules and disposition of the 23 copulatory papillae, three pairs of which are dorsal or sublateral in position. A synopsis of the other eight nominal species of African Rhigonema is appended.