Rhabdias (Nematoda: Rhabdiasidae) from Chamaeleonidae (Sauria): two new species from Trioceros ellioti in East Africa and one from Brookesia superciliaris in Madagascar.

Rhabdias casiraghii n. sp. and R. kibiraensis n. sp. are described from Trioceros ellioti from Burundi and co-infection was observed in one of the host specimens. Distinctive characters between these species are, among others, the mouth and buccal capsule in front view, both of which are round in the former and laterally flattened in the latter species. Both species have a complete set of submedian head papillae (three in each submedian axis) as observed in the fourth stage larva of R. americanus from anurans. This primitive character opposes them to other species parasitic in Chamaeleonidae that have a single papilla per axis. The third species is the first described from the primitive chamaeleonid genus Brookesia; R. brygooi n. sp. from B. superciliaris from Madagascar can be distinguished from other Rhabdias in Chamaeleonidae by the small diameter of its mouth and buccal capsule. In this character, it resembles parasites from anurans. However, its infective larva has a rounded caudal extremity ornated with buds, as described in species of Rhabdias parasitic in Chamaeleonidae.

Reappraisal of the specific status of Rhabdias (Nematoda: Rhabdiasoidea) from Malagasy chameleons in the Paris museum collection.

To date Rhabdias gemellipara is the only species described from Malagasy chameleons, but heterogeneity of the material had been suspected. 11 samples of Rhabdias parasites present in the Paris Natural History Museum collection were examined. The size and shape of the buccal capsule, shape and length of the oesophagus, shape of the apical region of the intestine, extent of the genital tract and structure of the cuticular vesicle led to the distinction of five species. Rhabdias rabetafikae n. sp. parasitises Columma cucullatum in the northeastern region (Cap Machoual). In the eastern region, R. nasutum n. sp. is parasitic in C. nasutum, and R. brevicorne n. sp. in C. brevicorne. All three species are similar in size to the African species parasitic in chameleons from which they can be distinguished by several characters. The small species, R. gemellipara, type host C. parsonii from the eastern region, was also found in C. brevicorne from the same geographic region. In the central region, Rhabdias sp., equally collected from C. brevicorne, is distinguished from R. gemellipara by a laterally flattened buccal capsule. All Malagasy species are hermaphrodites. Throughout the worm's life spermatozoids are formed intermittently in a band of cells situated at 1-2 mm from the extremity of the ovaries; they migrate in the ovaries and accumulate in the oviducts.

First report of Rhabdias (Nematoda: Rhabdiasoidea) from lungs of montane chameleons in Cameroon: description of two new species and notes on biology.

The lung nematodes of the genus Rhabdias parasitic in chameleons were previously only known from east Africa and Madagascar. Two new species are described from Cameroon: i) Rhabdias okuensis n. sp., type-host Chamaeleo (Trioceros) quadricomis gracilior, from Mont Oku, is frequent; it resembles R. jarki from Burundi, with a short buccal capsule and a long, thin oesophagus, and is distinguished by its large cervical vesicle and cephalic characters (mouth aperture, papillae). The female parasites are hermaphroditic (spermatozoa identified) and they pierce the lung wall and induce lesions, as R. jarki. In the same locality, another chameleon, C. (T.) w. wiedersheimi also harbours R. okuensis, as demonstrated with the 12S rDNA and coxl gene sequences. ii) R. cristati n. sp., type-host C. (T.) cristatus, from Mount Cameroon, is described from one heavily infected specimen; it resembles R. chamaeleonis from East Africa, and is distinguished by the large buccal capsule and the thick apex of the intestine. The free-living phase, studied in R. okuensis, presents characters of other Rhabdias from chameleons: heterogony, development of larvae through matricidal endotoky, infective larval stages with a thick, rounded caudal extremity, exuvium transformed into a thick cuticular sheeth. Each free-living female produces one larva, as in other African Rhabdias, whereas the female of R. gemellipara, a parasite of a Malagasy chameleon, produces two larvae.

A new rhabdiasid nematode, Chabirenia cayennensis n. g., n. sp., parasitic in the glands of the buccal mucosa of a South American saurian.

Chabirenia cayennensis n. g., n. sp. (Nematoda: Rhabdiasidae) is described from the teiid lizard Ameiva ameiva. A total of 139 worms were recovered, all females, from the mucous glands of the buccal cavity. The worm has a free-living phase in a homogonic life-cycle. Infective larvae are enclosed in a sheath with chequered ornamentation and composed of two exuviae. The new genus is distinct from the five known genera of the family, Pneumonema Johnston, 1916, Acanthorhabdias Pereira, 1927, Entomelas Travassos, 1930, Rhabdias Stiles and Hassall, 1905 and Neoentomelas Hasagawa, 1989, in the following characters: helical habitus, longitudinal cuticular crests, very tiny buccal cavity without thick walls and three oesophageal onchia. Several characters of this new rhabdiasid suggest the Strongylida.

Morphological and biological study of Rhabdias spp. (Nematoda) from African chameleons with description of a new species.

Lung-dwelling females of Rhabdias (Rhabdiasidae), and possible migrating ceolomic young females were searched for in 46 chameleons, belonging to seven species. Rhabdias chamaeleonis, the single species identified to date in Africa, was found in Chamaeleo (Trioceros) johnstoni and C. (T.) hoehnelii, and redescribed; the sizes of the buccal capsule and oesophagus were stable compared to the length of the female parasiles, which varied from 6 mm to 22 mm in length. A second species, R. jarki n. sp., was identified from one C. (T.) johnstoni; it differed from R. chamaeleonis in the shape of anterior region, the longer and slender oesophagus (ratio bulb diameter-body diameter at that level about 1/5 instead of 1/2), the arrangement of the head papillae, the shape of the buccal capsule, and the anatomy of the genital apparatus: one of the ovaries (the anterior or posterior one according to the specimen) had a band of small cells, among larger ovocytes of the synapsis zone, which were likely to generate the spermatozoa present in the oviducts, whereas these two elements were absent from R. chamaeleonis. The parasitic females of R. jarki thus appeared to be hermaphroditic, whereas those of R. chamaeleonis appeared to be parthenogenetic. The free living phase of these Rhabdias species was heterogonic. The infective larva of R. chamaeleonis was 360-590 microns long, unmolile and at third stage inside the maternal cuticle. The free-living male of R. jarki was described. The numerous infective larvae recovered from cultures of unidentified Rhabdias were all in maternal cuticle (one larva/female instead of two as in R. gemellipara from Calumma parsonii, from Madagascar) and two kinds of larvae were identified, R. chamaeleonis and larvae 700-900 microns long provisionally identified to R. jarki. The behaviour of infective larvae and a few successful infections of insects suggest that, in the field, insect transport hosts are involved in transmission and in preventing infective larvae from drying out.