Reappraisal of the specific status of rhabdias (nematoda: Rhabdiasoidea) from malagasy chameleons in the Paris museum collection

Abstract

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 Calumma cucullatum in the northeastern region (Cap Machoual). In the eastern region, R. nasutum n. sp. is parasitic in C. nasutum, and R. brevicome 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. brevicome 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.