A new species of Rhabdias Stiles et Hassall, 1905 (Nematoda: Rhabdiasidae) from Blommersia domerguei (Guibé) (Amphibia: Mantellidae) in Madagascar

Three new species of Rhabdias Stiles et Hassall, 1905 (Nematoda: Rhabdiasidae) parasitic in Ptychadena spp. (Amphibia: Anura: Ptychadenidae) and an identification key to Rhabdias spp. from Afrotropical anurans

Three new species of lung-dwelling nematodes are described from the frogs Ptychadena anchietae (Bocage), P. oxyrhynchus (Smith), and P. uzungwensis (Loveridge) in southern Africa. All three species are medium-sized species of Rhabdias Stiles et Hassall, 1905, with the thick-walled buccal capsules measuring 11-13 μm × 6-11 μm, consisting of longer anterior and shorter posterior parts. Rhabdias athos n. sp. and R. porthos n. sp. are characterised by the rounded anterior end of the body and the presence of short dilatation of the oesophagus at its mid-length. Rhabdias porthos n. sp. has distinct excretory glands which are absent in two other species. Rhabdias aramis n. sp. is characterised by the truncated anterior end and the slight constriction of the oesophagus at the level of its mid-length. Phylogenetic analysis based on ITS-28S rDNA sequences placed R. aramis n. sp. in the clade consisting of R. engelbrechti Kuzmin et al., 2017 from South Africa and Eurasian Rhabdias spp., while R. athos n. sp. and R. porthos n. sp. formed a sister group to that clade. Identification key to 14 Rhabdias spp. parasitic in anuran amphibians from the Afrotropical Realm is provided.

First record of Metapolystoma (Monogenea: Polystomatidae) from Boophis tree frogs in Madagascar, with the description of five new species

Although Madagascar has more than 350 frog species of which all but two are endemic to the island, the known polystome (Monogenea: Polystomatidae) diversity parasitizing Malagasy frogs is low, encompassing five species of Madapolystoma, one species of Kankana and one Metapolystoma. Investigating the parasite diversity of frog parasites at selected Malagasy localities led to the discovery of undescribed polystomes. Five treefrogs, Boophis albilabris, Boophis doulioti, Boophis luteus, Boophis madagascariensis and Boophis occidentalis were found to be infected and are reported here as hosts for new Metapolystoma species. Morphological investigation, combining examination of body length, haptor length, genital bulb width, genital crown diameter, genital spine number, genital spine length, ovary length, egg length, hamulus length, hamulus guard length and hamulus hook length, revealed five distinct morphotypes. Phylogenetic analysis and genetic divergences obtained for three of the five morphotypes, support the distinction of new species. Metapolystoma ansuanum n. sp. is described from B. luteus, Metapolystoma falcatum n. sp. from B. doulioti, Metapolystoma multiova n. sp. from B. occidentalis, Metapolystoma theroni n. sp. from B. madagascareniensis and Metapolystoma vencesi n. sp. from B. albilabris. Finally, although the validity of Metapolystoma as taxon is not fully resolved yet, the phylogenetic position of the described species and their morphology provide clear evidence for new metapolystome taxa.

Description and molecular characterisation of a new nematode species parasitic in the lungs of Strongylopus grayii (Smith) (Anura: Pyxicephalidae) in South Africa

Rhabdias delangei n. sp. (Nematoda: Rhabdiasidae) is described from the lungs of the clicking stream frog Strongylopus grayii (Smith) in the Western Cape Province of South Africa. The new species is characterised by the nerve-ring being located just posterior to the mid-length of the oesophagus, a pre-equatorial vulva, as well as a thin-walled and apparently underdeveloped rectum. Pairwise analyses based on ITS-28S and partial cox1 gene fragments showed significant differences between R. delangei n. sp. and its congeners from the Afrotropical Realm. Rhabdias delangei n. sp. is the 12th species of Rhabdias Stiles & Hassall, 1905 recorded in Afrotropical amphibians and the second species of the genus found in pyxicephalid hosts. Our phylogenetic analysis based on the ITS-28S region showed that the new species is closely related to the European species R. rubrovenosa (Schneider, 1866). Furthermore, both species are similar with respect to the underdeveloped rectum and pre-equatorial position of vulva.

First record of viviparity in polystomatid flatworms (Monogenea: Polystomatidae) with the description of two new species of Madapolystoma from the Madagascan anuran hosts Blommersia domerguei and Mantella expectata

Two frog species, Blommersia domerguei and Mantella expectata, are reported as hosts for new species of Madapolystoma. Phylogenetic analyses and genetic divergences observed in the genus supported the distinction of two morphotypes infesting selectively each host species and morphological investigation combining marginal hooklet morphometrics, genital spine number and measurements further showed that polystomes from the two host species differed from each other and from all other known polystomes. Madapolystoma magnahami n. sp. and Madapolystoma isaloensis n. sp. are therefore described as two new species. Advanced in utero development was illustrated in both polystome species following the observation of well developed hamuli and two pairs of haptoral suckers in developing embryos. Inside some of these in utero embryos a F2 generation embryo was also observed. This is the first report of true viviparity among polystomatid flatworms.

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Two new species of polystomes (Monogenetic flatworms) from Madagascar.

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First indication of true viviparity among the Polystomatidae.

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Unique life cycle with advanced degree of parental care.

Molecular and morphological characterisation of Rhabdias picardiae Junker, Lhermitte-Vallarino et Bain, 2010 (Nematoda: Rhabdiasidae) from Delaland's River Frog, Amietia delalandii (Duméril et Bibron, 1841) (Amphibia: Pyxicephalidae) in South Africa

Rhabdias picardiae previously known from the Guttural Toad, Sclerophrys gutturalis (Bufonidae) is described from a new host, Delaland's River Frog, Amietia delalandii (Pyxicephalidae). The species identification is confirmed by analysis of the COI gene sequence and morphological comparison with the original description. Morphological details of apical structures in adult parasitic R. picardiae, namely, the shape and position of lips, the number and position of external labial papillae, and the buccal capsule morphology are described using light and scanning electron microscopy. The buccal capsule width and length, the distance from anterior end to nerve ring and excretory pore, and ratios of distance to vulva to body length and body length to width were identified as less variable metrical characters in the studied sample of 30 specimens. Adult specimens demonstrated differences in the position of lips in relation to the oral opening and position of the buccal capsule in relation to the oesophagus depending on the size (age) of worms. The infective larvae of R. picardiae are described for the first time and characterised by two lateral alae consisting of two ridges, triangular pseudolabia with rounded tops, and presence of ornamentation on the rounded tail tip.

Microscopic and molecular characterization of Hepatozoon domerguei (Apicomplexa) and Foleyella furcata (Nematoda) in wild endemic reptiles from Madagascar

Madagascar is one of the world's top twelve "megadiversity" hot spots hosting unique and threatened flora and fauna. Parasites are a major component of biodiversity but remain largely uncharacterized in wildlife. In this study we combine microscopic and molecular assessment of hemoparasites in endemic reptile species from Madagascar. We detected three distinct parasites: the apicomplexans Hepatozoon and Sarcocystis, and filarial nematodes. The prevalence and intensity of these apicomplexans were low overall, while microfilarial infections in chameleons were relatively high. We detected mixed infections of two Hepatozoon haplotypes in Madagascarophis colubrinus, and of Hepatozoon and microfilariae in a Furcifer sp. Phylogenetic analyses of Hepatozoon showed evidence of prey-predator transmission, with identical sequences found in the snakes M. colubrinus and Ithycyphus oursi, and their prey Furcifer sp. Based on previous studies regarding the life cycle of Hepatozoon domerguei Landau, Chabaud, Michel, and Brygoo, 1970 in these hosts and due to their morphological similarity, we propose that this Hepatozoon haplotype is Hepatozoon domerguei. Future studies, including the examination of invertebrate hosts, are needed to verify this preliminary taxonomic identification. A distinct hemogregarine haplotype was found in Oplurus sp., which displayed morphologically different gametocytes, some of which were apparently inside leukocytes. The Sarcocystis identified from Tracheloptychus petersi was identical to that reported in a North African snake, indicating that the same lineage is found in geographically distinct regions. By combining morphological and genetic information, Foleyella furcata (Linstow, 1899) filarial nematodes were identified in several Furcifer chameleons. This study provides insights into the distribution, diversity and host-parasite interactions of hemoparasites in wild reptile populations from Madagascar.