Dataset Information

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.

ABSTRACT: 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.

SUBMITTER: Landman W

PROVIDER: S-EPMC6154473 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature

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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.

Landman Willem W Verneau Olivier O Du Preez Louis L

International journal for parasitology. Parasites and wildlife 20180911 3

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 ...[more]

PMID: 30258781

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Project description:PurposeDespite Madagascar's high amphibian diversity of more than 400 species, only a few polystome species are known from the island. The dissection of frogs from museum collections, together with amphibian and parasite surveys conducted in Madagascar led to the discovery of an undescribed polystome infecting Aglyptodactylus madagascariensis. The purpose of this study is to formally describe this species.MethodsPolystomes recovered from A. madagascariensis were stained (Acetocarmine) and mounted (Canada balsam) to facilitate morphometrics and taxonomic drawings. Some specimens were fixed in absolute alcohol, a Bayesian tree inferred from the analysis of concatenated 18S, 28S and COI gene sequences was constructed and pairwise distances were calculated. Parasites collected from archived hosts in museums were used for histology and scanning electron microscopy (SEM).ResultsPolystomes recovered from A. madagascariensis display characteristics of the genus Metapolystoma and morphologically differed from all other known metapolystomes. The Bayesian phylogeny shows that Metapolystoma n. sp. ex. A. madagascariensis and M. falcatum are sister species with high Bayesian posterior probability. Histological and SEM investigations contributed to morphological descriptions.ConclusionsMorphological examination supported by phylogenetic analysis and genetic divergences revealed distinct differences from all known metapolystome species, supporting the description of a new species. Differences between the life cycles of Metapolystoma and Polystoma provided additional evidence for the validity of that genus as taxon. Whereas Polystoma may display ovoviviparity on rare occasions after incomplete egg expulsion towards the end of the breeding season, Metapolystoma displays true ovoviviparity. We emphasize the need for parasite surveys in Madagascar and recommended for museum material to be examined for polystomes to provide supplementary material and localities for further field investigation.

Project description:BackgroundPolystomatid flatworms in chelonians are divided into three genera, i.e. Polystomoides Ward, 1917, Polystomoidella Price, 1939 and Neopolystoma Price, 1939, according to the number of haptoral hooks. Among the about 55 polystome species that are known to date from the 327 modern living chelonians, only four species of Polystomoides are currently recognised within the 45 South American freshwater turtles.MethodsDuring 2012, several sites in the vicinity of the cities Cayenne and Kaw in French Guiana were investigated for freshwater turtles. Turtles were collected at six sites and the presence of polystomatid flatworms was assessed from the presence of polystome eggs released by infected specimens.ResultsAmong the three turtle species that were collected, no polystomes were found in the gibba turtle Mesoclemmys gibba (Schweigger, 1812). The spot-legged turtle Rhinoclemmys punctularia (Daudin, 1801) was infected with two species of Neopolystoma Price, 1939, one in the conjunctival sacs and the other in the urinary bladder, while the scorpion mud turtle Kinosternon scorpioides (Linnaeus, 1766) was found to be infected with a single Neopolystoma species in the conjunctival sacs. These parasites could be distinguished from known species of Neopolystoma by a combination of morphological characteristics including body size, number and length of genital spines, shape and size of the testis. They were also differentiated at the molecular level using the cox1 gene marker. Based on morphological and genetic evidences, three new species are described herein, namely Neopolystoma cayensis n. sp. and Neopolystoma guianensis n. sp. from the bladder and the conjunctival sacs of R. punctularia, respectively, and Neopolystoma scorpioides n. sp. from the conjunctival sacs of K. scorpioides. However the monophyly of Polystomoides and Neopolystoma is still questioned regarding their phylogeny based on a dataset comprising four concatenated genes, namely, 18S, 28S and 12S rRNA genes and cox1.ConclusionsIn addition to these being the first chelonian polystomes to be reported and described from French Guiana, they represent the first polystomes from the hosts K. scorpioides and R. punctularia and the first representatives of Neopolystoma from South America. Chelonian polystomes now require an in-depth morphological study to reconcile the taxonomy of the genera with species evolution.

Project description:BackgroundThe development of larger monogeneans and their survival on more active hosts is thought to have led to the emergence of haptoral suckers and, in some instances, anchors, enabling a more stable anchorage. Because of their strict host specificity, the morphological variation of anchors in genus Diplorchis (Monogenea: Polystomatidae) may be determined to a large degree by adaptation to the host species, its habitat and ecological environment to ensure stable attachment.MethodsIn this study, we estimated the interspecific and intraspecific differences of haptoral anchors and other morphological characteristics in six recorded species of Diplorchis and one unidentified species parasitizing Sylvirana maosonensis (Bourret, 1937) in China using geometric morphometrics.ResultsGeomorphometric analyses revealed significant differences in the shape and size of the anchors among the seven species, indicating that the morphological differences in anchors can be used as a basis for species identification within the genus Diplorchis. In addition, we found that the same Diplorchis species collected from different localities not only differed significantly in anchor form, but also in body size and haptor size, as well as haptoral sucker size. This may reflect the effect of different habitat environments on biological/behavioral activities of the same host, thus further affecting the stable attachment of flatworms within species. Interestingly, in two species collected from the same localities, we found no significant differences in anchor or sucker size, while body size and haptor size all differed significantly. Meanwhile, the significant differences in anchor shape may suggest that the attachment mechanism of the different Diplorchis species is related to the variation in anchor shape.ConclusionsFrom the perspective of morphological adaptation to the environment, the study not only indicated that the morphological variation of Diplorchis anchors can be used as an auxiliary tool to distinguish species, but also found that the morphological differences in the anchors were influenced by factors such as host species, habitat and ecological environment. This may provide a basis for a better understanding of host-parasite interaction.

Dataset Information

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.

Publications

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

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