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Zeng Qi Zhao - One of the best experts on this subject based on the ideXlab platform.

  • Halanonchus scintillatulus sp. nov. from New Zealand and a review of the suborder Trefusiina (Nematoda: Enoplida)
    European Journal of Taxonomy, 2020
    Co-Authors: Daniel Leduc, Zeng Qi Zhao, Frederic Sinniger
    Abstract:

    We provide a review of the enoplid suborder Trefusiina Siddiqi, 1983, based on morphological considerations and analyses of new and published 18S rDNA sequences. We also describe Halanonchus scintillatulus Leduc sp. nov. from the Hauraki Gulf, northern New Zealand, as well as females of Trefusialaimus idrisi Leduc, 2013 from the continental slope of New Zealand. We show for the first time that the structure of the female reproductive system of Trefusialaimus Riemann, 1974 consists of two opposed and outstretched ovaries, an unusual feature for the Enoplida. The Trefusiina did not form a monophyletic group in the 18S rDNA phylogeny due to the placement of Lauratonema Gerlach, 1953 and Trefusialaimus sequences well away from the main Trefusiina clade. However, due to generally weak Maximum Likelihood support values, we refrain from changing the classification of these taxa until more comprehensive analyses can be conducted. Our phylogenetic analysis supports the inclusion of the Trischistomatidae Andrassy, 2007 within the Trefusiina, meaning that all of the enoplid suborders now include at least some terrestrial/freshwater representatives. The Trefusiina currently comprises five families, 14 genera and 92 valid species.

  • Phylogenetic position of the enigmatic deep-sea nematode order Rhaptothyreida: A molecular analysis.
    Molecular Phylogenetics and Evolution, 2018
    Co-Authors: Daniel Leduc, Zeng Qi Zhao, Valentin Verdon
    Abstract:

    Abstract The placement of the rare deep-sea nematode order Rhaptothyreida remains unclear due to the unique morphology of this group, an unknown life cycle with morphologically distinct juvenile stages which may or may not be parasitic, and lack of molecular sequences. Here, we investigate the phylogenetic placement and status of the Rhaptothyreida based on SSU and D2-D3 of LSU rDNA sequences of Rhaptothyerus typicus specimens obtained from the continental slope of New Zealand. Molecular sequences of three adults and a late stage juvenile were identical, confirming that they belong to the same species despite pronounced morphological differences. We observed the presence of the rare nucleotide transition A → G and transversion G → Y in the loops of Hairpin 35 and 48 regions, which is consistent with the placement of R. typicus within the order Enoplida. Rhaptothyreus typicus was consistently recovered as a long branch clade in SSU and D2-D3 of LSU analyses, which can have a destabilising effect on tree topology. After Gblocks were used to remove sites of questionable alignment, R. typicus was placed in a clade comprising Trissonchulus, Dolicholaimus and Ironus sequences (family Ironidae, order Enoplida) in both Bayesian and Maximum Likelihood SSU topologies. Depending on which alignment algorithm was used, analyses of LSU sequences focusing on enoplid taxa either suggested a relationship between R. typicus and Halalaimus (family Oxystominidae) or did not identify any clear relationships. Overall, our results provide strong evidence for placing R. typicus and the family Rhaptothyreidae within the order Enoplida, although further work is required to clarify relationships between rhaptothyreids and other enoplid taxa. A parasitic lifestyle could explain the unique morphology of this group, their highly divergent SSU and LSU rDNA molecular sequences, and the marked morphological differences between late juveniles and adults. Further molecular investigations targeting both free-living and parasitic early juvenile life stages in potential deep-sea hosts are needed to better understand the evolution of this unusual nematode taxon.

  • A new species and a new record of Trischistoma Cobb, 1913 (Nematoda: Enoplida: Trischistomatidae) from Shanxi Province, China
    2015
    Co-Authors: Xu, Yu Mei, Zeng Qi Zhao, Wang, Jian Ming
    Abstract:

    Xu, Yu Mei, Zhao, Zeng Qi, Wang, Jian Ming (2015): A new species and a new record of Trischistoma Cobb, 1913 (Nematoda: Enoplida: Trischistomatidae) from Shanxi Province, China. Zootaxa 3937 (3): 564-576, DOI: http://dx.doi.org/10.11646/zootaxa.3937.3.

  • placed in Enoplida
    2013
    Co-Authors: Zeng Qi Zhao, Thomas R. Buckley
    Abstract:

    We have made an extensive study of New Zealand representatives of nematodes from the family Tripylidae de Man, 1876. Based on SSU DNA sequence data and phylogenetic analysis, the genera Tripylina Brzeski, 1964 and Trischistoma Cobb, 1913 are not closely related to Tripyla Bastian, 1865, the type genus of the family Tripylidae de Man 1876. The genus Tripylina is sister to Trischistoma and Trefusia de Man, 1893 and is more closely related to Enoplida than to Triplonchida. Our phylogenetic results indicate that Tripylina should be placed in Enoplida

  • Analysis of primary structure loops from Hairpins 35 and 48 of the Nematoda SSU rRNA gene provides further evidence that the genera Tripylina Brzeski, 1963, Trischistoma Cobb, 1913 and Rhabdolaimus de Man, 1880 are members of Enoplida
    Zootaxa, 2012
    Co-Authors: Zeng Qi Zhao, Thomas R. Buckley
    Abstract:

    A comparison of small subunit (SSU) rDNA sequences has revealed that a rare nucleotide transition A→G and a trans-version G→Y occurred simultaneously in the evolutionarily conserved loops of Hairpins 35 and 48 of the SSU rRNA geneof Tripylina Brzeski 1963, Trischistoma Cobb 1913 and Rhabdolaimus de Man 1880. The same pair of substitutions oc-curred in all Enoplida analysed but not in other nematodes. This evidence from the primary structure of Hairpins 35 and48 indicates that Tripylina, Trischistoma and Rhabdolaimus are members of Enoplida, supporting previous phylogenetic analyses.

Thomas R. Buckley - One of the best experts on this subject based on the ideXlab platform.

Nils Thorstein Hagen - One of the best experts on this subject based on the ideXlab platform.

  • Systematic affinity of the sea urchin parasite, Echinomermella matsi Jones & Hagen (Enoplida: Echinomermellidae)
    Nematology, 2011
    Co-Authors: George Poinar, Samantha C. Lewis, Bradley C. Hyman, Nils Thorstein Hagen
    Abstract:

    Morphological and molecular studies were used to determine the systematic affinity of the sea urchin parasite, Echinomermella matsi. The absence of somatic ornamentation and external openings in the parasitic juveniles and adults, aside from a small non-functional mouth and male reproductive opening, shows a striking degree of morphological reduction in Echinomermella as an adaptation to a parasitic life style. A phylogenetic analysis of E. matsi by the maximum likelihood (ML) and neighbour-joining (NJ) methods places it within the Order Enoplida. This indicates that Echinomermella evolved from free-living marine enoplids and is not closely related to the Mermithidae as previously thought. The absence of a vulva and male genital supplements, coupled with the modified spicule tips, suggest that traumatic insemination is the standard method of mating. The morphological modifications in Echinomermella indicate a long period of co-evolution with sea urchins, possibly extending back to the Palaeozoic.

  • systematic affinity of the sea urchin parasite echinomermella matsi jones hagen Enoplida echinomermellidae
    Nematology, 2011
    Co-Authors: George Poinar, Samantha C. Lewis, Bradley C. Hyman, Nils Thorstein Hagen
    Abstract:

    Morphological and molecular studies were used to determine the systematic affinity of the sea urchin parasite, Echinomermella matsi. The absence of somatic ornamentation and external openings in the parasitic juveniles and adults, aside from a small non-functional mouth and male reproductive opening, shows a striking degree of morphological reduction in Echinomermella as an adaptation to a parasitic life style. A phylogenetic analysis of E. matsi by the maximum likelihood (ML) and neighbour-joining (NJ) methods places it within the Order Enoplida. This indicates that Echinomermella evolved from free-living marine enoplids and is not closely related to the Mermithidae as previously thought. The absence of a vulva and male genital supplements, coupled with the modified spicule tips, suggest that traumatic insemination is the standard method of mating. The morphological modifications in Echinomermella indicate a long period of co-evolution with sea urchins, possibly extending back to the Palaeozoic.

C. Jamard - One of the best experts on this subject based on the ideXlab platform.

  • À propos de deux observations d'helminthoses hépatiques sur des marmottes,
    EDP Sciences, 2014
    Co-Authors: J. Gevrey, F. Beugnet, C. Jamard
    Abstract:

    Deux autopsies de marmottes américaines, Marmota monax, servant de modèle expérimental d'hépatite virale, ont permis l'identification de deux parasites à localisation hépatique, Taenia mustelae (larvae) (Cestoda : Taeniidae), et Calodium hepaticum (Nematoda : Enoplida : Capillariinae). Les auteurs présentent l'identification de ces parasites, basée sur l'observation des cysticerques dans le cas de Taenia mustelae, et sur celle des œufs dans le cas de l'infestation par C. hepaticum. Le problème de l'inter-action possible entre l'infestation parasitaire à localisation hépatique et l'infection virale par le Woodchuck Hepatitis Virus reste posé

  • À propos de deux observations d'helminthoses hépatiques sur des marmottes, Marmota monax, infectées par le virus de l'hépatite virale (WHV)
    Parasite, 1996
    Co-Authors: J. Gevrey, F. Beugnet, C. Jamard
    Abstract:

    Deux autopsies de marmottes americaines, Marmota monax , servant de modele experimental d'hepatite virale, ont permis l'identification de deux parasites a localisation hepatique, Taenia mustelae (larvae) (Cestoda : Taeniidae), et Calodium hepaticum (Nematoda : Enoplida : Capillariinae). Les auteurs presentent l'identification de ces parasites, basee sur l'observation des cysticerques dans le cas de Taenia mustelae , et sur celle des œufs dans le cas de l'infestation par C. hepaticum . Le probleme de l'inter-action possible entre l'infestation parasitaire a localisation hepatique et l'infection virale par le Woodchuck Hepatitis Virus reste pose.

Rafael Morales - One of the best experts on this subject based on the ideXlab platform.

  • The influence of ionic composition on the distribution of nematode species in springs of the province of Granada (Spain)
    Hydrobiologia, 1992
    Co-Authors: Amelia Ocaña, Rafael Morales
    Abstract:

    The ionic composition of 38 mineral springs in the province of Granada (Spain), and the distribution of 45 species of nematodes belonging to orders Monhysterida, Araeolaimida, Chromadorida and Enoplida were examined. Water chemistry is used to make two diagrams representing anionic and cationic composition. Diagrams for anionic composition (given the greater variance seen in the springs considered) are used to illustrate the distribution of individual species. The results obtained from species distribution and the correlation between species made it possible to group species which could be associated with springs where each of the anions considered predominated. A greater number of species groups was found to inhabit springs in which chloride concentrations was less than 50% of the total concentration of anions.