Morphology, genetic characterization and molecular phylogeny of the poorly known nematode parasite Cissophyllus leytensis Tubangui &amp; Villaamil, 1933 (Nematoda: Ascaridida) from the Philippine sailfin lizard Hydrosaurus pustulatus (Eschscholtz, 1829) (Reptilia: Squamata)

Ni, Xue-Feng; Chen, Hui-Xia; Xu, Zhichao; Gu, Xiao-Hong; Li, Liang

doi:10.1186/s13071-022-05224-8

Cited by 6 publications

(5 citation statements)

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“…In Rhigonematomorpha, only 21 nominal species have been genetically characterized [14-17, 19, 20], and most of the data available are represented by the 18S and 28S sequences, which are commonly used for molecular phylogeny of higher taxa within Nematoda [21][22][23][24][25][26]. Although the nuclear internal transcribed spacer (ITS) region and the mitochondrial cox1 and cox2 genes are widely used as powerful and practical genetic markers for revealing sibling or cryptic species, delimiting phenotypic variation and identifying species in the infraorders Ascaridomorpha, Spiruromorpha and Oxyuridomorpha [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44], they have been scarcely employed in studies pertaining to Rhigonematomorpha species. Consequently, no current knowledge on the effectiveness of ITS, cox1 and cox2 as genetic markers for identification of Rhigonematomorpha nematodes is available.…”

Section: Introductionmentioning

confidence: 99%

Molecular identification of a new species of Rhigonema (Nematoda: Rhigonematidae) and phylogenetic relationships within the infraorder Rhigonematomorpha

et al. 2022

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Background The infraorder Rhigonematomorpha comprises a group of obligate parasitic nematodes of millipedes (Arthropoda: Diplopoda). The current species identification of Rhigonematomorpha nematodes remains mainly based on morphological features, with molecular-based identification still in its infancy. Also, current knowledge of the phylogeny of Rhigonematomorpha is far from comprehensive. Methods The morphology of Rhigonematomorpha nematodes belonging to the genus Rhigonema, collected from the millipede Spirobolus bungii Brandt (Diplopoda: Spirobolida) in China, was studied in detail using light and scanning electron microscopy. Five different genetic markers, including the nuclear small ribosomal subunit (18S), internal transcribed spacer (ITS) and large ribosomal subunit (28S) regions and the mitochondrial cox1 and cox2 genes of these Rhigonematomorpha nematodes collected from China and Rhigonema naylae collected from Japan were sequenced and analyzed using Bayesian inference (BI) and Assemble Species by Automatic Partitioning (ASAP) methods. Phylogenetic analyses that included the most comprehensive taxa sampling of Rhigonematomorpha to date were also performed based on the 18S + 28S genes using maximum likelihood (ML) and BI methods. Results The specimens of Rhigonema collected from S. bungii in China were identified as a new species, Rhigonema sinense n. sp. Striking variability in tail morphology was observed among individuals of R. sinense n. sp. ASAP analyses based on the 28S, ITS, cox1 and cox2 sequences supported the species partition of R. sinense n. sp. and R. naylae, but showed no evidence that the different morphotypes of R. sinense n. sp. represent distinct genetic lineages. BI analyses also indicated that R. sinense n. sp. represents a separated species from R. naylae based on the cox1 and cox2 genes, but showed that R. naylae nested in samples of R. sinense n. sp. based on the ITS and 28S data. Phylogenetic results showed that the representatives of Rhigonematomorpha formed two large clades. The monophyly of the families Carnoyidae and Ichthyocephalidae and the genus Rhigonema was rejected. The representatives of the family Ransomnematidae clustered together with the family Hethidae with strong support. Conclusions A new species of Rhigonematomorpha, R. sinense n. sp. is described based on morphological and molecular evidence. ASAP analyses using 28S, ITS, cox1 and cox2 data indicate the striking variability in tail morphology of R. sinense n. sp. as intraspecific variation, and also suggest that partial 28S, ITS, cox1 and cox2 markers are effective for molecular identification of Rhigonematomorpha nematodes. The phylogenetic results support the traditional classification of Rhigonematomorpha into the two superfamilies Rhigonematoidea and Ransomnematoidea, and indicate that the families Carnoyidae and Ichthyocephalidae and the genus Rhigonema are non-monophyletic. The present phylogeny strongly supports resurrection of the family Brumptaemiliidae, and also indicates that the family Ransomnematidae is sister to the family Hethidae. Graphical Abstract

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Section: Introductionmentioning

confidence: 99%

Molecular identification of a new species of Rhigonema (Nematoda: Rhigonematidae) and phylogenetic relationships within the infraorder Rhigonematomorpha

et al. 2022

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“…The monophyly of the Cosmocercidae family has been corroborated by several studies (Tran et al, 2015;Sinsch et al, 2019;Sinsch et al, 2020;Ni et al, 2022); nonetheless, due to the low sampling of taxa, geographic limitations and few molecular data available, the phylogenetic relationships between the genera of the family are still unclear. Sinsch et al (2020) and Chen et al (2020) during phylogenetic studies, using the 18S and internal transcribed spacer 1 ribosomal markers, demonstrated that the genera Cosmocerca and Cosmocercoides are phylogenetically close related.…”

Section: Discussionmentioning

confidence: 93%

“…The monophyly of the Cosmocercidae family has been corroborated by several studies (Tran et al ., 2015 ; Sinsch et al ., 2019 ; Sinsch et al ., 2020 ; Ni et al ., 2022 ); nonetheless, due to the low sampling of taxa, geographic limitations and few molecular data available, the phylogenetic relationships between the genera of the family are still unclear. Sinsch et al .…”

Section: Discussionmentioning

confidence: 99%

“…Our phylogeny showed a clade formed by C. pulcher + C. qingtianensis (with low support). In phylogenetic studies using 18S and 28S from the Oriental region, the authors recovered a clade formed by sequences of the species C. pulcher + C. tonkinensis and C. qingtianensis or C. pulcher and C. tonkinensis (Tran et al ., 2015 ; Chen et al ., 2020 , 2021 ; Harnoster et al ., 2022 ; Ni et al ., 2022 ).…”

Section: Discussionmentioning

confidence: 99%

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Morphological and molecular characterization of Cosmocercoides amapari n. sp. (Nematoda: Cosmocercidae), parasitic in hylid frogs from the Brazilian Amazon

et al. 2023

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Cosmocercoides Wilkie, 1930 are gastrointestinal parasites commonly found in amphibians and reptiles, with 4 species reported from the Neotropical region. In the present study, a new species of Cosmocercoides, namely Cosmocercoides amapari n. sp. is described using integrated approaches such as light and scanning microscopy, and DNA sequencing of the mitochondrial cytochrome c oxidase subunit 1 gene. The specimens were collected from the large intestine of 3 species of hylid frogs in Amapá, Brazil. The new species can be distinguished from its congeners by morphological traits, including the pattern of caudal papillae, absence of the gubernaculum, 2 poorly sclerotized spicules, presence of lateral alae and somatic papillae along the body. In addition, our molecular analyses and phylogenetic reconstructions strongly support the status of the new taxon, which clustered poorly with a large clade of Cosmocerca spp. Cosmocercoides amapari n. sp. is the 29th species of the genus, the 5th from the Neotropical region, the third reported in Brazil, the second described from the Amazon region and the first belonging to the Neotropical region with molecular data.

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“…We performed morphological identification on nematodes obtained from 93 captive and 11 wild PHs. The lactophenol clarification procedure was conducted as previously described [ 26 ]. All strongylids were classified based on the morphological characteristics outlined by Lichtenfels et al [ 8 ] and Zhang and Kong [ 10 ].…”

Section: Methodsmentioning

confidence: 99%

First report of four rare strongylid species infecting endangered Przewalski’s horses (Equus ferus przewalskii) in Xinjiang, China

Jia,

Gao,

Tang

et al. 2023

Parasites Vectors

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Background The Przewalski's horse (Equus ferus przewalskii) is the only surviving wild horse species in the world. A significant population of Przewalski's horses resides in Xinjiang, China. Parasitosis poses a considerable threat to the conservation of this endangered species. Yet, there is limited information on the nematode parasites that infect these species. To deepen our understanding of parasitic fauna affecting wild horses, we identified the intestinal nematodes of Przewalski’s horses in Xinjiang and added new barcode sequences to a public database. Methods Between 2018 and 2021, nematodes were collected from 104 dewormed Przewalski's horses in Xinjiang. Each nematode was morphologically identified to the species level, and selected species underwent DNA extraction. The extracted DNA was used for molecular identification through the internal transcribed spacer 2 (ITS2) genetic marker. Results A total of 3758 strongylids were identified. To the best of our knowledge, this is the first study to identify four specific parasitic nematodes (Oesophagodontus robustus, Bidentostomum ivashkini, Skrjabinodentus caragandicus, Petrovinema skrjabini) and to obtain the ITS2 genetic marker for P. skrjabini. Conclusions The ITS2 genetic marker for P. skrjabini enriches our understanding of the genetic characteristics of this species and expands the body of knowledge on parasitic nematodes. Our findings extend the known host range of four strongylid species, thereby improving our understanding of the relationship between Przewalski’s horses and strongylids. This, in turn, aids in the enhanced conservation of this endangered species. This study introduces new instances of parasitic infections in wild animals and offers the DNA sequence of P. skrjabini as a valuable resource for molecular techniques in nematode diagnosis among wildlife. Graphical Abstract

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Morphology, genetic characterization and molecular phylogeny of the poorly known nematode parasite Cissophyllus leytensis Tubangui & Villaamil, 1933 (Nematoda: Ascaridida) from the Philippine sailfin lizard Hydrosaurus pustulatus (Eschscholtz, 1829) (Reptilia: Squamata)

Cited by 6 publications

References 26 publications

Molecular identification of a new species of Rhigonema (Nematoda: Rhigonematidae) and phylogenetic relationships within the infraorder Rhigonematomorpha

Molecular identification of a new species of Rhigonema (Nematoda: Rhigonematidae) and phylogenetic relationships within the infraorder Rhigonematomorpha

Morphological and molecular characterization of Cosmocercoides amapari n. sp. (Nematoda: Cosmocercidae), parasitic in hylid frogs from the Brazilian Amazon

First report of four rare strongylid species infecting endangered Przewalski’s horses (Equus ferus przewalskii) in Xinjiang, China

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