Morphological and molecular characterization of <i>Megalobatrachonema hainanensis</i> sp. nov. (Nematoda: Ascaridida), with phylogenetic position of <i>Megalobatrachonema</i> in Cosmocercoidea

Chen, H.-X.; Zhang, L.-P.; Li, L.

doi:10.1017/s0022149x18001086

Cited by 7 publications

(7 citation statements)

References 18 publications

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“…The partial cox1 region was amplified by PCR using the forward primer COIF (5′-TTT TTT GGT CAT CCT GAG GTT TAT -3′) and the reverse primer COIR (5′-ACA TAA TGA AAA TGA CTA ACAAC-3′) [15]. The cycling conditions were described by the previous study [9]. PCR products were checked on GoldView-stained 1.5% agarose gels and purified with the Column PCR Product Purification Kit (Shanghai Sangon, China).…”

Section: Molecular Proceduresmentioning

confidence: 99%

“…The present knowledge of the molecular phylogeny of Cosmocercoidea/Cosmocercidae is still very limited. To date, several studies [8][9][10][11] have provided molecular phylogenetic analyses to solve the systematic status of some genera in Cosmocercoidea using different genetic data. However, due to the paucity and inaccessibility of suitable material of Cosmocercoidea/Cosmocercidae for genetic analysis, all of these molecular phylogenetic studies have included only small numbers of representatives of these taxa.…”

Section: Introductionmentioning

confidence: 99%

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Description of a new species of Aplectana (Nematoda: Ascaridomorpha: Cosmocercidae) using an integrative approach and preliminary phylogenetic study of Cosmocercidae and related taxa

Chen

et al. 2021

Parasites Vectors

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Background Nematodes of the family Cosmocercidae (Ascaridomorpha: Cosmocercoidea) are mainly parasitic in the digestive tract of various amphibians and reptiles worldwide. However, our knowledge of the molecular phylogeny of the Cosmocercidae is still far from comprehensive. The phylogenetic relationships between Cosmocercidae and the other two families, Atractidae and Kathlaniidae, in the superfamily Cosmocercoidea are still under debate. Moreover, the systematic position of some genera within Cosmocercidae remains unclear. Methods Nematodes collected from Polypedates megacephalus (Hallowell) (Anura: Rhacophoridae) were identified using morphological (light and scanning electron microscopy) and molecular methods [sequencing the small ribosomal DNA (18S), internal transcribed spacer 1 (ITS-1), large ribosomal DNA (28S) and mitochondrial cytochrome c oxidase subunit 1 (cox1) target regions]. Phylogenetic analyses of cosmocercoid nematodes using 18S + 28S sequence data were performed to clarify the phylogenetic relationships of the Cosmocercidae, Atractidae and Kathlaniidae in the Cosmocercoidea and the systematic position of the genus Aplectana in Cosmocercidae. Results Morphological and genetic evidence supported the hypothesis that the nematode specimens collected from P. megacephalus represent a new species of Aplectana (Cosmocercoidea: Cosmocercidae). Our phylogenetic results revealed that the Cosmocercidae is a monophyletic group, but not the basal group in Cosmocercoidea as in the traditional classification. The Kathlaniidae is a paraphyletic group because the subfamily Cruziinae within Kathlaniidae (including only the genus Cruzia) formed a seperate lineage. Phylogenetic analyses also showed that the genus Aplectana has a closer relationship to the genus Cosmocerca in Cosmocercidae. Conclusions Our phylogenetic results suggested that the subfamily Cruziinae should be moved from the hitherto-defined family Kathlaniidae and elevated as a separate family, and the genus Cosmocerca is closely related to the genus Aplectana in the family Cosmocercidae. The present study provided a basic molecular phylogenetic framework for the superfamily Cosmocercoidea based on 18S + 28S sequence data for the first time to our knowledge. Moreover, a new species, A. xishuangbannaensis n. sp., was described using integrative approach. Graphical abstract

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Section: Molecular Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Description of a new species of Aplectana (Nematoda: Ascaridomorpha: Cosmocercidae) using an integrative approach and preliminary phylogenetic study of Cosmocercidae and related taxa

Chen

et al. 2021

Parasites Vectors

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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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“…The partial cox1 region was ampli ed by PCR using the forward primer COIF (5′-TTTTTTGGTCATCCTGAGGTTTAT-3′) and the reverse primer COIR (5′-ACATAATGAAAATGACTAACAAC-3′) [15]. The cycling conditions were as described previously [9]. PCR products were checked on GoldView-stained 1.5% agarose gels and puri ed with Column PCR Product Puri cation Kit (Shanghai Sangon, China).…”

Section: Molecular Proceduresmentioning

confidence: 99%

“…Our present knowledge of the molecular phylogeny of the Cosmocercoidea/ Cosmocercidae is still very limited. To date, several studies [8][9][10][11] provided molecular phylogenetic analyses to solve the systematic status of some genera using different genetic data. However, due to the paucity and inaccessibility of suitable material of Cosmocercoidea / Cosmocercidae for genetic analysis, all of these molecular phylogenetic studies have included only small numbers of representatives of the Cosmocercoidea / Cosmocercidae.…”

Section: Introductionmentioning

confidence: 99%

Molecular phylogeny of the family Cosmocercidae (Nematoda: Ascaridida), with description of a new species of Aplectana using an integrative approach

Chen¹,

Gu²,

Ni³

et al. 2021

Preprint

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Background Nematodes of the family Cosmocercidae (Ascaridida: Cosmocercoidea) are mainly parasitic in the digest tract of various amphibians and reptiles worldwide. However, our knowledge of the molecular phylogeny of the Cosmocercidae is still far from comprehensive. The phylogenetic relationships of the Cosmocercidae and the other two families Atractidae and Kathlaniidae in the superfamily Cosmocercoidea, are still under debate. Moreover, the systematic position of some genera in Cosmocercidae remains unclear. Methods Nematodes collected from Polypedates megacephalus (Hallowell) (Anura: Rhacophoridae) were identified using morphological methods (light and scanning electron microscopy) and molecular approaches [sequencing and analyzing the small ribosomal DNA (18S), internal transcribed spacer 1 (ITS-1), large ribosomal DNA (28S) and mitochondrial cytochrome c oxidase subunit 1 (cox1) target regions]. Phylogenetic analyses of cosmocercoid nematodes using 18S + 28S sequence data were performed to clarify the phylogenetic relationships of the Cosmocercidae, Atractidae and Kathlaniidae in the Cosmocercoidea, and the systematic position of the genus Aplectana in Cosmocercidae. Results Morphological and genetic evidence supported that the nematode specimens collected from P. megacephalus represents a new species of Aplectana (Cosmocercoidea: Cosmocercidae). Our phylogenetic results revealed that the Cosmocercidae is a monophyletic group, but not the basal group in Cosmocercoidea as the traditional classification. The Kathlaniidae is a paraphyletic group, and the subfamily Cruziinae (including only the genus Cruzia) formed a sister relationship to the Cosmocercidae. Phylogenetic analyses also showed that the genus Aplectana has closer relationship to the genus Cosmocerca in the Cosmocercidae. Conclusions Our molecular phylogenetic results supported that the subfamily Cruziinae should be moved out from the hitherto-defined family Kathlaniidae and elevated to a separate family, and the genus Cosmocerca has closer relationship to the genus Aplectana in the family Cosmocercidae, Our present study provided the basic molecular phylogenetic framework for the superfamily Cosmocercoidea based on 18S + 28S sequence data for the first time. Moreover, a new species of Aplectana, A. xishuangbannaensis n. sp., was described using an integrative approach.

show abstract

Morphological and molecular characterization of Megalobatrachonema hainanensis sp. nov. (Nematoda: Ascaridida), with phylogenetic position of Megalobatrachonema in Cosmocercoidea

Cited by 7 publications

References 18 publications

Description of a new species of Aplectana (Nematoda: Ascaridomorpha: Cosmocercidae) using an integrative approach and preliminary phylogenetic study of Cosmocercidae and related taxa

Description of a new species of Aplectana (Nematoda: Ascaridomorpha: Cosmocercidae) using an integrative approach and preliminary phylogenetic study of Cosmocercidae and related taxa

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

Molecular phylogeny of the family Cosmocercidae (Nematoda: Ascaridida), with description of a new species of Aplectana using an integrative approach

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