Nematode Specimens Research Articles

Recent deep-sea nematodes and agglutinated foraminifera select specific grains and bioclasts from their environments: Ecological implications

The high-latitude regions are known for a diverse array of benthic meiofauna, yet our understanding of these communities remains limited, particularly in the deep ocean. This study aims to assess the variability and adaptation of nematodes and agglutinated foraminifera in the modern sediments of the Southern Pacific Ocean at >3500 m water depth. Seawater and sediment slurry from the first piston cores (i.e., mudline samples) from International Ocean Discovery Program Sites U1539, U1540, U1541, and U1543 were analyzed for Rose Bengal stained nematode and agglutinated benthic foraminifera. During the microscopic study seven nematode specimens belonging to the genus Desmoscolex, with 16–17, 36 or 38 main rings were found. Scanning electron microscopy study suggest that one morphotype with 17 main rings used only coccoliths of the species Calcidiscus leptoporus while the other specimens used fine-grained siliciclastic material on their concretion ring. Besides nematodes, a few benthic agglutinated foraminifera specimens exclusively used a single species of planktic foraminifera (Globoconella inflata) and/or robust coccoliths, in addition to other fine-grained siliciclastic material, for their test construction. These patterns appear to be highly selective. Specimens of the same benthic nematode Desmoscolex genus and agglutinated foraminifera that have diverse grain types show that these specimens can adapt to their environments, choose specific grains as per their preference, and have no relationship with the grain/particle abundance. This study of Desmoscolex and agglutinated foraminifera species suggests low to moderate organic matter flux and increased ventilation in the abyssal depth of the Southern Pacific Ocean.

Survey the Occurrence of Globocephalus urosubulatus (Nematoda: Ancylostomatidae) in Wild Boars (Sus scrofa) in the State of São Paulo, Brazil.

Although previous studies have characterized the helminth fauna of wild boars kept in captivity in Brazil, records on these helminths in free-ranging animals are still scarce. In view of this, we aimed in our work to investigate the occurrence and morphological and morphometric characteristics of gastrointestinal helminths in wild Sus scrofa from the northwest region of the State of São Paulo, Brazil. The digestive systems of 10 animals (5 males and 5 females of different ages) were used in this study. Each anatomical segment was washed and sieved under running water, and the helminths were separated and identified using light and scanning electron microscopy, according to their morphological characteristics. A total of 2750 (1152 males and 1598 females) nematode specimens were collected from the small intestine of these wild boars, and all of them presented the morphological characteristics of Globocephalus urosubulatus. However, one characteristic is of particular interest because it has not yet been reported in the literature: a marked asymmetry between the lobes and their respective rays of the copulatory bursa, with the left one being larger than the right one. In this research, we identified the presence of G. urosubulatus in all the examined free-ranging wild boars and reported for the first time in the literature the asymmetry in the copulatory bursa.

Simple, inexpensive, and rapid approach to detect changes in the structure of soil free-living nematodes.

A general limitation of ecological investigations based on nematodes is related to the difficult and time-consuming taxonomic identification of species. Therefore, nematologists are investing many efforts to develop alternative approaches as proxies applicable in biomonitoring assessment. Recently, an alternative method that combines morpho-functional traits was proposed for detecting assemblage changes of marine nematodes. In view of the promising results, it was tested the same approach to document taxonomic structure changes of soil free-living and plant parasitic nematodes. Specifically, this attempt was carried out using three data sets that include studies from various European regions and different types of ecosystems: forests, grasslands and maize crops. Multivariate statistical analysis revealed that the simple combination of the four traits (i.e., buccal cavity cuticularization occurrence, amphideal fovea size and shape, morphology of the cuticle and pharynx) in a single code number perfectly mirrors the taxonomic structure trends of the nematode assemblage at genus level. Therefore, we predict that similar results can be also obtained by directly encoding nematode specimens with the selected traits and we point to new important advances if this procedure can be coupled with advanced machine learning.

Sampling and Extraction of Plant Parasitic Nematodes.

The study of nematodes requires availability of nematode specimens and their population densities in plants and soil. This can be achieved using adequate sampling schemes and extraction methods. In this chapter, the most common and suitable sampling and extraction procedures and equipment are described. These include the use of Baermann's funnels, Cobb's decanting and sieving, floating methods such as the Oostenbrink method and Fenwick can, elutriators such as Seinhorst methods, centrifugation methods including that of Coolen, and mechanical and enzymatic maceration. The combination of different methods for cleaning the nematode suspensions is described, such as Cobb's sieving with Baermann's funnels or centrifugation, and for cysts combining Seinhorst's elutriator or Fenwick can with the alcohol methods. Methods for extraction of eggs and/or juveniles of cyst and egg mass forming nematodes, to be used as inoculum or to ascertain egg viability, are also described. Only little information is also noted on the use of molecular tools to identify and quantify nematode populations in soil and roots.

Method for taking Scanning Electron Microscope photographs of nematodes and meiofauna with the support of a low-cost and easy-made container.

This paper presents a method for capturing Scanning Electron Microscope (SEM) photographs of small specimens, including nematodes, arthropods, small insects, and other meiofauna. Our method is tailored to handle nematode specimens mounted on permanent slides, an area with relatively limited documentation. Besides, the process of transferring such delicate specimens from one solution to another has historically posed numerous challenges. To address this issue, we introduce a low-cost and easy-made container designed specifically to facilitate the aforementioned procedure, with a particular focus on SEM photography. The newly introduced container offers a practical solution that enhances the efficiency and effectiveness of specimen handling, ultimately enabling high-quality SEM imaging. This method holds significant promise for researchers working in the field of micro-scopic organism analysis, providing a valuable tool for their investigations with minimum cost.

Body-weight gains in Blaberus craniifer cockroaches and the intensity of their infection with gregarines and nematodes

Intestinal parasites are considered to be able to hinder growth of the host animals, reducing the extent of food metabolism, damaging the intestines’ integrity by filling it with products of their metabolism. However, a long co-evolution can mitigate the negative impact of a parasite on the host organism. To study how parasites – nematodes Cranifera cranifera (Chitwood, 1932) Kloss, 1960 (Oxyurida, Thelastomatidae) and gregarines Protomagalhaensia granulosae Peregrine, 1970 and Blabericola cubensis (Peregrine, 1970) Clopton, 2009 (Eugregarinorida, Blabericolidae) – afffect the growth rates of cockroaches, we performed an experiment on 200 larvae of Blaberus craniifer Burmeister, 1838 (Blattodea, Blaberidae), varying in weight and age. We monitored changes in their body weight, intensity of food consumption, and after the experiment we counted gregarines in the midgut and nematodes in the hindgut. As a result, we found that 100% of the cockroaches were infected with two species of gregarines and one species of nematodes. The intestines of small cockroach larvae (weighing 300–400 mg) contained 16–18 specimens of gregarines on average. Large larvae had a weak tendency towards increase in the intensity of gregarine infestation. Similarly, there occurred changes in the intensity of nematode invasion: young larvae were infected on average by 8–10 specimens of nematodes and large larvae had an average of 12–14 nematodes. At the level of tendency, nematodes were observed to enhance the cockroaches’ growth rates following increase in intensity of the parasitic infection. We found that the two groups of parasites had no effect on one another: the number of gregarines had no effect on the number of specimens of nematodes and vice-versa, the number of nematodes had no effect on the number of gregarine specimens. Perhaps, this is related to different localizations of the parasites: gregarines for most of their life feed in the small intestine, while nematodes feed in the large intestine. Therefore, growth rates of the cockroaches in our experiment have not changed due to the parasites. This indicates minimization of negative effects of gregarines in the midgut and nematodes in the hindgut on the host’s life cycle, developed over long co-evolution.

Helminth Fauna of Juvenile Green Sea Turtles (Chelonia mydas) from Rio de Janeiro State, Brazil.

The helminth fauna of juvenile green sea turtles (Chelonia mydas Linnaeus, 1758) is still poorly known. Herein, we study the gastrointestinal helminths of 28 juvenile green sea turtles found stranded on the north coast of Rio de Janeiro state, Brazil. All turtles were infected showing a rich helminth fauna. In total, 14802 trematodes belonging to 30 species and 5 families including Micros-caphidiidae, Plagiorchiidae, Pronocephalidae, Hapalotrematidae, and Telorchiidae were recovered. An unidentified nematode specimens was also found. The mean intensity was 536 (95% CI = 362 - 853) (range: 1 - 2831), and the species richness was 7.86 (95% CI = 6.46 - 9.21) (range: 1 - 17). The coast of Rio de Janeiro state represents new locality records for Angiodictyum posterovitellatum, Microscaphidium aberrans, M. warui, Octangium hyphalum, O. sagitta, Enodiotrema reductum and Pleurogonius laterouterus. This study confirms that the green sea turtle harbors the richest helminth fauna among sea turtle species and provides useful information on the gastrointestinal helminths of a poorly known stage in the life cycle of this endangered chelonian.

Development and Validation of a High-Throughput Sequencing Test for Mitogenome and rDNA Assembly and Annotation, and Its Use in Support of Nematode Identification of Regulatory Concern

Nematoda is a diverse phylum, and representatives are found in most habitats, including in and on animals and plants. Nematodes are regarded as the most abundant group in terms of individuals in marine and terrestrial sediments. Plant-parasitic nematodes are globally responsible for an annual yield loss of $125 billion. Reliable species identification is essential to take appropriate phytosanitary measures. The introduction of validated Sanger sequencing of 18S, 28S, and cox1 barcode loci represented a powerful tool in support of nematode identification. However, technical challenges associated with PCR and Sanger sequencing and the need for additional loci for identification hamper the efficient use of sequence data. To overcome these challenges, we developed an automated bioinformatic pipeline for the assembly and annotation of mitochondrial genomes and ribosomal DNAs, and we defined and validated a standardized test protocol including controls for routine diagnostics (i.e., high-throughput sequencing [HTS] test). The HTS test can be performed on single nematode specimens and outperforms the Sanger-based sequencing by producing less ambiguous consensus sequences and by yielding additional sequence data offering additional diagnostic resolution when needed. Compared with Sanger sequencing, the HTS test represents a reduction in hands-on time. The HTS test is regarded as fit for the purpose of the molecular identification of single nematode specimens in support of nematode diagnostics of regulatory concern. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .

Equine Strongylidae and other parasitic nematodes described by Arthur Looss during 1895–1911 in the collections of the Swedish Museum of Natural History

Prof. Arthur Looss (1861-1923) was a prolific German parasitologist, who, among other things, authored descriptions of 22 new species of nematodes and 115 new species of trematodes. After his death, his collection (including type material) was split between several institutions: Smithsonian National Museum of Natural History in Washington (USA), Natural History Museum in Berlin and the Natural History Museum in Leipzig (Germany), Gothenburg Museum of Natural History and Swedish Museum of Natural History (Sweden). Here we revise all type specimens of nematodes from the A. Looss collection that are currently preserved in the Swedish Museum of Natural History (Strongylus subtilis, Sclerostomum edentatum, S. vulgare, Cyathostomum labratum, C. coronatum, C. bicoronatum, C. calicatum, C. alveatum, C. catinatum, C. nassatum, C. radiatum, C. elongatum, C. auriculatum, Triodontus minor, T. serratus, C. labiatum and Uncinaria polaris), designate and describe lectotypes wherever deemed necessary and provide catalogue access numbers to all type materials. We also revise all notes and drawings associated with new species that A. Looss described and provide previously unpublished pencilled sketches and ink print-ready drawings of some of these species (Strongylus subtilis, Cyathostomum poculatum, C. radiatum, C. elongatum, C. calicatum, C. auriculatum, Triodontus serratus, Trichostrongylus vitrinus and possibly Necator africanus).

Phylogenetic Analysis of Two Species of Procamallanus (Spirocamallanus) (Nematoda: Camallanidae) Parasitizing Indian Freshwater Fishes

Two species of previously known nematodes from the family Camallanidae were found in different fish hosts in India: the Gangetic mystus Mystus cavasius, the Butter catfish Ompok bimaculatus, and the Zig-zag eel Mastacembelus armatus. The material collected during the study was from two different locations of district Poonch, Jammu and Kashmir, and district Muzaffarnagar district of Uttar Pradesh, India. For molecular analyses, the genomic DNA was extracted, and the 18S ribosomal RNA gene was amplified and sequenced. Specimens of nematodes from the genus Procamallanus clearly resembled all previously known species based on morphology and were identified as Procamallanus (Spirocamallanus) mysti Karve, 1952, and Procamallanus (Spirocamallanus) bilaspurensis Gupta et Duggal, 1973. Molecular data of both species are provided for the first time in India, and a phylogenetic analysis based on 18S rRNA is presented. Molecular data depicted that P. (S.) mysti and P. (S.) bilaspurensis clustered with each other and formed a separate lineage in the phylogenetic tree with 97% ML and 1.00 BI posterior probability values showing homogeneity in sequences, respectively. This study expands the genetic information for Procamallanus species in addition to morphology and, contributing to the limited knowledge of Indian camallanid species.

Acanthopharynx Marine Nematodes (Nematoda, Chromadoria, Desmodoridae) Dwelling in Tropical Demosponges: Integrative Taxonomy with Description of a New Species

In the exploration of the meiofauna associated with sponges and corals in the shallows of Cuba, we investigated nine species of sponges (Demospongia), wherein 26 nematode species were revealed. Most nematode specimens (50–95% of all individuals) in all sponge samples belonged to the family Desmodoridae (order Desmodorida), followed by the family Chromadoridae (order Chromadorida). A major part of Desmodoridae is constituted by the genus Acanthopharynx. A statistical morphometric analysis (principal component analysis and multidimensional scaling with testing via analysis of similarities) revealed two close cohorts that differed in size and pharynx shape. Molecular genetic analyses (COI, 18S, and 28S) also distinguished two groups of specimens that corresponded to morphometric cohorts. Based on the morphometry and molecular genetics, the larger-sized group was defined as Acanthopharynx micans (Eberth, 1873), while the smaller-sized group was considered A. parva sp. n. In light of the taxonomic review of the Acanthopharynx, emended generic diagnosis, and the annotated list of ten valid species, A. parva sp. n. differed from other Acanthopharynx species by its peculiar shape of the pharynx (gradually widened to cardia), smaller body size, and pattern of precloacal organs.

A new species of Aplectana Railliet & Henry, 1916 (Nematoda: Cosmocercidae) in the Brazilian Amazon and the taxonomic status of Aplectana longa.

Nematodes of the genus Aplectana Railliet & Henry, 1916 are common parasites of the digestive tract of amphibians and reptiles in the Neotropical region. During a parasite survey on Boana boans (Linnaeus, 1758), we found specimens of nematodes with Aplectana characteristics. We observed a set of characteristics that differs the species of our study from its congeners, and the present study describes a new species of Aplectana parasite of B. boans using light microscopy and scanning electron microscopy. Aplectana pella n. sp. has lateral alae and somatic papillae in males and females; males have equal short spicules, and the gubernaculum is absent. The arrangement of pairs of caudal papillae also differs from other species (2 precloacal,1 adcloacal, and 5 postcloacal+1 unpaired). In females, the vulva is simple, with non-prominent lips, and equatorial. This is the first record of the genus Aplectana parasitizing B. boans and the 58th species described for this genus. Additionally, we added the precloacal papillae pattern of A. delirae, and based on morphological and morphometric characteristics, we propose the reallocation of Aplectana longa to the genus Oxyascaris.

"Revisiting the past": a redescription of Physaloptera retusa (Nemata, Physalopteridae) from material deposited in museums and new material from Amazon lizards.

Physaloptera Rudolphi, 1819 is a genus of nematodes that includes approximately 100 species parasitic in vertebrates around the world. From these, approximately 30 occur in the Neotropical region, with nine reported from neotropical reptiles. Physaloptera spp. are recognized by their distinct morphology of the apical end and characters of the reproductive system. However, despite the fact that the morphological characters for species diagnosis have been firmly established, we frequently find identification problems regarding poorly detailed descriptions and poorly preserved specimens. These may lead to taxonomic incongruencies. Physaloptera retusa (Rudolphi, 1819) is the most common species of the genus and has been reported from several species of neotropical reptiles. Based on our reexaminations of nematode specimens identified as P. retusa from different museum collections, we provide a detailed redescription including the type material, voucher specimens and new specimens recovered currently and showed in this study with new morphological data obtained using light and scanning electron microscopy tools.

Parasitic Nematodes of Plant Persimmon (Diospyros Kaki, l.) Rhizosphere in District Swat, Kp Pakistan

Purpose: Different species of plant parasitic nematodes of persimmon (Diospyros kaki, L.) were identified from various localities of District Swat KPK Pakistan namely Chail, Madyan, Piya, Jare, Chikrai, Thesil, Fateh pur, Baghdheri, Naway kalay, Shin, Pirpatay, Sambat and Gurra. Methods: Soil samples were collected from the bases of persimmon trees along with rhizospheres that show stunted growth. The collected samples were then processed by using modified Bearmann funnel technique. Nematode specimens isolated in cavity block were killed by heat and treated with TAF (Triethylamine formaldehyde) solution. Findings and Practical implication: After 24 hours, the specimens were transferred to 1.25 % glycerin with trace amount of picric acid for staining of nematodes. Nine different species of nematodes were reported from these localities were Tylenchus spp, Psilenchus spp, Meloidogyne larvae, Aphelenchus spp, Tylenchus juveniles, Filenchus spp, Pratylenchus spp, Helicotylenchus pseudorobustus and Helicotylenchus dihystera. Helicotylenchus species were more common in the collected samples. Conclusion: It is concluded from analysis of soil samples that plant parasitic nematodes associated with persimmon cause economic loss in district swat. Persimmon plants show stunted and retarded growth in soil which has high nematode population density. Keywords: Nematodes, Persimmon, Swat, Diospyros kaki, Triethylamine formaldehyde.

Morphological Characterization of Fresh and 20-Yr-Old Fixed Nematode Specimens of Sauertylenchus Maximus (Allen, 1955) Siddiqi, 2000 Deposited in the USDA Nematode Collection from Arlington National Cemetery, VA, USA.

Sauertylenchus maximus was discovered during a survey conducted at the Arlington National Cemetery, Virginia, for the type specimens of Hoplolaimus galeatus. Besides the fresh material, the fixed specimens of S. maximus were also studied by molecular and morphological means. The morphological and morphometric characteristics of the recovered fresh material were consistent with the original and other description(s) of this species. The fixed specimens used in this study were preserved in a 3% formaldehyde and 2% glycerin solution for over 20 yr. Molecular analyses of the fresh and fixed specimens were performed using internal transcribed spacer, D2-D2 expansion segments of 28S large subunits, and 18S small subunit ribosomal DNA sequences. To our knowledge, this represents the first report of S. maximus from Virginia and the first report of a successful DNA extraction from fixed nematode specimens.

Host status of weeds for Pratylenchus coffeae

Background Populations of yam dry rot nematodes Scutellonema bradys, Pratylenchus coffeae and P. brachyurus can be sustained on weed hosts. Objective Evaluate the reaction of 10 weeds frequently found in Alagoas to P. coffeae under greenhouse conditions. Methods Two experiments were carried out in a completely randomized design, with 11 treatments, constituted of 10 weed species and the control (Dioscorea cayenensis) with eight replications. Plants were inoculated with 2,000 nematode specimens, nematode populations were evaluated in roots and soil [...]

Occurrence of Ancylostoma Caninum from a Gray Fox Urocyon Cinereoargenteus in Southeastern Mexico.

SummaryThe hookworm Ancylostoma caninum is a common nematode of wild and domestic canids worldwide. In Mexico, there are few records of helminths in wild canids, especially in the southeastern region. The aim of the present study was to examine the helminths from a gray fox Urocyon cinereoargenteus in southeastern Mexico. A road-killed female gray fox found in Merida, Yucatan, Mexico, was examined for helminths. Only nematodes were found in the intestine of the gray fox and identified using morphological studies and molecular analysis of 28S rRNA gene fragments. The characteristics exhibited by the nematode specimens were in accordance with descriptions of A. caninum: e. g. oral opening with a pair of prominent chitinous plates bearing three pairs of ventral teeth, lateral rays with a common trunk, dorsal ray divided into two branches with each branch terminating in three digitations. BLAST analysis of the 28S sequence showed similarity and coverage values of 99.8 % and 100 %, respectively, with a sequence of A. caninum from the domestic dog Canis familiaris in Australia. The genetic distance between the Australian specimen and the Yucatan specimen of A. caninum was 0.1 %, that is, they were only different in a single nucleotide. The gray fox examined in this study was found close to a rural community where A. caninum has been recorded from domestic dogs, which could be the source of infection. Our study increases the distribution of this nematode parasitizing the gray fox in Mexico and provides the first nucleotide sequence of A. caninum from the gray fox.

NEMÁTODOS ENTOMOPÁTOGENOS NATIVOS EN EL CULTIVO DE NOPAL VERDURA EN MILPA ALTA, MÉXICO

<p><strong>Background</strong>. Entomopathogenic nematodes (NEP) are found in all ecosystems. Currently, they are one of the most studied ecological alternatives for the biological control of insect pests. In Mexico, there are few reports of their presence in agricultural soils. <strong>Objective</strong>. To isolate and identify molecularly native specimens of entomopathogenic nematodes from soil samples collected in different prickly pear producing areas in Milpa Alta, Mexico City. <strong>Methodology</strong>. Isolations were obtained from soil samples using the technique of insect lure (<em>Galleria mellonella</em> or greater wax moth). Molecular techniques of the ribosomal region (ITS1+5.8S+ITS2) were performed for nematode identification. <strong>Results</strong>. Of the NEP isolates for the genus <em>Steinernema</em>, the phylogenetic analysis (ML; HKY) grouped the sequences of the isolates in the species <em>Steinernema</em> <em>texanum</em>, with 100 % similarity and 81 % similarity between isolates. For <em>Heterorhabditis</em>, the analysis (M; HKY) grouped the sequenced isolates in the species <em>Heterorhabditis</em> <em>atacamensis</em> with 97 % similarity. The results show that the NEP are widely distributed in the study region. <strong>Implications</strong>. The presence of these isolates in the cultivation of prickly pear (nopalitos) is important since they are a potential biological tool for pest management in the study zone. <strong>Conclusion</strong>. For the first time, the presence of <em>Steinernema texanum</em> and <em>Heterorhabditis atacamensis</em> is reported in soils cultivated with prickly pear in Milpa Alta, Mexico.</p>

Prevalence and Seasonality of Adult and Arrested Larvae of Gastrointestinal Nematodes of Sheep from Mashhad City, Northeastern Iran.

Background:This study was conducted to determine the prevalence and intensity of nematode infections in sheep located in northeastern Iran from Apr 2018 to Mar 2019.Methods:Gastrointestinal nematodes of 300 sheep were inspected. The season of slaughter, anatomic location where the parasite was located, the animal’s sex, infection prevalence and intensity were recorded. Seasonal differences in arrested larvae numbers also were assessed using Cochran’s Q test.Results:Overall, 4,331 adult nematode specimens were collected. Among the examined sheep, 53% (159/300) were infected with one or more nematode species. Among infected sheep, 42.8% were infected with a single species of nematode, 26.4% were infected with two species of nematodes, and 30.8% were infected with three or more species of nematodes. Marshallagia marshalli (13.3%) was the most common nematode recovered from the abomasums of infected sheep, while Trichostrongylus vitrinus (4.6%) was commonly recovered from the small intestines, and Trichuris ovis (25.6%) was commonly recovered from the large intestines. In total, 463 arrested larvae were found in the abomasums of 7.5% of infected sheep and 104 arrested larvae were found in the small intestines of 8.8% of infected sheep. A significantly higher numbers of arrested larvae were found in summer compared to autumn (P<0.001).Conclusion:Intestinal parasites continue to be a problem for sheep in northeastern Iran and additional control measures need to be explored.

Morphology, genetic characterization and phylogeny of Aplectana dayaoshanensis n. sp. (Nematoda: Ascaridida) from frogs.

Cosmocercoid nematodes are common parasites in the digestive tract of amphibians. However, our knowledge of the species diversity, genetic data and molecular phylogeny of the superfamily Cosmocercoidea are far from being well understood. In the present study, large numbers of cosmocercoid nematodes were collected from the fine-spined frog Sylvirana spinulosa (Smith) (Anura: Ranidae) and the white-spotted thigh tree-frog Polypedates megacephalus (Hallowell) (Anura: Rhacophoridae) in Guangxi Province, China. Integrated morphological and genetic evidence reveals these nematode specimens to be a new species of the genus Aplectana, A. dayaoshanensis n. sp. (Cosmocercoidea: Cosmocercidae). The molecular characterization of small ribosomal DNA (18S), internal transcribed spacer (ITS) and large ribosomal DNA (28S) of A. dayaoshanensis n. sp., together with the 28S of A. chamaeleonis (Baylis, 1929) (collected from Hyperolius kivuensis Ahl in Rwanda), were reported for the first time. Moreover, phylogenetic analyses using maximum likelihood (ML) inference based on 18S+28S and ITS sequence data, respectively, both supported the family Cosmocercidae to be a monophyletic group and the family Kathlaniidae to be a paraphyletic group. Our phylogenetic results rejected the monophyly of the genus Aplectana. The present results contribute to the knowledge of the species diversity and genetic data of cosmocercoid nematodes, and preliminarily revealed the phylogenetic relationships of the major families and some genera in the Cosmocercoidea.