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Marmosa constantiae is a species of marsupial restricted to the central portion of South America. In Brazil, it occurs in the northwestern region including five states of the Amazon, Cerrado, and Pantanal biomes. However, there is no study of the helminth fauna or helminth community structure for this marsupial. The aims of this study were to describe the species composition and to analyse the structure of the helminthic community of M. constantiae in an area of the Amazon Arc in Sinop, north of the state of Mato Grosso, Brazil. Parasites were searched in 53 specimens of this marsupial, among which 44 were infected with at least one helminth species. Parasitic helminths were counted and identified. Nine species were collected: seven nematodes, one cestode, and one acanthocephalan. The most abundant species were Gracilioxyuris agilisis , Travassostrongylus scheibelorum, Pterygodermatites sinopiensis , and Subulura eliseae. These species were the only dominant ones in the component community. No significant differences were observed in the abundance and prevalence of helminths between male and female hosts. Host body size significantly influenced helminth abundance in males. The pattern of community structure considering the infracommunities in this locality indicated more species replacement than species loss along the environmental gradient. This is the first study to report the helminth fauna and the helminth community structure of M. constantiae. [ABSTRACT FROM AUTHOR]

The spirurid nematode Thubunaea schukurovi Annaev, 1973 (Physalopteridae) is redescribed by means of light microscopy and scanning electron microscopy from Ablepharus chernovi collected in Çamlıyayla, Turkey. This is the first record of the species from this host and the first record of the genus Thubunaea from Turkey. The taxonomic status of the species of the genus Thubunaea from the Palaeacrtic and Indomalayan realms is reviewed based on their original morphological descriptions; as a result, Thubunaea dessetae Barus & Tenora, 1976, a parasite of Saara hardwickii (Gray) (Agamidae) in Afghanistan, is transferred to the genus Pseudabbreviata as Pseudabbreviata dessetae (Barus & Tenora, 1976) n. comb. Several species described in India, that is, Thubunaea singhi Deshmukh, 1969 and Thubunaea brooki Deshmukh, 1969, both from Hemidactylus brookii Gray (Gekkonidae), and Thubunaea aurangabadensis Deshmukh, 1969 and Thubunaea syedi Deshmukh, 1969, both from Hemidactylus giganteus Stoliczka, are considered members of the genus Physalopteroides ; therefore, the following new combinations are proposed: Physalopteroides singhi , Physalopteroides brooki , Physalopteroides aurangabadensis and Physalopteroides syedi. Thubunaea hemidactylae Oshmarin & Demshin, 1972 from Hemidactylus frenatus Duméril & Bibron in Vietnam is considered a member of the genus Physalopteroides as P. hemidactylae (Oshmarin & Demshin, 1972) n. comb. [ABSTRACT FROM AUTHOR]

A new species of Ancyracanthus , parasite of the electric eel Electrophorus varii , in the Brazilian Amazon, is described based on morphological and molecular characterization. Ancyracanthus electrophori n. sp. differs from the two congeners namely, Ancyracanthus pinnatifidus and Ancyracanthus schubarti , based on the structure of cephalic appendages, number and arrangement of caudal papillae in males, vulva very close to anus in females, eggs with smoothly mamillated shell, host taxon and geographical origin. Moreover, the new species is the first in the genus to be described with thorny cuticular rings and to be observed with the use of scanning electron microscopy (SEM). The morphology of A. pinnatifidus and A. schubarti is still poorly-known and should be revised in details; however, the separation between them and the new species was clear. Genetic characterization based on 28S rDNA and cytochrome c oxidase subunit I (cox 1) mtDNA partial sequences, performed for the first time in Acyracanthus , along with phylogenetic reconstructions using both genetic markers, placed Ancyracanthus electrophori n. sp. in a suggestive basal position within Gnathostomatidae. Phylogenetic reconstructions using cox 1 sequences also suggested lack of monophyly in the genera Gnathostoma and Spiroxys and, consequently, in the subfamilies Gnathostominae and Spiroxyinae. However, such results are preliminary. With the first genetic characterization and observations using SEM in Ancyracanthus , resulting in the discovery of a new species and in the expansion of the geographical occurrence of the genus to Amazonian fish, an important step towards a better understanding of these nematodes has been taken. [ABSTRACT FROM AUTHOR]

Cosmocerca spp. are common nematode parasites of amphibians. We provide herein molecular data for two species of Cosmocerca and describe a new species, Cosmocerca albopunctata n. sp., using light microscopy and molecular data (cytochrome c oxidase subunit 1 – COI mtDNA). Cosmocerca albopunctata n. sp. can be easily distinguished from other congeneric species by the combination of characteristics such as body size, length of spicules and gubernaculum, and the arrangements and number of caudal papillae (7 + 1:1 + 1:6). The phylogenetic results based on the partial COI mtDNA sequences clustered the new species in a monophyletic clade along with the other sequences of Cosmocerca spp. Therefore, our results contribute to the knowledge about the species diversity and genetic data for Cosmocerca spp. in the Neotropical region. [ABSTRACT FROM AUTHOR]

Didelphis albiventris is the opossum with the largest geographic distribution in Brazil and has a wide spectrum of helminth parasites. This study aimed to describe the species composition and analyse the structure of helminth communities of D. albiventris in two extremes of the Atlantic Forest in Brazil. The influence of host sex, body mass, age, helminth species richness and locality on the abundance and prevalence of the most prevalent helminth species was investigated. Ninety-five per cent of the animals were infected with at least one species. Nine helminth species were found: the nematodes Aspidodera raillieti, Cruzia tentaculata, Trichuris didelphis and Trichuris minuta in the large intestine; Turgida turgida in the stomach; Travassostrongylus orloffi and Viannaia hamata; and the trematodes Brachylaima advena and Rhopalias coronatus in the small intestine. Three helminth morphospecies were also recovered: the nematodes Hoineffia sp. and Viannaia sp. and a cestode in the small intestine. Cruzia tentaculata and V. hamata were the species with the highest mean abundances and intensities, while the most prevalent species were A. raillieti, C. tentaculata, T. turgida and V. hamata, forming the central nucleus of the helminth component community. The analysis of the helminth metacommunity structure indicated a Gleasonian pattern for the total set of infracommunities, corroborating the beta diversity indices, which indicated more species replacement than loss between localities and infracommunities, although at a low level. The results indicated a stronger influence of host attributes than geographical distance on the community structure. [ABSTRACT FROM AUTHOR]

Helminth infracommunities were studied at 174 sites of Latvia in seven hosts from six amphibian taxa of different taxonomical, ontogenic and ecological groups. They were described using a standard set of parasitological parameters, compared by ecological indices and linear discriminant analysis. Their species associations were identified by Kendall's rank correlation, but relationships with host size and waterbody area were analysed by zero-inflated Poisson and zero-inflated negative binomial regressions. The richest communities (25 species) were found in post-metamorphic semi-aquatic Pelophylax spp. frogs, which were dominated by trematode species of both adult and larval stages. Both larval and terrestrial hosts yielded depauperate trematode communities with accession of aquatic and soil-transmitted nematode species, respectively. Nematode loads peaked in terrestrial Bufo bufo. Helminth infracommunities suggested some differences in host microhabitat or food object selection not detected by their ecology studies. Associations were present in 96% of helminth species (on average, 7.3 associations per species) and dominated positive ones. Species richness and abundances, in most cases, were positively correlated with host size, which could be explained by increasing parasite intake rates over host ontogeny (trematode adult stages) or parasite accumulation (larval Alaria alata). Two larval diplostomid species (Strigea strigis, Tylodelphys excavata) had a negative relationship with host size, which could be caused by parasite-induced host mortality. The adult trematode abundances were higher in larger waterbodies, most likely due to their ecosystem richness, while higher larval abundances in smaller waterbodies could be caused by elevated infection rates under high host densities. [ABSTRACT FROM AUTHOR]

A new nematode species, Raphidascaris mundeswariensis n. sp. (Raphidascarididae), is described from male and female specimens found in the intestines of the mudskipper Apocryptes bato (Hamilton, 1822) (Gobiidae) from the Mundeswari River of West Bengal, India. This species is distinguished from its congeners by 214–255-μm-long spicules, 14 pairs of preanal papillae of two markedly different sizes, one pair of adanal papillae, six pairs of postanal papillae and the absence of lateral alae. Phylogenetic analyses using partial sequences of the 28S ribosomal RNA gene place the new species in a clade containing Raphidascaris gigi, Raphidascaris lophii, Raphidascaris longispicula and two species of Hysterothylacium. The molecular analyses also corroborate results of previous studies that have found Raphidascaris and Hysterothylacium to be paraphyletic. The finding of R. mundeswariensis in A. bato is the first Raphidascaris species described from a mudskipper anywhere. [ABSTRACT FROM AUTHOR]

While much attention has been paid to vector-borne filariasis, diseases that threaten millions of people in tropical and subtropical countries, the literature on host–parasite associations and transmission strategies of filarial nematodes in wildlife is scarce. Here, we report the co-occurrence of chigger mites (Eutrombicula alfreddugesi) and onchocercid nematodes (Oswaldofilaria chabaudi) parasitizing the lizard Tropidurus torquatus in the State of Minas Gerais, Brazil. Examination of chiggers established, for the first time, the occurrence of microfilariae in trombiculid mites (Trombiculidae). These larvae were morphologically similar to those recovered from adult females of O. chabaudi. The current evidence suggests that chiggers do not play a role in the transmission of filarioid nematodes, but rather act as accidental or dead-end hosts. Nevertheless, considering the polyphagous nature of trombiculid mites, similar to blood-sucking insects involved in the transmission of several infectious diseases, further studies may shed light on the potential role of chiggers as vectors of filarioids. [ABSTRACT FROM AUTHOR]

A total of 61 specimens representing five species of shag – Auckland Island shag Leucocarbo colensoi, little pied shag Microcarbo melanoleucos brevirostris, black shag Phalacrocorax carbo novaehollandiae, Otago shag Leucocarbo chalconotus and spotted shag Phalacrocorax punctatus – from the coast around Otago, South Island, New Zealand, were examined for helminths. A total of 18 helminth species was found: six nematodes (Anisakis pegreffi, Contracaecum rudolphii E, Baruscapillaria sp., Cosmocephalus jaenschi, Ingliseria cirrohamata, Desmidocercella australis), four trematodes (Apatemon sp. 'jamiesoni', Cardiocephaloides ovicorpus, Apophallus sp., Microphallidae gen. sp.), four cestodes (Microsomacanthus cormoranti, Microsomacanthus sp., Paradilepis urceina, Tetrabothrius sp.) and four acanthocephalans (Andracantha leucocarboi, A. sigma, Corynosoma hannae, Profilicollis novaezelandensis). Descriptions are provided for females of C. jaenschi and D. australis, which were previously undescribed. The data include 20 new host records and seven new locality records. New 18S ribosomal DNA and internal transcribed spacer (ITS1 and ITS2) DNA sequences have been provided where specimen conditions permitted. These data add considerably to our sparse knowledge of helminths in New Zealand shags, and provide a baseline for observations of change in the future. [ABSTRACT FROM AUTHOR]

Six species of freshwater turtles dominate the Chaco-Pampa Plain in southern South America and their parasites have been relatively understudied, with most records concentrated in Brazil. Particularly in Argentina, there are only scattered records of parasites for most of the turtles that inhabit the region, leaving a large knowledge gap. The purpose of the present contribution is to increase the knowledge of the internal parasites of six species of freshwater turtles from Argentina, after 15 years of fieldwork, by providing new hosts and additional geographic records for many host-parasite relationships. Some molecular sequences of the studied parasites were provided as a tool for better species identification. We processed 433 stomach and fecal samples from live individuals and visceral and soft tissue samples from 54 dissected turtles collected from a wide range and different ecoregions. We found 6230 helminths belonging to 18 taxa (one cestode, 11 digeneans and six nematodes). Fourteen new parasite-host associations are reported here, and for the first time parasites are recorded for Phrynops williamsi. This work contributes significantly to the knowledge of the parasitofauna in freshwater turtles in Argentina, providing a detailed list of parasites present in each turtle species and reporting molecular characters for future studies.

Hexamermis zirabi sp. n., recovered from a natural habitat of Mazandaran province, north of Iran, is described based on morphological and molecular data. The new species is characterized by its six cephalic papillae; cuticle with distinct cross fibers; conoid or sharply tapered head; mouth terminal; six hypodermal cords; J-shaped vagina oriented to the anterior end of body; uterus with Z-organs or sclerotized bodies; tail similar in both sexes and bluntly rounded; spicules paired, separate, slightly curved, shorter than body width at cloaca, with rounded tip; and male genital papillae arranged in five rows. In addition to the morphological study, molecular phylogenetic analyses using a partial large subunit (28S D2-D3) were also performed, and the new species formed a highly supported (1.00% Bayesian posterior probability (BPP)) clade with Hexamermis popilliae.

A survey for slug- and snail-associated nematodes was conducted in forests, parks, botanical gardens, and nature reserves at 13 localities in Belgium to uncover more diversity of gastropod mollusc-associated nematodes and to characterise Pellioditis populations found in the country. A total of 319 slugs and snails belonging to nine species were examined. Arion vulgaris was the most commonly found mollusc species in this study (eight locations), and 19.4% of the examined mollusc specimens were found infected by nematodes. The highest prevalence of nematodes was observed in Cornu aspersum (60%) followed by A. vulgaris (34.8%), Limax maximus (28.6%), and Cepaea sp. (20%). Eleven nematode species belonging to eight families were isolated and identified from the mollusc hosts including Alloionema appendiculatum , Angiostoma dentiferum , A. gandavense , Angiostrongylus vasorum , Cosmocerca longicauda , Panagrolaimus cf. subelongatus , Pellioditis californica , P. hermaphrodita , Rhabditis sp., Tetrameres cf. fissispina , and Troglostrongylus cf. brevior. Pellioditis was the most commonly found nematode genus (at nine localities) and C. longicauda and P. californica were reported in Belgium for the first time. Co-infections of more than one nematode species were observed in eight (2.5%) molluscs specimens. Most co-infections consisted of two nematode species. In one A. vulgaris specimen, a co-infection of three nematode species ( A. vasorum , P. hermaphrodita , and Tetrameres cf. fissispina ) was observed. Four ex vivo cultures of P. californica and six ex vivo cultures of P. hermaphrodita were established from single hermaphrodites, and both species were described based on light microscopy, scanning electron microscopy, and morphometric, morphological, and molecular data.

Free-ranging grey wolves (Canis lupus), which are presently recolonizing Italy, can be parasitized by a diversity of helminths, but have rarely been subject to studies of their parasites. Therefore, this study aims to determine the prevalence of gastrointestinal helminths of road-killed grey wolves from the Piedmont region of Italy. Forty-two wolves were collected and examined for the presence of helminths. We recorded 12 helminth species: nine Nematoda and three Cestoda. The nematodes were: Ancylostoma caninum (7.1%), Capillaria sp. (2.4%), Molineus sp. (2.4%), Pterygodermatites affinis (11.9%), Physaloptera sibirica (9.5%), Toxocara canis (9.5%), Toxascaris leonina (2.4%) and Uncinaria stenocephala (26.2%); the cestodes were: Dipylidium caninum (4.8%), Mesocestoides sp. (4.8%) and Taenia multiceps (76.2%). Physaloptera sibirica had the highest mean intensity and T. multiceps had the highest prevalence. Based on age and sex, no differences in the intensity or prevalence of helminth species were found among the hosts. Molineus sp. was recorded for the first time in wolves from the Palearctic region; P. affinis and P. sibirica are respectively reported for the first time in wolves from Europe and Italy. [ABSTRACT FROM AUTHOR]

The genus Rhabdias Stiles & Hassal, 1905 includes about 83 species of nematodes parasitic in amphibians and reptiles worldwide. Herein, we describe Rhabdias glaurungi sp. nov. from the hylid frog Scinax gr. ruber (Laurenti, 1768) in the Gunma Ecological Park, Santa Bárbara municipality, state of Pará, Brazil. This species has six small lips, an inflated cuticle along the entire body and a cup-shaped buccal capsule with smooth internal surface of its anterior part and irregularly folded internal surface of its posterior part in apical view. From the 17 valid species recognized in the Neotropical realm, the new species can be distinguished by the number of lips, the morphology and size of its buccal capsule, as well as the extent and shape of its cuticular inflation; in addition, there are molecular differences. Sequences of the mitochondrial Cytochrome c Oxidase subunit I gene strongly support the status of this form as a separate species. Molecular phylogenetic analysis shows R. glaurungi sp. nov. nested within the R. pseudosphaerocephala Kuzmin, Tkach & Brooks, 2007 species complex. Rhabdias glaurungi sp. nov. is the second species of the genus described from hosts of the family Hylidae in the Neotropical realm. We conclude that the diversity of Rhabdias within the Neotropics is likely largely underestimated. [ABSTRACT FROM AUTHOR]

A new species of the free-living nematode genus Trachactinolaimus , collected in natural habitats of northern Iran, is described, including morphological and molecular (28S-rDNA) data. Trachactinolaimus persicus sp. n. is characterized by its 1.95-2.44 mm long body, lip region weakly offset by depression and 18-20 μm wide, odontostyle 25-27 μm long, neck 540-636 μm long, pharyngeal expansion occupying one-half of the total neck length, bipartite uterus 2.6-3.9 body diameters long, vulva ( V = 49-53) pore-like, tail long and filiform in both sexes (174-223 μm, c = 10.0-13.4, c' = 5.9-7.0 in females, 165-196 μm, c = 10.7-13.8, c' = 4.6-5.8 in males), spicules 68-75 μm long, and 12-14 almost contiguous ventromedian supplements with hiatus. Molecular data supports the monophyly of the genus and the hypothesis that Dorylaimidae are the sister group of actinolaims. The taxonomy of Trachactinolaimus is updated, including diagnosis, list of species, key to their identification, and a compendium of their main morphometrics. Dominiactinolaimus is regarded as its junior synonym.

Little is known about helminth parasites of the Bismarck Archipelago, in either archaeological or modern contexts. This study presents a parasitological analysis of soil samples from Early Lapita habitation layers at Kamgot (3300-3000 BP). Evidence for the presence of pigs and dogs and the timing of their arrival in Early Lapita contexts have been contested in the literature. The finding of parasite eggs in samples from Kamgot supports the presence of pigs and dogs at the site. Six types of helminth eggs were identified: pig nematode Trichuris suis , dog nematode Toxocara canis, and cestode Dipylidium caninum , as well as two unknown trematodes and a possible anoplocephalid cestode, thereby indicating the local presence of other mammals or birds. This study represents the first confirmed record of ancient helminth parasites in tropical Oceania.

Semperula wallacei (Issel, 1874) is a species of terrestrial slug that occurs in southeast China and the Pacific Basin and is the only species of its genus that occurs beyond the Oriental region and to the east of Wallace's line in the Australian region, where it has probably been introduced. In this study, we report for the first time S. wallacei as an intermediate host for Angiostrongylus cantonensis (Chen, 1935) based on histological and molecular analyses of slugs from Tuamasaga, Samoa, deposited at the Medical Malacological Collection (Fiocruz-CMM). DNA was obtained from the deparafinized tissues scraped from specimen slides. Polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) targeted to the internal transcribed spacer 2 ( ITS2 ) region were carried out using the restriction enzyme Cla I. The RFLP profile observed for our larval specimen of S. wallacei was identical to the profile previously established for A. cantonensis , demonstrating that S. wallacei can be naturally infected with A. cantonensis and is likely to be an intermediate host for this parasitic nematode species in the field. The potential for geographical range expansion of S. wallacei in the Pacific Basin, its small size, and the general role of veronicellids as crop pests and hosts of nematodes, indicate the significance of S. wallacei as an invasive species in the Pacific Basin. Our work also highlights the importance of biological collections for investigating the environmental impact of invasive species on agriculture, public health, and biodiversity conservation.

The Australasian harrier Circus approximans , a native of Australia, New Zealand and the South Pacific, is an opportunistic hunter of small prey, although a large part of its diet consists of carrion, mainly from roadkill. Besides a record of a single, unnamed species of capillariid nematode there have been no investigations into the parasites of Australasian harriers in New Zealand. In this study, a helminthological survey of sixty-five deceased harriers from southern New Zealand uncovered a gastrointestinal helminth fauna consisting of six parasite species. Porrocaecum circinum (Nematoda) was previously described only from fragmented females, and a redescription is presented here. Procyrnea fraseri n. sp. (Nematoda) is described, and distinguished from its congeners by its slender body shape and shorter spicules. Strigea falconis (Trematoda) is reported for the first time in New Zealand. Cladotaenia anomalis (Cestoda) and Polymorphus circi (Acanthocephala) were previously described as new species elsewhere. An unnamed species of capillariid appears to be mainly confined to North Island and is rare in South Island. Prevalence and intensity metrics are given, and DNA sequences provided to accompany new re/descriptions. Potential intermediate hosts are discussed, and the origins of the helminths and their potential for pathogenicity are considered.

Cyathostoma lari is a parasite of the nasal and orbital sinuses of gulls and other hosts in Europe and Canada. Here, we provide an overview of previously published data on the prevalence and infection intensity of C. lari in gulls. Furthermore, based on our data, we analyze the spatiotemporal trends in the prevalence and intensity of infection by C. lari in Chroicocephalus ridibundus in Czechia (central Europe; data from 1964 to 2014) and compare them with those obtained from five species of gulls in Karelia (Northwest Russia; data from 2012-2020). Based on our preliminary observations, we hypothesized that C. lari is subject to a decline in certain regions, but this decline is not necessarily applicable throughout its distribution range. We found that the C. lari population crashed in specific parts of its distribution range. The reasons are unknown, but the observed population changes correspond with the diet switch of their core host in Czechia, C. ridibundus. We previously observed a diet switch in Czech C. ridibundus from earthworms (intermediate hosts of C. lari ) to other types of food. This diet switch affected both young and adult birds. Nevertheless, it may not necessarily affect populations in other regions, where they depend less on earthworms collected from agrocenoses affected by agrochemicals and trampling. Correspondingly, we found that these changes were limited only to regions where the gulls feed (or fed) on arable fields. In Karelia, where arable fields are scarce, gulls likely continue to feed on earthworms and still display high infection rates by C. lari. Therefore, C. lari , a parasite of the nasal and orbital sinuses of gulls, nearly disappeared from their central European nesting grounds but is still present in better-preserved parts of its distribution range.

Climate change is expected to affect parasitic nematodes and hence possibly parasite-host dynamics and may have far-reaching consequences for animal health, livestock production, and ecosystem functioning. However, there has been no recent overview of current knowledge to identify how studies could contribute to a better understanding of terrestrial parasitic nematodes under changing climates. Here we screened almost 1,400 papers to review 57 experimental studies on the effects of temperature and moisture on hatching, development, survival, and behaviour of the free-living stages of terrestrial parasitic nematodes with a direct life cycle in birds and terrestrial mammals. Two major knowledge gaps are apparent. First, research should study the temperature dependency curves for hatching, development, and survival under various moisture treatments to test the interactive effect of temperature and moisture. Second, we specifically advocate for more studies that investigate how temperature, and its interaction with moisture, affect both vertical and horizontal movement of parasitic nematodes to understand infection risks. Overall, we advocate for more field experiments that test environmental effects on life-history traits and behaviour of parasitic nematodes in their free-living stages under natural and realistic circumstances. We also encourage studies to expand the range of used hosts and parasitic nematodes because 66% of results described in the available studies use sheep and cattle as hosts and 32% involve just three nematode species. This new comprehension brings attention to understudied abiotic impacts on terrestrial parasitic nematodes and will have broader implications for livestock management, wildlife conservation, and ecosystem functioning in a rapidly warming climate.

Among the Brazilian marsupials, the species of the genus Didelphis are the most parasitized by helminths. This study aimed to describe the species composition and to analyse the helminth communities of the Atlantic Forest common opossum Didelphis aurita at infracommunity and component community levels using the Elements of Metacommunity Structure Analysis, considering peri-urban, sylvatic and rural environments in the state of Rio de Janeiro, Brazil. Seventy-three specimens of D. aurita were captured during the study. Fourteen species of helminths were collected: nine of the phylum Nematoda (Trichuris minuta , Trichuris didelphis , Globocephalus marsupialis , Heterostrongylus heterostrongylus , Travassostrongylus orloffi , Viannaia hamata , Aspidodera raillieti , Cruzia tentaculata and Turgida turgida); four of the phylum Platyhelminthes (three species of Trematoda, Duboisiella proloba , Brachylaima advena and Rhopalias coronatus , and one species of the class Cestoda); and one species of the phylum Acanthocephala (Oligacanthorhynchus microcephalus). More than 95% of the animals were infected with parasites. The most abundant parasite species were V. hamata , T. turgida , C. tentaculata and T. orloffi. The nematodes T. turgida , C. tentaculata and A. raillieti were the most dominant species in the three environments. The analysis of the metacommunity structure indicated a structured pattern as a function of the environmental gradient, but only when all localities were considered together. At the infracommunity and component community levels, quasi-nested and nested structures with stochastic species loss were observed, respectively. The results indicate that the settlement of helminth species in the opossums can be attributed to the heterogeneity among individual hosts in relation to their exposure to parasites and to extrinsic factors, which vary among habitats, considering a regional scale. On a local scale, the characteristics of this host species may promote homogenization among individual hosts in terms of their exposure to the helminths. This study constitutes a new host record for the species G. marsupialis and T. didelphis and represents a pioneering investigation of the helminth metacommunity of a Neotropical marsupial. [ABSTRACT FROM AUTHOR]

The application of integrative taxonomic approaches is useful to species delineation based on a combination of distinct types of characters, here morphological features and ribosomal DNA sequences. In this study, we surveyed ectoparasitic nematodes of the subfamily Merliniinae in cultivated and natural environments in Iran. Results of morphological and morphometrical studies, light and scanning electron microscopic observations, and molecular analyses allowed us the identification of fourteen known and one unknown species including representatives of the genera Amplimerlinius (five species), Geocenamus (one species), Merlinius (three species), Nagelus (two species), Paramerlinius (one species), Scutylenchus (two species), and Telomerlinius (one species). The unknown species, Scutylenchus sp., characterized by having 35-50 incisures at mid-body; lateral field with 6 longitudinal incisures; lip region slightly offset by a constriction, flattened at front end; bearing 5-7 annuli; cephalic framework not refractive; stylet robust, 18.3-27 μm long; post anal intestinal sac absent; tail elongate conical, dorsally convex, with 24 (19-28) annuli in ventral side, ending to a smooth terminus and males common; spicules 24.5-31 μm long. The phylogenetic analyses were carried out using molecular data from nuclear ribosomal DNA (rDNA) genes viz. D2-D3 expansion segments of the large ribosomal subunit (28S rRNA), partial small ribosomal subunit (18S rRNA), and internal transcribed spacer (ITS). The molecular variability of D2-D3 expansion segments of the 28S rRNA and partial 18S rRNA was low in this family in comparison to the ITS region, which could be a more helpful molecular marker in species and genus identification.

During a survey of soil nematodes in 2022, a new species of the genus Longidorus , described here as Longidorus zanjanensis sp. nov., was discovered in the rhizosphere of Astragalus sp. in Zanjan Province, Iran. The new needle nematode is described and illustrated based on morphological, morphometric, and molecular traits. Further, its females are characterized by having a long body ranging 5.6-7.7 mm long, lip region anteriorly flattened and almost continuous or slightly offset by a depression with body contour, ca 16.5-18.5 μm wide, amphidial fovea pouch-like without basal lobes, guiding ring at 35-41 μm distance from the anterior end, and an odontostyle and odontophore ranging 102-115 and 47-75 μm long, respectively. The pharyngeal bulb is 123-153 μm long, female reproductive system didelphic-amphidelphic containing sperm, vulva almost equatorial, located at 46.7-51.4% of body length, tail short, rounded to bluntly conoid, bearing two pairs of caudal pores and terminus widely rounded with distinct radial lines in hyaline region (39-50 μm long, c = 122.4-189.4, c' = 0.6-0.8). Males are common, making up to 60% of the adults, and are functional, with spicules 68.0-80.0 μm long, as well as having 8-14 ventromedian copulatory supplements. All four juvenile life developmental stages were present, with the tail of first-stage juvenile conoid shape, dorso-ventrally curved with rounded terminus. The polytomous codes delimiting the new species are: A4-B3-C3-D3-E1-F34-G12-H1-I2-J1-K6. Morphologically, the new species comes close to eight known species of the genus, namely L. apulus , L. armeniacae , L. crassus , L. kheirii , L. soosanae , L. proximus , L. pauli, and L. ferrisi. The morphological differences between the new species and the aforementioned species are discussed. Molecular phylogenetic analyses based on D2-D3 of large subunit (LSU) and internal transcribed spacer 1 (ITS1) rRNA sequences indicate that Longidorus zanjanensis sp. nov. is closely related to L. hyrcanus , L. soosanae , and L. elongatus.

During a survey on the soil nematodes, a population of the genus Aphelenchoides was collected around the rhizosphere of persimmon in Guilan Province, Iran. The morphological and molecular characters confirmed the new species, namely A. persicus sp. n. The new species is characterized by a female body length (699-1068 μm), lip region offset from the rest of the body by a slight constriction, lateral fields with six incisures, stylet 12-13.5 μm long, with a clear basal swelling, excretory pore ca 1.5 metacorpal length posterior to base of the metacorpus, post uterine sac elongate, about 4-7 times than the vulval body diameter; conical female tail with a single centrally located mucron with tiny projection close to the tail tip, male body length (663-908 μm), and spicule well developed with rounded condylus, blunt conical rostrum, and a hook-like tip of dorsal limb. The new species belongs to the Group 2 category of Aphelenchoides species and was similar to seven known species with six lateral field incisures, including A. allius , A. chinensis , A. meghalayensis , A. nechaleos , A. paranechaleos , A. parasexlineatus , and A. sexlineatus. The molecular phylogeny based on 28S rDNA revealed that the new species stands close to A. hamospiculatus (MN931591; MN931592) and two unidentified Aphelenchoides (KY769057; LC583315). The measurements, line illustrations, LM photographs, and phylogenetic analysis are given for the new species.

A total of 235 vials of nematodes held in the Australian Helminthological Collection of the South Australian Museum from 125 individuals of Isoodon macrourus were examined. The nematode assemblage of I. macrourus , comprising 12 families, including 16 genera and 23 identified species, was compared with the sympatric bandicoot species Perameles nasuta , 20 identified species (Sorensen's index of similarity 0.56) and P. pallescens , 12 identified species (Sorensen's index 0.51). Sprattellus cassonei n. sp. is distinguished from its congeners by having a synlophe with 7-8 ridges with the anterior ventral ridges interrupted, the morphology of the dorsal ray and the branching of the spicule tips. A single male specimen identified as Linstowinema sp. 1. is characterised by seven circles of body hooks, the oesophagus terminating at the level of the seventh circle and robust scale-like spines on the posterior ventral body. A complete description of the species will require additional material, including females. Difficulties in identifying individuals of the genus Mackerrastrongylus to species level are discussed. Overall similarities in the nematode assemblages of the three bandicoot hosts are likely due to shared relationships and similar behaviours.

A new species belonging to the genus Laimydorus , and a known species of the genus Labronema , collected from the rhizosphere of grassland plants in West Azarbaijan province, Iran, are presented. The new species is characterized by its body length (1.56-1.81 mm in females and 1.39-1.57 mm in males), lip region offset by weak constriction and wider than adjacent body (11-14 μm), odontostyle 17-20 μm long, neck length 312-434 μm, vulva longitudinal (V = 42.2-46.5), uterus well-developed and with Z-differentiations, tail long (219-237 μm, c = 6.9-8.3, c´ = 8.2-10) in females, short and convex-conoid with blunt terminus (19-22 μm, c = 68-72.5, c´ = 0.77-0.84) in males, spicules 40-45 μm long, and 18-20 contiguous ventromedian supplements with hiatus. Molecular analyses, using Bayesian inference based on D2-D3 expansion segments of the 28S rRNA (LSU), placed the new species in a clade comprising representatives of the genera Nevadanema , Dorylaimus , Labronema , Calcaridorylaimus , Mesodorylaimus , and Prodorylaimus , which all belong to Dorylaimidae. In addition, new data (molecular, morphometrics, images, and geographic distribution) are presented for the Iranian population of Labronema vulvapapillatum.

Nodular roundworms ( Oesophagostomum spp.) are frequent parasites of the large intestine in several mammal species including humans and pigs, and their study often requires the use of infective larvae produced using several coproculture techniques. However, there is no published comparison of techniques to determine which yields the highest number of larvae. This study compares the number of larvae recovered from coprocultures made with charcoal, sawdust, vermiculite, and water in an experiment repeated twice using feces from a sow naturally infected with Oesophagostomum spp. at an organic farm. A higher number of larvae were recovered from coprocultures using sawdust relative to other types of media used, and this was consistent across the two trials. The use of sawdust to culture Oesophagostomum spp. larvae is rarely reported and our study suggests it can yield higher numbers relative to other media.

To gain insights into the trichurid diversity in pre-Hispanic remains of South American camelids (SACs), as well as into modern SAC populations, a bibliographic search was carried out to find parasitological studies. Results showed that a total of 17 studies were performed at archaeological and paleontological sites, in which a total of 213 samples were examined. The sample set was used as the unit of analysis, and 83% of 52 pre-Hispanic sample sets were positive for parasites. Parasitological studies confirmed the pre-Hispanic presence of diverse trichurids: two Trichuris species and capillariid eggs with morphological differences that allowed them to be assigned to three different species. Currently, the richness of the native trichurid assemblages in SACs has been extended by the inclusion of two species ( Trichuris sp. 2 and Capillariinae gen. sp. 1). Modern T. tenuis Chandler, 1930, considered SAC-specific, would have invaded SAC populations during the European colonization. The estimate of regional and temporal trichurid prevalence and paleoecological information allowed us to propose a possible origin for some of them. Although the present analysis is exploratory, it should stimulate future studies about the biogeographic history of SAC helminths, provide relevant information to improve descriptions of the Holocene ecology, and identify threatened helminths.

The evolutionary relationships of the nematode genus Loofilaimus are explored with an integrative approach, combining morphological and molecular (28S-rDNA) data. Never recorded since its original description in 1998, the finding of fresh specimens of its type and only species, L. phialistoma , allowed us to obtain SEM observations and sequencing, both for the first time, resulting in relevant aspects to elucidate its phylogeny. Morphologically, the genus is characterized by two autapomorphies affecting its lip region and pharynx. Molecular study revealed that it represents a very restricted evolutionary trend within Dorylaimida. The clade (Nygolaimina + ( Loofilaimus + Dorylaimina)) is well supported. Loofilaimidae is accepted as a separate and valid family, which should also include Bertzuckermania.

Some slug species are considered a nuisance in agriculture and horticulture worldwide, causing economic losses to growers. Phasmarhabditis is a genus of bacteria-feeding nematodes that can parasitize slugs and snails and thus potentially serve as a biological control agent. Canada had no record of Phasmarhabditis until a survey conducted in 2019 reported a Canadian strain of Phasmarhabditis californica from a single Arion rufus slug. To build on this discovery, we surveyed three major agricultural sites, ten greenhouses, and nurseries in Alberta from June to September 2021 to collect pest slug species and investigate their associated nematodes, specifically P. californica. Slugs were collected from the field and returned to the laboratory to check for emerging nematodes on White traps. We collected 1331 slugs belonging to nine species, with Deroceras reticulatum being the most common. Only 45 (3.38%) slug samples were positive for nematodes, and the majority were identified to species level: Alloionema appendiculatum, Caenorhabditis briggsae, Caenorhabditis elegans, Panagrolaimus subelongatus, and Mesorhabditis spiculigera. We did not isolate P. californica from any of the slugs collected from these survey sites, which included the original site where P. californica was discovered. However, four D. reticulatum slugs retrieved from a residential garden sample were infected with P. californica. These findings suggest the possibility of a fragmented distribution of P. californica across Alberta. Future research should focus on extensively surveying agriculture and horticulture sites and residential gardens in different provinces across Canada.