Three new species of free-living marine nematodes of the Microlaimus genus (Nematoda: Microlaimidae) from the continental shelf off northeastern Brazil (Atlantic Ocean)

Three new species of the Microlaimus genus (Nematoda: Microlaimidae) are described from sample sediments collected in the South Atlantic, along the Continental Shelf break of Northeastern Brazil. Microlaimus paraundulatus sp. n. possesses four setiform cephalic sensillae, a buccal cavity with three small teeth, arched and slender spicules and a wave-shaped gubernaculum. Microlaimus modestus sp. n. is characterized by four small cephalic sensillae, a buccal cavity with three teeth (one large dorsal tooth), cephalated spicules and a strongly arched gubernaculum in the distal region. Microlaimus nordestinus sp. n. is characterized by the following set of features: relatively long body, eight rows of hypodermal glands that extend longitudinally along the body and a funnel-shaped gubernaculum surrounding the spicules at the distal end. An amendment of the diagnosis is proposed for the genus.

Paracapillaria (Ophidiocapillaria) siamensis sp. nov. (Nematoda: Trichuroidea): a new nematode in Naja kaouthia from Thailand

A comprehensive investigation, incorporating both morphological and molecular analyses, has unveiled the existence of a hitherto unknown nematode species, Paracapillaria (Ophidiocapillaria) siamensis sp. nov., residing in the intestine of the monocled cobra, Naja kaouthia, in the central region of Thailand. This study integrates morphological characteristics, morphometric examination, scanning electron microscopy and molecular phylogenetic analysis (COI, 18S rRNA and ITS1 genes). The findings place the newly described species within the subgenus Ophidiocapillaria, elucidating its distinctive characteristics, including a frame-like proximal spicule shape, approximate lengths of 19 000 and 22 500 μm with approximate widths of 90 and 130 μm for males and females, 39‒45 stichocytes, elevated lips without protrusion, a dorsal bacillary band stripe with an irregular pattern of bacillary cells and evidence of intestinal infection. These features serve to differentiate it from other species within the same subgenus, notably Paracapillaria (Ophidiocapillaria) najae De, , a species coexisting P. siamensis sp. nov. in the monocled cobra from the same locality. This study addresses the co-infection of the novel species and P. najae within the same snake host, marking the second documented instance of a paracapillariid species in the monocled cobra within the family Elapidae. The genetic characterization supports the formal recognition of P. siamensis sp. nov. as a distinct species, thereby underscoring its taxonomic differentiation within the Capillariidae family. This research identifies and characterizes the new nematode species, contributing valuable insights into the taxonomy of this nematode.

Feeding-structure morphogenesis in "rhabditid" and diplogastrid nematodes is not controlled by a conserved genetic module

Disentangling the evolution of the molecular processes and genetic networks that facilitate the emergence of morphological novelties is one of the main objectives in evolutionary developmental biology. Here, we investigated the evolutionary history of a gene regulatory network controlling the development of novel tooth-like feeding structures in diplogastrid nematodes. Focusing on NHR-1 and NHR-40, the two transcription factors that regulate the morphogenesis of these feeding structures in Pristionchus pacificus, we sought to determine whether they have a similar function in Caenorhabditis elegans, an outgroup species to the Diplogastridae which has typical "rhabditid" flaps instead of teeth. Contrary to our initial expectations, we found that they do not have a similar function. While both receptors are co-expressed in the tissues that produce the feeding structures in the two nematodes, genetic inactivation of either receptor had no impact on feeding-structure morphogenesis in C. elegans. Transcriptomic experiments revealed that NHR-1 and NHR-40 have highly species-specific regulatory targets. These results suggest two possible evolutionary scenarios: either the genetic module responsible for feeding-structure morphogenesis in Diplogastridae already existed in the last common ancestor of C. elegans and P. pacificus, and subsequently disintegrated in the former as NHR-1 and NHR-40 acquired new targets, or it evolved in conjunction with teeth in Diplogastridae. These findings indicate that feeding-structure morphogenesis is regulated by different genetic programs in P. pacificus and C. elegans, hinting at developmental systems drift during the flap-to-tooth transformation. Further research in other "rhabditid" species is needed to fully reconstruct the developmental genetic changes which facilitated the evolution of novel feeding structures in Diplogastridae.

Three new species of Ascarophis van Beneden, 1871 (Nematoda: Cystidicolidae) from deep-sea hydrothermal vent fishes of the Pacific Ocean

Examinations of some deep-sea hydrothermal vent fishes from the western and eastern regions of the Pacific Ocean revealed the presence of three new species of Ascarophis van Beneden, 1871 (Nematoda: Cystidicolidae), all gastrointestinal parasites, namely: A. justinei n. sp. from Thermarces cerberus Rosenblatt & Cohen (type host) and Thermichthys hollisi Cohen, Rosemblatt & Moser (both Zoarcidae, Perciformes) and A. globuligera n. sp. from T. cerberus from the Northern East Pacific Rise, and A. monofilamentosa n. sp. from Pyrolicus manusanus Machida & Hashimoto (Zoarcidae, Perciformes) from the Manus Basin near Papua New Guinea. Specimens are described and illustrated based on light and scanning electron microscopical examinations. In addition to other morphological differences, all the three new species differ from each other by the structure of eggs: eggs bearing a lateral superficial swelling (A. globuligera n. sp.), eggs with one conspicuously long filament on one pole (A. monofilamentosa n. sp.) and eggs smooth, without any filaments or swellings (A. justinei n. sp.). The egg morphology of the two first-named species is unique within all species of Ascarophis, which indicates that all the three newly described species of Ascarophis are probably endemic to the respective hydrothermal vents as their fish hosts.

Corononema vulgare sp. n. and Hofmaenneria coralis sp. n. (Nematoda, Monhysterida) from coral reefs off the coast of Vietnam

Two new nematode species of the order Monhysterida, found in coral reefs on the coast of Vietnam, are described and illustrated. Corononema vulgare sp. n. morphology is similar to C. thai Nicholas & Stewart, 1995 but differs from it by the shorter outer labial setae, shorter tail in males, and a different shape of the guiding lateral bodies in the spicular apparatus of males. Hofmaenneria coralis sp. n. morphology is close to H. niddensis Gerlach & Meyl, 1957 and H. optata Alekseev, 1983. The new species differs from the first species by having thinner body, a shorter and less slender tail, and shorter spicules. The new species differs from H. optata in having a longer body, shorter pharynx, shorter tail, and longer outer labial setae.

A redescription of Hedruris moniezi Ibáñez & Córdova, 1976 (Nematoda: Hedruridae), an endoparasite of the Titicaca water frog Telmatobius culeus (Garman, 1876) (Anura: Telmatobiidae), with comments on all other known Hedruris species in Peru

Hedruris moniezi Ibáñez & Córdova, 1976 (Nematoda: Hedruridae) was described using light and scanning electron microscopy (SEM) based on specimens collected from the stomach of Telmatobius culeus (Anura: Telmatobiidae) in Peru. We observed some characteristics not reported previously, including sessile and pedunculated papillae and amphid on the pseudolabia, bifid deirids, morphology of the retractable chitinous hook, morphology and arrangement of the plates on ventral surface of the posterior end of the males, and arrangement of caudal papillae. Telmatobius culeus represents a new host of H. moniezi. In addition, H. basilichtensis Mateo, 1971 is considered to be a junior synonym of H. oriestae Moniez, 1889. A key to valid species of Hedruris in Peru is provided.

Arthrostoma leucurus sp. n. (Nematoda: Ancylostomatidae), A New Hookworm Species Isolated from Asian Badger in China

Purpose

To date, ten validated Arthrostoma species were reported. Here, a new hookworm species was found from Asian badger (Meles leucurus).

Methods

Nineteen hookworms (9 males and 10 females) were collected from the small intestine of two Asian badgers in Xinjiang Uygur Autonomous Region, northwestern China. The hookworms were morphologically examined according to key taxonomic characters, such as anterior extremity direction, structures of oral opening (cutting plates or teeth), vulva location, buccal capsule anatomy (integrated or formed by articulating plates), the length of spicule and gubernaculum, number of plates of buccal capsule, and presence or absence of vulvar papillae.

Results

The hookworm species from Asian badger, here named as Arthrostoma leucurus sp. n., was different from the previously described ten Arthrostoma species. The phylogenetic tree based on the cox1 gene showed that Arthrostoma leucurus sp. n. formed a separate clade, as a sister group to Ancylostoma and Uncinaria species.

Conclusion

Arthrostoma leucurus sp. n., the eleven validated Arthrostoma species, was identified from Asian badger in China.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11686-022-00587-5.

Ancestral morphology of Ecdysozoa constrained by an early Cambrian stem group ecdysozoan

BACKGROUND

Ecdysozoa are the moulting protostomes, including arthropods, tardigrades, and nematodes. Both the molecular and fossil records indicate that Ecdysozoa is an ancient group originating in the terminal Proterozoic, and exceptional fossil biotas show their dominance and diversity at the beginning of the Phanerozoic. However, the nature of the ecdysozoan common ancestor has been difficult to ascertain due to the extreme morphological diversity of extant Ecdysozoa, and the lack of early diverging taxa in ancient fossil biotas.

RESULTS

Here we re-describe Acosmia maotiania from the early Cambrian Chengjiang Biota of Yunnan Province, China and assign it to stem group Ecdysozoa. Acosmia features a two-part body, with an anterior proboscis bearing a terminal mouth and muscular pharynx, and a posterior annulated trunk with a through gut. Morphological phylogenetic analyses of the protostomes using parsimony, maximum likelihood and Bayesian inference, with coding informed by published experimental decay studies, each placed Acosmia as sister taxon to Cycloneuralia + Panarthropoda-i.e. stem group Ecdysozoa. Ancestral state probabilities were calculated for key ecdysozoan nodes, in order to test characters inferred from fossils to be ancestral for Ecdysozoa. Results support an ancestor of crown group ecdysozoans sharing an annulated vermiform body with a terminal mouth like Acosmia, but also possessing the pharyngeal armature and circumoral structures characteristic of Cambrian cycloneuralians and lobopodians.

CONCLUSIONS

Acosmia is the first taxon placed in the ecdysozoan stem group and provides a constraint to test hypotheses on the early evolution of Ecdysozoa. Our study suggests acquisition of pharyngeal armature, and therefore a change in feeding strategy (e.g. predation), may have characterised the origin and radiation of crown group ecdysozoans from Acosmia-like ancestors.

Description of Crenosoma vismani n. sp., parasitic in the lungs of Lynx lynx (L.) (Carnivora: Felidae), with identification key to the species of the genus Crenosoma Molin, 1861 (Nematoda: Crenosomatidae)

A new species of Crenosoma Molin, 1861 is described from the lungs of the Eurasian lynx, Lynx lynx (L.) (Carnivora: Felidae). Crenosoma vismani n. sp. differs from other species of the genus in the morphology of the male copulatory organs (two ventral rays originating from a common stem; three lateral rays with common stem; gubernaculum 79-92 μm long, well developed, spoon-shaped; spicules 232-253 μm long, slightly curved, with robust dorsal appendage) and a vulva with rounded, prominent vulvar cuticular appendage is located in middle region of body in females. An analysis of the morphology and life-cycle data for Crenosoma petrowi Morozov, 1939 from Ursus americanus Pallas indicate that this nematode should be described as a new species. The validity of Crenosoma schulzi Gagarin, 1958 is resurrected. A new identification key for the species of Crenosoma is provided. Published records of the genus Crenosoma from definitive hosts and patterns of host specificity are presented. Morphological data revealed that the genus Crenosoma should contain 15 species (14 with valid names) with different host specificity, ranging from oioxenous to euryxenous. However, a review of the current genetic data indicates that the actual number of Crenosoma spp. is greater, and the host range is still unknown, even in Europe.

Intraguild predation between Pristionchus pacificus and Caenorhabditis elegans: a complex interaction with the potential for aggressive behaviour

The related nematodes Pristionchus pacificus and Caenorhabditis elegans both eat bacteria for nutrition and are therefore competitors when they exploit the same bacterial resource. In addition to competing with each other, P. pacificus is a predator of C. elegans larval prey. These two relationships together form intraguild predation, which is the killing and sometimes eating of potential competitors. In killing C. elegans, the intraguild predator P. pacificus may achieve dual benefits of immediate nutrition and reduced competition for bacteria. Recent studies of P. pacificus have characterized many aspects of its predatory biting behaviour as well as underlying molecular and genetic mechanisms. However, little has been explored regarding the potentially competitive aspect of P. pacificus biting C. elegans. Moreover, aggression may also be implicated if P. pacificus intentionally bites C. elegans with the goal of reducing competition for bacteria. The aim of this review is to broadly outline how aggression, predation, and intraguild predation relate to each other, as well as how these concepts may be applied to future studies of P. pacificus in its interactions with C. elegans.

First record of Procyrnea sp. (Nematoda: Habronematidae) in Buteogallus schistaceus (Sundevall) (Accipitriformes: Accipitridae) in Brazilian Amazon

Buteogallus schistaceus (Sundevall) is an endemic bird of prey from the Amazon region, with a declining population according to international conservation agencies. The objective of this study was to report the occurrence of a parasitic nematodes in an individual treated at the Ambulatório de Animais Silvestres of Universidade Federal Rural da Amazônia, Belém campus. The animal was captured on campus and showed no resistance to capture. Fluid therapy and deworming were made, later the bird regurgited ten nematodes identified as belonging to the genus Procyrnea Chabaud (1958). Reviewing the scientific literature, it was found that so far there are no records on the helminth fauna of this bird species, which is therefore the first report of a nematode in B. schistaceus.

Comparison of ITS-2 rDNA nemabiome sequencing with morphological identification to quantify gastrointestinal nematode community species composition in small ruminant feces

Mixed gastrointestinal nematode (GIN) infections are a common and significant cause of financial loss for small ruminant producers. Morphologic examination of third-stage larvae (L₃) can be used to identify species composition in feces but has limitations due to the requirement for specialized expertise and the extensive time (8-15 d depending on method used) and labour involved. Moreover, differential development and survival of larvae during coproculture to the third stage often occurs. Deep amplicon sequencing of the ITS-2 rDNA locus of first-stage larvae (L₁) allows for higher throughput with reduced specialist labour and reduces the risk of misidentification. Harvesting of L₁ soon after hatching is also faster and further reduces labour as well as biases that can occur due to differential larval development and survival. This study compares the results of morphologic examination of L₃ with those of ITS-2 rDNA deep amplicon sequencing of L₁ from a set of pooled fecal samples. The proportions of eggs that were successfully recovered as larvae following culture to L₃ and L₁ were also compared. Larval recovery rate was significantly lower from L₃ cultures than from L₁ cultures (p < 0.001); eggs were 238.7 times less likely to develop to L₃ than to L₁ (95 % confidence interval for odds ratio 80.0-712.0). Significantly lower proportions of Teladorsagia circumcincta (odds ratio = 3.1, p = 0.008) and higher proportions of Trichostrongylus spp. (p = 0.009) were identified using morphologic examination of L₃ compared with deep amplicon sequencing of L₁ on the same samples. This is consistent with previous reports of differential survival of these species in L₃ cultures. These results indicate that deep amplicon sequencing of L₁ may reduce bias introduced by differential GIN survival to L₃ in small ruminants.

Morphological and Molecular Identification of Two Florida Populations of Foliar Nematodes (Aphelenchoides spp.) Isolated From Strawberry With the Description of Aphelenchoides pseudogoodeyi sp. n. (Nematoda: Aphelenchoididae) and Notes on Their Bionomics

Two Florida populations of foliar nematodes were collected from strawberries originating from Cashiers, North Carolina (USA) located west from Willard, the type locality of Aphelenchoides besseyi. Both nematodes were cultured on Monilinia fructicola and identified using morphological characteristics and molecular assays as Aphelenchoides besseyi and Aphelenchoides pseudogoodeyi sp. n., a herein described new species related to Aphelenchoides goodeyi belonging to the Group of Aphelenchoides exhibiting stellate tails. The morphological and biological characters of Florida A. besseyi fit those of the original description of this species. A. pseudogoodeyi sp. n., which was initially misidentified as Aphelenchoides fujianensis, differed from the type population of the latter species from China because it was without males, and females lacked a functional spermatheca, whereas type A. fujianensis is an amphimictic species. Phylogenetic analyses using near full-length 18S ribosomal RNA (rRNA), the D2-D3 expansion fragments of 28S rRNA, and partial COI gene sequences indicated that A. besseyi is a species complex. A. pseudogoodeyi sp. n. grouped in different clades from those of the type A. fujianensis, instead merging with populations identified of 'A. fujianensis' from Brazil and other countries, suggesting that the latter are conspecific and incorrectly identified. The Florida A. besseyi infected strawberry and gerbera daisy, but not soybean and alfalfa. A. pseudogoodeyi sp. n. is mainly mycetophagous. Localized inoculation of 300 specimens applied with filter paper adhering to the blade of the soybean leaves resulted in nematode penetration into the mesophyll with subsequent development of lesions limited to the inoculated area of the blade.

Trade-offs between life-history traits in a coldwater fish in the Mediterranean Sea: the case of blue whiting Micromesistius poutassou

A combination of traditional and emerging methodologies was used to assess the trade-offs between several life-history traits (linked to reproduction and condition) and parasitism in a commercially-exploited cold-water species, blue whiting Micromesistius poutassou, in the Mediterranean Sea. The use of histological and gravimetric methods revealed conflicting evidence as to the fecundity type (indeterminate or determinate) of this species. Moreover, there seem to be condition-mediated compensations between egg quality and egg quantity. The effects of parasitism on reproduction and condition are species-specific and occur mainly at high intensities of infection; they include a lower batch fecundity (affecting reproductive potential), a higher hepatosomatic index and a higher spleen-somatic index. Considering the fact that larger fish spawn more eggs and that the minimum landing size is lower than the size at maturity, these results may have implications for the future management of M. poutassou stocks in the Mediterranean Sea. Local environmental conditions may account for geographical differences regarding infection in M. poutassou. Altogether, the results support the idea that the complex trade-offs between parasitism, reproduction and condition need to be considered in order to understand the status of cold-water species such as M. poutassou.

Angiostoma namekuji n. sp. (Nematoda: Angiostomatidae) from terrestrial slugs on Oshiba Island in the Seto Inland Sea, Japan

A new species of nematode, Angiostoma namekuji n. sp. (Angiostomatidae: Rhabditida), is described from the intestinal lumen of the terrestrial slug Philomycidae gen. sp. collected from Oshiba Island in the Seto Inland Sea, Hiroshima Prefecture, Japan. The new species is recognized by the following characteristics: body length 2,782-3,599 (mean 3,240) μm (male); 4,666-5,532 (5,030) μm (female); lateral field present; pharyngeal corpus with valves in the bulb; male with short tail, c = 35-57 (48), with one denticle; and seven pairs of genital papillae arranged as 1+2/3+1; female with tail having small denticles on distal tip; uterus c.50% of the body size; each ovary long, starting near vulva, not coiled, reflexed and reaching uterus; ovaries not crossing each other. Our phylogenetic tree based on sequences of the nuclear 28S ribosomal RNA gene supported the generic allocation of the new species in Angiostoma Dujardin, 1845.

Spinicauda sumatrana sp. nov. (Nematoda: Heterakidae) from Ludeking's Crested Dragon, Lophocalotes ludekingi (Agamidae), from the Bukit Barisan Range of Sumatra

Spinicauda sumatrana sp. nov. is described from the large intestine of Ludeking's Crested Dragon, Lophocalotes ludekingi (Agamidae) from the Bukit Barisan Range of Sumatra. The new species is assigned to Spinicauda based on the presence of off-set lips in both male and female and a ventrally directed sucker combined with the absence of caudal alae in males. It is the 17th species assigned to the genus and differs from all congeners in the combination of spicule length, presence of a gubernaculum, presence of a tail filament and fourteen pairs of caudal papillae.

Spermiogénèse et fonction du sac vaginal chez Ichthyocephalus anadenoboli n. sp. (Rhigonematidae ; Nematoda), parasite d'Anadenobolus politus (Porat) (Rhinocricidae ; Diplopoda) en Guadeloupe

Ichthyocephalus anadenoboli n. sp. ( Rhigonematidae ; Nematoda) from Anadenobolus politus ( Porat ) ( Rhinocricidae ; Diplopoda ) from Guadeloupe is described. The new species most closely resembles I. egleri since both sexes are of approximately the same size and the spicules are markedly unequal; it is distinguished in having a much longer right spicule, by the form of the extremity of the left spicule and by the presence of a vaginal sac opening into the vagina at its junction with the uteri. In addition certain aspects of spermiogenesis in the new species are studied. Maturation of spermatids occurs in two phases, one in the testis and seminal receptacle of males, the second in the vaginal sac in females. The second phase involves profound changes in form as well as nuclear transformation. It is suggested that the vaginal sac observed in certain species of Rhigonema as well as the " bourse copulatrice " of certain Tetrameres spp. and Maupasina weissi , like that of Ichthyocephalus anadenoboli , are specialized to accommodate the final stages of spermiogenesis.

Environmental influence on Pristionchus pacificus mouth form through different culture methods

Environmental cues can impact development to elicit distinct phenotypes in the adult. The consequences of phenotypic plasticity can have profound effects on morphology, life cycle, and behavior to increase the fitness of the organism. The molecular mechanisms governing these interactions are beginning to be elucidated in a few cases, such as social insects. Nevertheless, there is a paucity of systems that are amenable to rigorous experimentation, preventing both detailed mechanistic insight and the establishment of a generalizable conceptual framework. The mouth dimorphism of the model nematode Pristionchus pacificus offers the rare opportunity to examine the genetics, genomics, and epigenetics of environmental influence on developmental plasticity. Yet there are currently no easily tunable environmental factors that affect mouth-form ratios and are scalable to large cultures required for molecular biology. Here we present a suite of culture conditions to toggle the mouth-form phenotype of P. pacificus. The effects are reversible, do not require the costly or labor-intensive synthesis of chemicals, and proceed through the same pathways previously examined from forward genetic screens. Different species of Pristionchus exhibit different responses to culture conditions, demonstrating unique gene-environment interactions, and providing an opportunity to study environmental influence on a macroevolutionary scale.

Chapiniella variabilis (Nematoda) parasitizing Chelonoidis carbonarius and C. denticulatus (Testudinidae) in the state of Piauí

Chapiniella variabilis (Chapin, 1924), a strongylid nematode, was collected parasitizing the large intestine of the tortoises Chelonoidis carbonarius (Spix, 1824) (Cc) and C. denticulatus (Linnaeus, 1766) (Cd) in the Zoobotanical Park of the municipality of Teresina, state of Piauí, Brazil. The taxonomic identification was based on morphological and morphometric features, using bright-field and scanning electron microscopy. The present study adds new observations on the morphology, mainly relating to the mouth papillae, external and internal leaf-crown elements, excretory pore, deirids and male and female posterior end. The parasitic indices of prevalence (P), mean intensity (MI), mean abundance (MA) and range of infection (RI) of C. variabilis in these two tortoise species were: P = 100%, MI = 833.3, MA = 833.3, RI = 500-1,500 (Cc); P = 100%, MI = 472.2, MA = 472.2, RI = 333-500 (Cd). This record expands occurrences of C. variabilis to a new host, C. carbonarius, and to another state in Brazil, in the Neotropical region of South America. Adjustment to host management with the aim of improving hygiene and health conditions is suggested.

Morphological and morphometric features of nematode-cysts in Gymnotus inaequilabiatus liver in the Brazilian Pantanal

The aim of this study was to determine the morphometric measures and morphological aspects of nematode-cysts in Gymnotus inaequilabiatus, and the presence of melanomacrophage centers (MMCs) associated with the periphery of cysts and in the liver parenchyma. Adult specimens, 34 female (123.1 ± 43.9g) and 45 male (135.5 ± 43.4g), from Paraguay River, Corumbá, Brazil, were used. The number of nematode-cysts was determined in 79 livers and 25 of them randomly selected for histopathological analysis and morphometric measures of nematode-cysts (mean diameter, thickness of collagen layer, and cyst-wall layer). The percentage of cysts with MMCs on the periphery and density in the liver parenchyma was estimated. The average number of macroscopic cysts was of 48.7 ± 2.78. Granulomatous reaction was observed surrounding the cysts. Diameter, collagen layer and cyst-wall measurements were 293.0 ± 75.18 (µm), 17.72 ± 6.01 (µm) and 12.21 ± 9.51 (µm), respectively. The number of nematode-cysts was correlated with hepatosomatic index, (r=0.26, P<0.05). Collagen layer was correlated with cyst diameter (r=0.62, P<0.01). Pericystic and parenchymatous MMCs were moderately (r=0.48) and highly (r=0.90) correlated with nematode-cysts number. Morphological characteristics of hepatic tissue and cysts-nematodes measures suggest that G. inaequilabiatus acts as a paratenic host to nematodes in the larval stage.

Three new species of Pharygodonidae (Nematoda: Oxyuridea) in Laudakia tuberculata (Squamata: Agamidae) from Dehradun, Uttarakhand, India

Parapharyngodon tuberculata sp. nov., Thelandros tuberculata sp. nov. and Thelandros dehradunensis sp. nov. (Nematoda: Pharyngodonidae) from the large intestine of a rock lizard, Laudakia tuberculata Gray, 1827), are described and illustrated. Parapharyngodon tuberculata sp. nov. is the 8th Oriental species and 59th species assigned to the genus Parapharyngodon and differs from other species of the genus by possessing 3 pairs of caudal papillae, an echinate cloacal lip, 112-115 µm spicule length and postbulbar ovary. Thelandros tuberculata sp. nov. is the 5th and Thelandros dehradunensis sp. nov. the 6th Oriental species, respectively, and they are the 40th and 41st species assigned to the genus Thelandros. They differ from other species of the genus in caudal papillae arrangement, length of spicules, and structure of the anterior end of the esophagus. We transfer Parapharyngodon arequipensis Calisaya and Cordova, 1997 to Thelandros arequipensis (Calisaya and Cordova, 1997) comb. n. based upon the presence of a terminal operculum in the egg and large, pendant, caudal papillae.

Morphological re-description of Electrotaenia malapteruri (Cestoda: Proteocephalidae) and Dujardinnascaris malapteruri (Nematoda: Heterocheilidae) infecting the Electric catfish Malapterurus electricus and heavy metal accumulation in host and parasites in relation to water and sediment analysis in Lake Manzala, North Delta, Egypt

Parasites are one of the most serious limiting factors in aquaculture. The Electric catfish Malapterurus electricus was subjected to study the prevalence and mean intensity of parasitic infections throughout the whole year of 2015. Heavy metals accumulation in host fish and parasites were determined in relation to water quality and sediments of two different sites of Lake Manzala (Manzala and Bahr El-Baqar), Egypt. A total of 100 specimens of Electric catfish were collected and examined for the presence of helminth parasites. Two parasite species were recovered and morphologically identified. These were cestoda Electrotaenia malapteruri and nematode Dujardinnascaris malapteruri. Heavy metal analysis in water and sediments showed that measured heavy metals in Bahr El-Baqar were found in risky levels higher than permissible limits and Manzala site. Sediments were found to contain a higher level of metals than water samples. Heavy metals accumulation in recovered parasites and their host were also determined and showed significantly higher concentrations in parasites compared to their host tissues. According to bioconcentration factors, E. malapteruri showed that highest accumulation rate for all recorded elements up to 302. Essential elements like Cu and Fe were found in significantly higher concentrations in D. malapteruri, whereas E. malapteruri accumulated elements Cd, Pb, Ni, Mn, Zn and Ca to a significantly higher degree. Accordingly, the ratios (C[D.malapteruri]/C[E. malapteruri]) for most essential elements were higher than 0.5. Therefore, fish cestodes can be regarded as useful bio-indicators more than nematodes when evaluating the environmental pollution of aquatic ecosystems by heavy metals.

First record and description of juvenile stages of Longidorus artemisiae Rubtsova, Chizhov & Subbotin, 1999 (Nematoda: Longidoridae) in Poland and new data on L. juglandicola Lišková, Robbins & Brown, 1997 based on topotype specimens from Slovakia

This paper presents the first geographical record of the needle nematode Longidorus artemisiae Rubtsova, Chizhov & Subbotin, 1999 outside Russia. This species was found in Poland near the city of Skierniewice in association with nettle (Urtica dioica L.). Morphometric and morphological data are provided, including the first description of juveniles of this species. Nematodes of the Polish population differ from the type-population in Russia in possessing a thicker body (lower 'a' index) in both sexes; males having a longer body and longer spicules; different sex ratio (1:2 in Polish population vs 1:1 in the type-population) and somewhat less expanded lips. Molecularly, the Polish population was characterised by sequencing D2-D3 28S rDNA and ITS1 markers. Additionally, new data on these two markers are provided for another species, Longidorus juglandicola Lišková, Robbins & Brown, 1997, obtained from topotype specimens from Slovakia. Surprisingly, despite the high morphological similarity of these two species, analysis of their phylogenetic position did not show close phylogenetic relation and several other species (less similar in general morphology) appeared more closely related to both L. artemisiae and L. juglandicola.

Remarkable Diversity and Prevalence of Dagger Nematodes of the Genus Xiphinema Cobb, 1913 (Nematoda: Longidoridae) in Olives Revealed by Integrative Approaches

The genus Xiphinema includes a remarkable group of invertebrates of the phylum Nematoda comprising ectoparasitic animals of many wild and cultivated plants. Damage is caused by direct feeding on root cells and by vectoring nepoviruses that cause diseases on several crops. Precise identification of Xiphinema species is critical for launching appropriate control measures. We make available the first detailed information on the diversity and distribution of Xiphinema species infesting wild and cultivated olive in a wide-region in southern Spain that included 211 locations from which 453 sampling sites were analyzed. The present study identified thirty-two Xiphinema spp. in the rhizosphere of olive trees, ten species belonging to Xiphinema americanum-group, whereas twenty-two were attributed to Xiphinema non-americanum-group. These results increase our current knowledge on the biodiversity of Xiphinema species identified in olives and include the description of four new species (Xiphinema andalusiense sp. nov., Xiphinema celtiense sp. nov., Xiphinema iznajarense sp. nov., and Xiphinema mengibarense sp. nov.), and two new records for cultivate olives (X. cadavalense and X. conurum). We also found evidence of remarkable prevalence of Xiphinema spp. in olive trees, viz. 85.0% (385 out of 453 sampling sites), and they were widely distributed in both wild and cultivated olives, with 26 and 17 Xiphinema spp., respectively. Diversity indexes (Richness, Hill´s diversity, Hill´s reciprocal of D and Hill´s evenness) were significantly affected by olive type. We also developed a comparative morphological and morphometrical study together with molecular data from three nuclear ribosomal RNA genes (D2-D3 expansion segments of 28S, ITS1, and partial 18S). Molecular characterization and phylogenetic analyses allowed the delimitation and discrimination of four new species of the genus described herein and three known species. Phylogenetic analyses of Xiphinema spp. resulted in a general consensus of these species groups. This study is the most complete phylogenetic analysis for Xiphinema non-americanum-group species to date.

Nematode parasites infecting the starry batfish Halieutaea stellata (Vahl) (Lophiiformes: Ogcocephalidae) from the East and South China Sea

The starry batfish Halieutaea stellata (Vahl) is a small, benthic fish found in Indo-West Pacific Oceans. However, our present knowledge of the helminth parasites of this fish is still fragmentary. In this study, a total of 29 fish collected from the East and South China Sea were examined to determine the prevalence, intensity and species composition of helminth parasites in H. stellata. Using morphological and molecular approaches, four species of nematodes were found parasitic in this fish host, including the adults and fourth-stage larvae of Raphidascaroides nipponensis Yamaguti 1941; adults and third-stage larvae of Raphidascaris lophii (Wu 1949), third- and fourth-stage larvae of Hysterothylacium larval type IV-A of Shamsi, Gasser & Beveridge 2013 and third-stage larvae of Hysterothylacium amoyense (Hsü 1993). Halieutaea stellata represents a new host record for the three last-named nematodes. Raphidascaroides nipponensis with the highest prevalence (82.5%) and intensity (mean = 13.5) of infection was considered as the dominant parasite species in H. stellata. The detailed morphology of the different developmental stages of the four nematode species was studied using light and scanning electron microscopy. All nematode species were also genetically characterized by sequencing and analysing the internal transcribed spacer (ITS) of the ribosomal DNA. This study provides further data on the occurrence of nematode parasites in H. stellata and also contributes to facilitate an accurate and rapid diagnosis of the infection by these little-known nematodes.

[EXTERNAL QUALITY ASSESSMENT FOR THE LABORATORY IDENTIFICATION OF THE PATHOGENS OF PARASITIC DISEASES AS AN ELEMENT FOR IMPROVING THE POSTGRADUATE TRAINING OF SPECIALISTS]

Within the framework of the Federal External Quality Assessment (EQA) System and in the context of postgraduate training improvement for health workers in 2010-2014, specialists from the laboratories of the therapeutic-prophylactic organizations and institutions of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Welfare were examined for their professional competence in microscopically identifying the pathogens of parasitic diseases in feces. The virtual remote educational computer technology tools that included different combinations of 16 helminthic species, 5 intestinal protozoan species, and a number of artefacts, were used. The specialists from 984 laboratories of multidisciplinary therapeutic-prophylactic organizations and hygiene and epidemiology centers in all Federal Districts of the Russian Federation were covered. A total of 8245 replies were analyzed. The detection rate for helminths was 64.0%, including those by a taxonomic group (nematodes, 65.0%; cestodes, 72.0%; trematodes, 55.1%). There was a dynamic decrease in the above indicators. There were low detection rates for trematodes parasitizing the small intestine (Metagonimus, 10.2%; Nanophyetus, 26.2%) and hepatobiliary organs (Fasciola, 59.6%; Clonorchis, 34.9%). The similar trend was seen in the detection rates for the pathogens of geohelminthisms (ascariasis, trichocephaliasis, etc.) and contagious helminthisms (enterobiasis, hymenolepiasis). The level of competence in detecting and identifying intestinal protozoa was much lower than the similar rates for helminthism pathogens. EQA for the laboratory diagnosis of the pathogens of parasitic diseases, by using the virtual tools is a leading element of the postgraduate training system for laboratory specialists. The results of EQA for the laboratory diagnosis of the pathogens of parasitic diseases are a basic material for the development, and improvement of training modernization programs, by applying a modular approach.

Description of a new species of Chabaudus Inglis and Ogden, 1965 (Nematoda: Seuratoidea) from the frog Euphlyctis cyanophlyctis from Dehrandun, Uttarakhand, India

Chabaudus dehradunensis sp. nov. (Nematoda: Seuratoidea) from the large intestine of the water skipper, Euphlyctis cyanophlyctis (Anura, Dicroglossidae), from Dehrandun, India is described and illustrated. Chabaudus dehradunensis sp. nov. is the 6th species assigned to the genus and 1st species reported from India. It is separated from its congeners based upon the number and arrangement of caudal papillae and the length of spicule. Euphlyctis cyanophlyctis is the new host record for the genus Chabaudus.

First report of Schulzia travassosi (Nematoda, Trichostrongylina, Molineoidea) for amphibians of the Chaco region in Argentina and proposal of Oswaldocruzia melanostictusi nov. comb

This is the first record of the nematode parasite Schulzia travassosi (Trichostrongylina, Molineidae) in two Argentinean amphibians, Leptodactylus bufonius and Rhinella major, collected in two localities of the Chaco region, Las Lomitas (Formosa Province) and Taco Pozo (Chaco Province). The species was observed using light and scanning electron microscopy (SEM) and compared with previous studies of Paraguayan specimens. Regarding metric characters, the measurements found in Argentinean specimens generally did not differ from those of Paraguayan specimens; some differences were observed in the total length of males and females (some longer and some shorter than Paraguayan specimens), length of the oesophagus (in almost all specimens shorter than in Paraguayan ones) and position of the vulva (nearer to posterior end in Argentinean specimens). The branches and sphincter of ovejector are slightly longer than in Paraguayan female specimens. In males, ray 4 is almost the same length as rays 2, 3 and 5, 6. Cephalic end, cephalic vesicle, synlophe and vulvar depression were viewed under SEM. Schulzia melanostictusi Chopra, Shing and Kumar, 1986 is reassigned as Oswaldocruzia melanostictusi (Chopra, Shing and Kumar, 1986) nov. comb.

Squamasnema amazonica n. gen. n. sp. (Heligmonellinae): A new parasite of Proechimys roberti (Rodentia: Echimyidae) in the Brazilian Amazon

A new species of nematode, Squamasnema amazonica n. gen. n. sp., is described based on specimens found parasitizing the small intestine of Proechimys roberti (Rodentia: Echimyidae) collected during a survey of the fauna of Tapirapé-Aquirí National Forest (Brazil, Eastern Brazilian Amazon). The nematodes were fixed and processed for light microscopy and scanning electron microscopy (SEM). These nematodes were classified under the family Heligmonellidae and the subfamily Heligmonellinae. Although several species in the family Heligmonellidae exhibit discontinuous ridges, Squamasnema n. gen. and Trichotravassosia are the only genera with columns of scales along their entire body, as an apomorphy of the synlophe. Squamasnema n. gen. has columns of cuticular cells along its body, except for on the left flank, and exhibits a synlophe with no size gradient or inclination and does not present chitinized structures supporting the synlophe. Therefore, due to these morphological differences of Squamasnema n. gen., the creation of a new genus was necessary.

[VARIABILITY AND DETERMINING FACTORS OF THE BODY SIZE STRUCTURE OF THE INFRAPOPULATION OF COSMOCERCA ORNATA (NEMATODA: COSMOCERCIDAE) IN MARSH FROGS]

Variability of the body size in females of the Cosmocerca ornata (Dujardin, 1845), a parasite of marsh frogs, is studied. The influence of both biotic (age, sex and a phenotype of the host, density of the parasite population) and abiotic (a season of the year, water temperature) factors on the formation of the body size structure in the C. ornata hemipopulation (infrapopulation) is demonstrated. The body size structure of the C. ornata hemipopulation is characterized by the low level of individual variability as within certain subpopulation groups of amphibians (sex, age and phenotype), so within the population of marsh frogs as a whole. The more distinct are the differences in biology and ecology of these host subpopulations, the more pronounced is the variability in the body size of C ornata.

Soil properties and olive cultivar determine the structure and diversity of plant-parasitic nematode communities infesting olive orchards soils in southern Spain

This work has studied for the first time the structure and diversity of plant-parasitic nematodes (PPNs) infesting olive orchard soils in a wide-region in Spain that included 92 locations. It aims at determining which agronomical or environmental factors associated to the olive orchards are the main drivers of the PPNs community structure and diversity. Classical morphological and morphometric identification methods were used to determine the frequency and densities of PPNs. Thirteen families, 34 genera and 77 species of PPNs were identified. The highest diversity was found in Helicotylenchus genus, with six species previously reported in Spain and with H. oleae being a first report. Neodolichorhynchus microphasmis and Diptenchus sp., Diphtherophora sp., and Discotylenchus sp., usually considered fungal feeders, were also reported for the first time associated to olive rhizosphere. PPNs abundance ranged from 66 to 16,288 individuals/500-cm3 of soil with Helicotylenchus digonicus being the most prevalent species, followed by Filenchus sp., Merlinius brevidens and Xiphinema pachtaicum. Nematode abundance and diversity indexes were influenced by olive cultivar, and orchard and soil management practices; while olive variety and soil texture were the main factors driving PPN community composition. Soil physicochemical properties and climatic characteristics most strongly associated to the PPN community composition included pH, sand content and exchangeable K, and maximum and minimum average temperature of the sampled locations. Our data suggests that there is a high diversity of PPNs associated to olive in Southern Spain that can exert different damage to olive roots depending on the olive variety and their abundance. Further analysis to determine the resistance levels of most common olive varieties to the prevalent PPNs in Spain will help to choose the most appropriate ones for the establishment of new plantations. This choice will take into consideration the specific soils and environments where those olive varieties will be established.

The relationships of marsupial-dwelling Viannaiidae and description of Travassostrongylus scheibelorum sp. n. (Trichostrongylina: Heligmosomoidea) from mouse opossums (Didelphidae) from French Guiana

The trichostrongylid nematode Travassostrongylus scheibelorum sp. n. from the Linnaeus' mouse opossum, Marmosa murina (Linnaeus) (type host), and the woolly mouse opossum, Marmosa demerarae (Thomas), from French Guiana is described. The nematodes have a synlophe with ridges frontally oriented from right to left, six dorsal and six ventral, at midbody; seven dorsal and seven ventral posterior to the vulva, and two cuticular thickenings within the lateral spaces; a long dorsal ray and a pointed cuticular flap covering the vulva. This is the 12th species of Travassostrongylus Orloff, 1933, which includes species featuring ridges around the synlophe and a didelphic condition. These traits contrast with those in other genera in the Viannaiidae Neveu-Lemaire, 1934, which feature ventral ridges on the synlophe of adults and a monodelphic condition. Members of the family are chiefly Neotropical and are diagnosed based on the presence of a bursa of the type 2-2-1, 2-1-2 or irregular, and cuticle without ridges on the dorsal side (at least during one stage of their development). Herein, we present a reconstruction of the ancestral states of the didelphic/monodelphic condition and the cuticular ridges that form the synlophe in opossum-dwelling trichostrongyles, namely Travassostrongylus and Viannaia Travassos, 1914. Our investigations suggest they are not reciprocal sister taxa and that the change from didelphy to monodelphy and the loss of dorsal ridges, occurred in the common ancestor of species of Viannaia. These results suggest a synlophe with three ventral ridges is not plesiomorphic in the opossum dwelling trichostrongylids.

Huffmanela hamo sp. n. (Nematoda: Trichosomoididae: Huffmanelinae) from the dagger-tooth pike conger Muraenesox cinereus off Japan

Huffmanela hamo sp. n. is described from eggs only, which were found in black spots in the somatic musculature of a dagger-tooth pike conger, Muraenesox cinereus (Forsskål), caught off Japan. The eggs are 66-77 microm (mean 72 microm) in length and 33-38 microm (mean 35 microm) in width. The surface of the eggs is smooth and bears neither envelope nor filaments. The species is distinguished from other members of the genus by the dimensions of its eggs and the characteristics of their surface. This is the first species of Huffmanela Moravec, 1987 to be described from an anguilliform fish, and the twentieth nominal species in the genus. Similar black spots with eggs were reported four times in ten years from this fish caught off Japan; although eggs could not be examined, it is likely that the same species was involved in all cases.

New plant-parasitic nematode from the mostly mycophagous genus Bursaphelenchus discovered inside figs in Japan

A new nematode species, Bursaphelenchus sycophilus n. sp. is described. The species was found in syconia of a fig species, Ficus variegata during a field survey of fig-associated nematodes in Japan. Because it has a well-developed stylet and pharyngeal glands, the species is considered an obligate plant parasite, and is easily distinguished from all other fungal-feeding species in the genus based upon these characters. Although B. sycophilus n. sp. shares an important typological character, male spicule possessing a strongly recurved condylus, with the “B. eremus group” and the “B. leoni group” of the genus, it was inferred to be monophyletic with the “B. fungivorus group”. The uniquely shaped stylet and well-developed pharyngeal glands is reminiscent of the fig-floret parasitic but paraphyletic assemblage of “Schistonchus”. Thus, these morphological characters appear to be an extreme example of convergent evolution in the nematode family, Aphelenchoididae, inside figs. Other characters shared by the new species and its close relatives, i.e., lack of ventral P1 male genital papilla, female vulval flap, and papilla-shaped P4 genital papillae in males, corroborate the molecular phylogenetic inference. The unique biological character of obligate plant parasitism and highly derived appearance of the ingestive organs of Bursaphelenchus sycophilus n. sp. expands our knowledge of the potential morphological, physiological and developmental plasticity of the genus Bursaphelenchus.

Cryopreservation of roe deer abomasal nematodes for morphological identification

Conventional methods to preserve adult nematodes for taxonomic purposes involve the use of fixative or clearing solutions (alcohol, formaldehyde, AFA and lactophenol), which cause morphological alterations and are toxic. The aim of this study is to propose an alternative method based on glycerol-cryopreservation of nematodes for their subsequent identification. Adults of trichostrongylid nematodes from the abomasum of roe deer (Capreolus capreolus Linnaeus) were glycerol-cryopreserved and compared with those fixed in formaldehyde, fresh and frozen without cryoprotectans. Morphology, transparency and elasticity of the anterior and posterior portion of male nematodes were compared, especially the caudal cuticular bursa and genital accessories. The method presented is quick and easy to use, and the quality of nematode specimens is better than that of nematodes fixed by previously used fixatives. Moreover, glycerol cryopreserved nematodes can be stored for a long time at -20 degrees C in perfect condition and they could be suitable for further analyses, such as histological or ultrastructural examinations.

WormSizer: high-throughput analysis of nematode size and shape

The fundamental phenotypes of growth rate, size and morphology are the result of complex interactions between genotype and environment. We developed a high-throughput software application, WormSizer, which computes size and shape of nematodes from brightfield images. Existing methods for estimating volume either coarsely model the nematode as a cylinder or assume the worm shape or opacity is invariant. Our estimate is more robust to changes in morphology or optical density as it only assumes radial symmetry. This open source software is written as a plugin for the well-known image-processing framework Fiji/ImageJ. It may therefore be extended easily. We evaluated the technical performance of this framework, and we used it to analyze growth and shape of several canonical Caenorhabditis elegans mutants in a developmental time series. We confirm quantitatively that a Dumpy (Dpy) mutant is short and fat and that a Long (Lon) mutant is long and thin. We show that daf-2 insulin-like receptor mutants are larger than wild-type upon hatching but grow slow, and WormSizer can distinguish dauer larvae from normal larvae. We also show that a Small (Sma) mutant is actually smaller than wild-type at all stages of larval development. WormSizer works with Uncoordinated (Unc) and Roller (Rol) mutants as well, indicating that it can be used with mutants despite behavioral phenotypes. We used our complete data set to perform a power analysis, giving users a sense of how many images are needed to detect different effect sizes. Our analysis confirms and extends on existing phenotypic characterization of well-characterized mutants, demonstrating the utility and robustness of WormSizer.

Morphometrical and ecological analysis of nematodes of the family Capillariidae (Neveu-Lemaire, 1936) in wild ducks (Anatinae) from the north-western Poland

West Pomerania is located on the migratory route of many species of birds. Among them are many representatives of wild duck species (subfamily Anatinae), which are often the primary hosts of many helminths due to the fact of living in two different environments: terrestrial and aquatic. However, until the end of the 90s, research conducted in Poland on the helminth fauna of wild birds, including nematodes of the family Capillariidae, did not include the north-western region of the country. These first studies performed in 1999, aimed at the identification of the nematodes of wild ducks from the West Pomerania region, revealed the presence of three species belonging to family Capillariidae, i.e. Capillaria anatis (Schrank, 1790) Travassos, 1915, Eucoleus contortus (Creplin, 1839) Gagarin, 1951 and Pseudocapillaria mergi (Madsen, 1945). The purpose of the current study was to perform a comprehensive ecological analysis of C. anatis, E. contortus and P. mergi, including such factors as intensity, prevalence, relative density, index of fidelity and dominance index. The experimental material comprised 811 nematodes isolated from the gastrointestinal tracts of 953 ducks. These 9 species of ducks belong to three different tribes of the Anatinae subfamily: Anatini (Anas clypeata, A. crecca, A. platyrhynchos), Aythyini (Aythya fuligula, A. marila) and Mergini (Bucephala clangula, Clangula hyemalis, Mergus merganseri, Somateria mollissima) and diverse in terms of their biology and ecology. The morphometric and morphological analyses fail to identify any significant differences in the body structures of nematodes of the species C. anatis, E. contortus and P. mergi of the West Pomerania region in comparison with those found in other regions of Poland and Europe. The ecological analysis of the Capillariidae family in the West Pomerania region revealed that ducks of the tribe Anatini (mainly A. platyrhynchos) are the most common hosts of E. contortus species, C. anatis is most commonly found in ducks of the tribe Aythyini, and P. mergi is relatively frequent in ducks of the tribe Mergini (mainly in M. merganser).

A new species of Halaphanolaimus (Nematoda: Leptolaimidae) from the southern Black Sea (Turkey) with a modified key for species identification

Halaphanolaimus sergeevae n. sp. is described and illustrated from the Sinop coasts (southern Black Sea, Turkey). The new species morphologically resembles H. pellucidus Southern, 1914, but differs from it by having a higher number of tubular supplements (12-14 vs. 6-7), longer spicules (68-70 im vs 47-52 [tm), smaller tail/spicule ratio (1.6 vs. 2.7), smaller body size (926-1273 vs. 1500 microm), and smaller De Man indices of a, b and c'. An updated identification key to the species of Halaphanolainius is proposed.

Studies on the genus Aporcelaimellus Heyns, 1965 (Nematoda, Dorylaimida, Aporcelaimidae). Four atypical species with simple uterus from Southern Iberian Peninsula

Three new and one known species of the genus Aporcelaimellus, collected mainly in natural areas from the Iberian Peninsula and characterized by having a simple uterus and atypical caudal region are described and illustrated, including line drawings, LM pictures and/or SEM pictures. Aporcelaimellus deserticola sp. n. is distinguished by its body 1.79-2.43 mm long, lip region 14-16 pm broad and offset by expansion rather than by constriction, odontostyle 18-21 µm long, neck 464-555 µm long, pharyngeal expansion 234-283 µm long or 49-52% of total neck length, a dorsal cell mass present at level of anterior end of intestine, uterus 34-67 µm long or 0.6-1.1 times the corresponding body diameter, V= 49-55, tail conical with rounded terminus (29-43 µm, c = 47-66, c' = 0.9-1.4) and bearing a short but perceptible hyaline portion, and male unknown. Aporcelaimellus hyalinus sp. n. is characterized by its body 1.49-2.23 mm long, lip region offset by constriction and 13-16 µm broad, odontostyle 14-16 µm long, neck 389-474 µm long, pharyngeal expansion 183-242 µm long or 45-53% of total neck length, uterus 44-106 µm long or 0.7-1.8 times the corresponding body diameter, V = 48-55, tail conical with rounded terminus (27-41 µm, c = 38-68, c' = 1.0-1.4) and short inner core, spicules 56 µm long, and seven irregularly spaced ventromedian supplements. Aporcelaimellus rarus sp. n. is distinguished by its body 1.96-2.34 mm long, lip region offset by constriction and 14-16 µm broad, odontostyle 15-16 µm long, neck 411-518 µm long, pharyngeal expansion 196-270 µm long or 48-52% of total neck length, a dorsal cellular mass at a short distance behind the cardia, uterus 63-96 µm long or 0.8-1.5 times the corresponding body diameter, V= 51-56, female tail short and conical (28-40 µm, c = 50-74, c' = 0.7-0.9) with rounded terminus and bearing a dorsal concavity at its posterior half, and males unknown. New data are provided for A. salicinus. A discussion of these atypical species is also provided.

Multi-decadal survival of an Antarctic nematode, Plectus murrayi, in a -20°C stored moss sample

It is not clear for how long Antarctic soil nematodes might tolerate freezing. Samples of the Antarctic moss, Bryum argenteum, were collected on 1 October 1983 at Langhovde, Soya coast, eastern Antarctica and were stored at -20°C. After 25.5 years of storage, living nematodes were recovered from the samples and were identified as Plectus murrayi by morphological examination and nucleotide sequencing of ribosomal RNA loci. The nematodes can grow and reproduce in a water agar plate with bacteria (mainly Pseudomonas sp.) cultured from the moss extract. They showed freezing tolerance at -20°C and -80°C and their survival rate after exposure to -20°C, but not -80°C, was increased if they were initially frozen slowly at a high sub-zero temperature. They also showed some ability to tolerate desiccation stress.

Exposure to mercury causes formation of male-specific structural deficits by inducing oxidative damage in nematodes

Metal exposure causes reproductive damage in hermaphrodite nematodes, but effects of metals on male development are unclear. We here investigated the effects of mercury chloride exposure on development of males. Hg exposure severely increased the percentage of abnormal males, disrupted the development of male-specific structures, and caused high reactive oxygen species (ROS) production in male tails. Pre-treatment with antioxidant (vitamin E) protected the nematodes against toxicity from Hg exposure on development of male-specific structures. The ROS production in tails was closely correlated with formation of abnormal male-specific structures in males induced by Hg exposure. Moreover, mutations of clk-1, encoding ortholog of COQ7/CAT5, and daf-2, encoding an insulin/IGF receptor, functioned in two different pathways to suppress the formation of deficits in development of male-specific structures. Thus, three different lines of evidence support our conclusion that HgCl(2) causes male structure-specific teratogenesis via production of oxidative stress.

Goezia nankingensis Hsü, 1933 (Nematoda: Raphidascarididae) from the critically endangered Chinese paddlefish Psephurus gladius (Martens) (Acipenseriformes: Polyodontidae)

Goeziine nematodes identified as Goezia nankingensis Hsü, 1933 were collected from the Chinese paddlefish Psephurus gladius (Martens) (Acipenseriformes: Polyodontidae), a critically endangered freshwater fish, from the Yangtze River in China. Their examination, using light microscopy and, for the first time, scanning electron microscopy, revealed some erroneous and previously unreported morphological features, necessitating the redescription of this poorly known species. Goezia nankingensis is easily distinguished from its congeners by the morphology and arrangement of its cuticular spines, the short intestinal caecum and long ventricular appendix (ratio of intestinal caecum to ventricular appendix 1:10.0-18.3), the short spicules (0.34-0.49 mm long, representing 6.09-10.1% of the body length), the number and arrangement of male caudal papillae [14-16 pairs in total, approximately arranged: precloacal 7-10 pairs, paracloacal 2 pairs and postcloacal 4-6 pairs (one pair double)], and the presence of a particular medio-ventral, precloacal papilla in the male.

Contracaecumovale (Nematoda: Anisakidae) from Rollandia rolland Quoy & Gaimard 1824 (Aves, Podicipedidae) in Argentina

Necropsy on 15 specimens of white-tufted grebe, Rollandiarolland, caught in the Mar Chiquita and Chascomús lagoons (Buenos Aires province), revealed the presence of Contracaecumovale (Linstow, 1907). This nematode shows a marked specificity for podicipediform birds. The specimens were identified from morphological study on features such as cephalic and esophageal structures and caudal papillae, using both optical and scanning electron microscopy. This is the first record of C. ovale parasitizing R. rolland in Argentina.

Parasites of captive fallow deer (Dama dama L.) from southern Poland with special emphasis on Ashworthius sidemi

Fallow deer in Poland is an alien species, with an ambiguous legal status. It is considered both, a game and a farm animal, which introductions in recent years led to a substantial increase of its population. As a representative of cervids, it shares with other free-ranging and domestic ruminants many of gastrointestinal helminths, among them an alien Ashworthius sidemi, the nematode of a high pathogenicity. Until now, the parasite was observed in Poland at two foci of the wild (i.e., Bialowieza and Bieszczady forests), but not yet in fallow deer. The present study was intended to recognize the infection level, and helminth species composition, in fallow deer living in captivity. Alimentary tracts of four animals, hunted in enclosure situated in Dulowa Primeval Forest, were dissected. Nematodes belonging to seven species: Spiculopteragia spiculoptera, S. mathevossiani, S. asymmetrica, Nematodirus filicollis, Aonchotheca bovis, Oesophagostomum radiatum and Ashworthius sidemi were recovered, with the latest helminth being predominat. In the present study, the origin of A. sidemi infection, its impact on the host and abomasum nematode communities, as well as the potential parasite spread on other ruminants, were investigated.

[Variability of the dimensional structure in the hemipopulation of Thominx neopulchra (Nematoda: Capillariidae) females from bats of the genus myotis (Chiroptera: Vespertilionidae)]

Variability of the dimensional structure in the hemipopulation Thominx neopulchra females from 3 species of the genus Myotis bats in the Zhiguli State Reserve was examined. The size of T. neopulchra from different bat species varied within the limits constituting 10.17-13.41 mm. It was demonstrated that the variability of the dimensional structure in the subpopulation group T. neopulchra from Daubenton's bats did not depend on the number of parasites in the host and the season and is probably determined by the genetic polymorphism of the parasite population.

Sensory neuroanatomy of Parastrongyloides trichosuri, a nematode parasite of mammals: Amphidial neurons of the first-stage larva

Owing to its ability to switch between free-living and parasitic modes of development, Parastrongyloides trichosuri represents a valuable model with which to study the evolution of parasitism among the nematodes, especially aspects pertaining to morphogenesis of infective third-stage larvae. In the free-living nematode Caenorhabditis elegans, developmental fates of third-stage larvae are determined in part by environmental cues received by chemosensory neurons in the amphidial sensillae. As a basis for comparative study, we have described the neuroanatomy of the amphidial sensillae of P. trichosuri. By using computational methods, we incorporated serial electron micrographs into a three-dimensional reconstruction of the amphidial neurons of this parasite. Each amphid is innervated by 13 neurons, and the dendritic processes of 10 of these extend nearly to the amphidial pore. Dendritic processes of two specialized neurons leave the amphidial channel and terminate within invaginations of the sheath cell. One of these is similar to the finger cell of C. elegans, terminating in digitiform projections. The other projects a single cilium into the sheath cell. The dendritic process of a third specialized neuron terminates within the tight junction of the amphid. Each amphidial neuron was traced from the tip of its dendrite(s) to its cell body in the lateral ganglion. Positions of these cell bodies approximate those of morphologically similar amphidial neurons in Caenorhabditis elegans, so the standard nomenclature for amphidial neurons in C. elegans was adopted. A map of cell bodies within the lateral ganglion of P. trichosuri was prepared to facilitate functional study of these neurons.

Angiostoma margaretae n. sp (Nematoda: Angiostomatidae), a parasite of the milacid slug Milax gagates Draparnaud collected near Caledon, South Africa

Angiostoma margaretae n. sp. (Angiostomatidae) is described from the oesophagus of the slug Milax gagates Draparnaud collected near Caledon in the Western Cape Province of South Africa. The new species closely resembles another parasite of a milacid slug, A. milacis Ivanova & Wilson, 2009, with a similar head, stoma and spicule shape, the presence of distally outstretched ovaries, coiled oviducts, the same number of caudal papillae and enlarged rectal glands. However, A. margaretae differs from the latter by having: a shorter, wider tail with a rounded vs pointed tip; the distal parts of both ovaries with a particular hook-like shape due to an expansion closely following the short initial zone; ovoviparous females; and a different arrangement of male papillae. A. margaretae is comparable with A. limacis Dujardin, 1845, A. asamati (Spiridonov, 1985), A. coloaense (Pham Van Luc, Spiridonov & Wilson, 2005) and A. stammeri (Mengert, 1953), which have a similar stoma shape and size, but can be readily differentiated by the presence of distally outstretched vs reflexed ovaries and the presence vs lack of enlarged rectal glands. The new species has a similar arrangement of the ovaries to A. kimmeriense Korol & Spiridonov, 1991 and A. zonitidis Ivanova & Wilson, 2009, but is clearly differentiated by the lack of an off-set lip region and presence of a large bowl-shaped vs tubular stoma and less numerous male caudal papillae (seven pairs vs nine in A. kimmeriense and 10 in A. zonitidis).