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

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

A New Species of Cosmocercoides (Ascaridida: Cosmocercidae) Parasitic in Tree Frogs from Southern Amazonia.

Cosmocercoides meridionalis n. sp. is described from the large and small intestines of 5 species of tree frogs belonging to the families Hylidae and Phyllomedusidae collected from 2 localities in Southern Amazonia. The new species is allocated to the genus Cosmocercoides Wilkie, 1930, due to the presence of papillae in rosettes, which are complex caudal papillae surrounded by punctuations. Cosmocercoides meridionalis n. sp. differs from its congeners by a combination of the following characters: the absence of the gubernaculum, the total length of the female (twice the size of the male), and the presence of 26 rosette papillae with a unique arrangement and distribution pattern: 11 pre-cloacal pairs, 1 ad-cloacal pair, and 1 post-cloacal pair. This is the first species of the genus described from the Amazonia region.

A new species of Cruzia (Ascaridida; Kathlanidae) parasitizing Salvator merianae (Squamata, Teiidae) from the Atlantic forest in Brazil.

Cruzia lauroi sp. nov. is described from Salvator merianae (Duméril & Bibron, 1839) (Squamata; Teiidae). The new species differs from all previously described species through several morphological characteristics: number of tooth like structures per row in the inner pharynx; and presence of unpaired papillae on the anterior border of the cloacal aperture. However, Cruzia lauroi sp. nov. is closest to C. tentaculata (Rudolphi, 1819), through having similar distribution of male caudal papillae, unpaired pre-cloacal papillae and females with an pre-equatorial vulva. Cruzia lauroi sp. nov. differs from C. tentaculata regarding smaller total body length of individuals, higher number of tooth like structures per row in the pharynx, greater size of diverticulum, smaller size of spicules and a more anterior vulva than in C. tentaculata; and the males do not have caudal alae. Cruzia mazza, C. travassosia, C. mexicana and C. testudines were considered to be species inquirendae, because their descriptions need more detailed taxonomic studies.

Lagochilascaris minor (Nematoda, Ascarididae) in a domestic cat in a coastal city of the state of São Paulo.

This paper describes the discovery of Lagochilascaris minor parasitizing a stray cat (Felis catus) in São Sebastião, a coastal city in the state of São Paulo, Brazil. The cat presented fistulas with purulent secretion in the ventral cervical region. A thorough evaluation revealed nematodes in the site. The parasites were removed, amounting to a total of about 100 specimens. The parasite species was identified based on measurements and morphological characteristics of adult worms. This report of parasitism by L. minor in domestic cats in the state of São Paulo reinforces the need for greater attention to this parasitosis, given the increase in cases among carnivores in Brazil.

Prevalence of Heterakis Infection in Parental Flocks of Geese.

The prevalence of Heterakis infection in reproductive geese from 56 flocks was investigated between February 2015 and November 2019 by using both anatomopathologic and coproscopic examinations. The nematodes were microscopically examined, and 37.5% (21/56) of the flocks were infected with Heterakis nematodes, mostly with Heterakis dispar (35.7%). In one particular flock, a Heterakis gallinarum infection was noted. In two flocks, Heterakis infection was identified only during coproscopic examination. The infection susceptibility of the geese depended on the bird's age-in the first reproductive season, 50% of the flocks were positive; in the second season, 42% were positive; and in the third season, 30% were positive. The number of nematodes in each necropsied goose varied from 8 to 216 individuals. During the 5 years of epidemiologic analysis, the infection occurrence decreased from 66.7% to 11%.

Distribution of Four Parasitic Helminth Species in One Pen-Free, Egg-Laying Housing Facility, and the Corresponding Efficacy of Nutraceutical and Pharmaceutical Administrations.

In the spring of 2019, adult (75 wk old) brown laying hens from a commercial, pen-free, egg-laying facility (11,000 birds per house) located in northwest Arkansas were obtained for the purposes of sourcing robust and evenly dispersed cestode infections for anticipated anthelmintic evaluations. To that end, four birds from each of six discrete sites (northwest, northcentral, northeast, southwest, southcentral, and southeast) in one production barn were obtained on two occasions, 8 days apart, and necropsied for helminth counts. A definite, repeated, location-to-location variation in infection incidence and magnitude was seen for each of the two cestode parasite species present and for one of the two nematode parasite species present. Burdens of Ascaridia galli were generally similar regardless of bird location, with site-specific mean totals per bird over both sampling days between 31 and 80. For the remaining helminths, infections were greatest for birds from the southern half of the building as opposed to the northern and from the western end of the barn as opposed to the central or eastern portions. Location-specific mean worm burdens over both sample dates ranged from 340 to 1133 (Heterakis gallinarum), 14 to 277 (Raillietina cesticillus), and 1 to 35 (Choanotaenia infundibulum). The greatest individual bird infections were 299 (A. galli), 3575 (H. gallinarum), 1015 (R. cesticillus), and 102 (C. infundibulum). The above counts are for all developmental stages combined (A. galli and H. gallinarum) and for scolexes only (R. cesticillus and C. infundibulum), as determined via standard collection and quantification procedures using both intestinal contents and overnight soaks. Immediately before the mapping study outlined above, birds were obtained from the east end of the source barn and used for the nematocidal evaluation of fenbendazole in the water (5 mg/kg body weight [BW] for 1 day), levamisole in the water (8 mg/kg BW for each of 2 days), herbal mixture in the feed (1 gm/4.5 kg BW each day for 5 days), diatomaceous earth (2% of total feed for 10 days), and a nutraceutical mixture feed supplement (2% of feed for 7 days). Based on arithmetic means for adult forms, control trial efficacies for A. galli and H. gallinarum were 0% and 12% for the nutraceutical feed additive, 0% and 22% for the diatomaceous earth feed additive, 0% and 26% for dietary herbals, 87% and 63% for levamisole, and 82% and 84% for fenbendazole, respectively. Only adult burdens of A. galli and H. gallinarum for fenbendazole- and levamisole-treated birds were significantly different from control bird levels (P ≤ 0.05).

A new species of Cruzia (Ascaridida; Kathlanidae) parasitizing Salvator merianae (Squamata, Teiidae) from the Atlantic forest in Brazil / Uma nova espécie de Cruzia (Ascaridida; Kathlanidae) parasitando Salvator merianae (Squamata, Teiidae) de Mata Atlântica no Brasil

Abstract Cruzia lauroi sp. nov. is described from Salvator merianae (Duméril & Bibron, 1839) (Squamata; Teiidae). The new species differs from all previously described species through several morphological characteristics: number of tooth like structures per row in the inner pharynx; and presence of unpaired papillae on the anterior border of the cloacal aperture. However, Cruzia lauroi sp. nov. is closest to C. tentaculata (Rudolphi, 1819), through having similar distribution of male caudal papillae, unpaired pre-cloacal papillae and females with an pre-equatorial vulva. Cruzia lauroi sp. nov. differs from C. tentaculata regarding smaller total body length of individuals, higher number of tooth like structures per row in the pharynx, greater size of diverticulum, smaller size of spicules and a more anterior vulva than in C. tentaculata; and the males do not have caudal alae. Cruzia mazza, C. travassosia, C. mexicana and C. testudines were considered to be species inquirendae, because their descriptions need more detailed taxonomic studies.

Resumo Cruzia lauroi sp. nov. é uma nova espécie descrita em Salvator merianae (Duméril & Bibron, 1839) (Squamata; Teiidae). Essa nova espécie difere de todas as espécies descritas anteriormente por diferentes características morfológicas: pelo número de dentes por coluna longitudinal interna na faringe; pela presença de papila ímpar na borda anterior da cloaca. Entretanto, Cruzia lauroi sp. nov. possui similaridades com C. tentaculata (Rudolphi, 1819), por ter distribuição semelhante das papilas caudais dos machos, por possuir papila pré-cloacal ímpar e por possuir fêmeas com vulva pré-equatorial. Cruzia lauroi sp. nov. se difere de C. tentaculata em relação ao menor comprimento total do corpo dos indivíduos, pelo maior número de dentes por coluna longitudinal interna na faringe; pelo maior tamanho de divertículo; pelo menor tamanho de espículos; por possuir fêmeas com vulva mais próxima a extremidade anterior do que observado em fêmeas de C. tentaculata; e pelos machos não possuírem asa caudal. Cruzia mazza, C. travassosia, C. mexicana e C. testudines foram consideradas species inquirendae, pelo fato de suas descrições necessitarem de maior detalhamento taxonômico.

A new Cosmocercoides species (Ascaridida: Cosmocercidae), C. wuyiensis n. sp., from the Asiatic frog Amolops wuyiensis (Amphibia: Anura).

We identified and characterized a new cosmocercid nematode species, Cosmocercoides wuyiensis n. sp., through microscopic examination and sequencing of the partial small ribosomal RNA gene (18S rDNA), internal transcribed spacer (ITS) and mitochondrial cytochrome c oxidase subunit 1 (COI) genes. The new species was isolated from the intestine of the Asiatic frog Amolops wuyiensis Liu and Hu, 1975 captured from four localities of the Anhui province in south-east China. Among the 25 recorded species of the Cosmocercoides genus, the morphology of C. wuyiensis n. sp. is closest to that of C. kiliwai and C. malayensis, which were isolated from various Mexican frog and Malaysian lizard species, respectively. However, C. wuyiensis n. sp. displayed several distinguishing features, such as small size of the male body, two spicules of unequal lengths in the male, small gubernaculum, pre-, ad- and post-cloacal caudal rosette papillae in the ratio of 18-24:2:6 and simple papillae in the ratio of 14:multiple:4, circle and number of punctation in each rosette at 1:11-16, sharply conical tail-end and the presence of lateral alae and somatic papillae in both sexes. BLAST and the phylogenetic analyses of the 18S rDNA and ITS sequences indicated that C. wuyiensis n. sp. belonged to the genus Cosmocercoides, while that of the COI gene sequence of C. wuyiensis n. sp. showed 16.36% nucleotide divergence with C. pulcher and 47.99% nucleotide divergence with C. qingtianensis. The morphological and molecular characterization of C. wuyiensis n. sp. provides new taxonomic data for this genus.

Morphological and Genetic Characterization of the Poorly Known Species Subulura chinensis Schwartz, 1926 (Nematoda: Ascaridida) from Athene noctua (Scopoli) (Strigiformes: Strigidae).

INTRODUCTION: Subulura chinensis Schwartz, 1926 is a hitherto poorly known nematode species. The morphology of S. chinensis has not been sufficiently well described. In addition, the molecular data from species of the Subuluroidea are extremely limited. METHODS: The detailed morphology of S. chinensis was studied using light microscopy and, for the first time, scanning electron microscopy, based on newly collected specimens from the little owl Athene noctua (Scopoli) (Strigiformes: Strigidae) in China. The internal transcribed spacer (ITS) of ribosomal DNA and mitochondrial cytochrome c oxidase subunit 1 (cox1) target regions of S. chinensis were first amplified by polymerase chain reaction (PCR), then sequenced and analysed for the molecular identification of this species. RESULTS: Our SEM observations showed for the fist time the detailed morphology of the cephalic extremity, precloacal pseudo-sucker, caudal papillae, gubernaculum, phasmids and vulva of S. chinensis, and also determined the presence of a small, single medio-ventral precloacal papilla in the male. Moreover, we detected the presence of 0.08-0.40% and 0-1.30% nucleotide divergence among different individuals of S. chinensis in the ITS and cox1 regions, respectively. The supplementary morphological characters and genetic data will be very useful for the diagnosis of this poorly known species.

Resistance and tolerance to mixed nematode infections in chicken genotypes with extremely different growth rates.

Fast growing broilers are less able to cope with fitness related challenges. As the allocation of metabolic resources may be traded off between performance and defence functions in parasitized hosts, we hypothesized that fast growing broilers are more sensitive to mixed nematode infections compared with slower growing genotypes under the same environmental conditions. Therefore, we compared male birds of genotypes selected for either meat production (Ross-308, R) or egg production (Lohmann Brown Plus, LB) or for both purposes (Lohmann Dual, LD), to assess their resistance and tolerance to mixed nematode infections with Ascaridia galli and Heterakis gallinarum. While infections reduced feed intake in all three genotypes, feed conversion efficiency was not affected. Infections impaired growth performance only in R birds, indicating lower tolerance in the fast growing genotype compared with slower growing LB and LD genotypes. Impaired tolerance in R birds was associated with a relative nutrient scarcity due to an infection-induced lower feed intake. Resistance to experimentally induced infections depended on host genotype as well as on the worm species involved. Overall, the A. galli burden was higher in R than LB, whereas the burden of LD was not different from that of R and LB. In contrast, the H. gallinarum burden of first generation worms was similar in the three genotypes. Susceptibility to re-infection with H. gallinarum was higher in LB than in LD, whereas very low levels of re-infection were observed in R birds. Our data collectively suggest that resistance and tolerance to mixed nematode infections are sensitive to growth rate in chickens. These differences amongst genotypes may partly be associated with a mismatch between the actual nutrient supply and genotype-specific nutrient requirements.

Gastrointestinal helminths of backyard chickens in selected areas of West Shoa Zone Central, Ethiopia.

Gastrointestinal parasites of chickens are prevalent in many parts of the world including Ethiopia. This study was conducted with backyard chickens in Ambo, Holeta and, Dire Inchini in the West Shoa zone with the objectives of estimating the prevalence of gastrointestinal helminth infections, identifying the species present and determining associated risk factors. A cross-sectional study was conducted using 252 chickens purchased from local markets. Chickens were killed humanely and gastrointestinal tracts were examined for adult helminths. Identification of the helminths was performed using morphology and microscopy. The overall prevalence of helminth parasites in chickens was 92.1% (232/252) [95% confidence interval (CI): 88.0% - 95.1%]. 80.2% (204/252) [95% CI: 75.3% - 86.9%] and 77.8% (196/252) [95% CI: 72.1% - 82.8%] of chickens were infected with diverse nematode and cestode species, respectively. Parasitological examination revealed the presence of three nematode and five cestode species. Ascaridia galli (69.8%) and Heterakis gallinarum (13.5%) were the dominant nematode species and Railletina tetragona (54.0%) and Railletina echinobothrida (46.8%) were the most prevalent species of cestodes identified. A significant difference (p < .05) was observed between the prevalence of nematode parasites and sex, age, and origin of the chicken. Similarly, sex and origin of the chickens were significantly different with the prevalence of cestode infections. Higher prevalence was observed in male versus female chickens, in young versus adult chickens and in chickens from Holeta and Direinchin compared to Ambo. In contrast, weight, health status, diarrhea status, and age (for cestodes) were not significantly associated with nematode and cestode infection. In conclusion, the present study detected a high prevalence of diverse types of gastrointestinal helminths in backyard chickens, which could result in poor health and reduce productivity. Therefore, the present study strongly suggests appropriate and strategic control of helminthiasis to improve the health and output of backyard chickens in the study areas.

Helminth community and host dynamics in northern bobwhites from the Rolling Plains Ecoregion, U.S.A.

One hundred and sixty-one northern bobwhites (Colinus virginianus; hereafter 'bobwhite') were examined from the Rolling Plains ecoregion of Texas and western Oklahoma from 2011 to 2013. Complete necropsies yielded 13 species, of which two are new host (Gongylonema phasianella) and region (Eucoleus contortus) records and three (Dispharynx nasuta, Tetrameres pattersoni and Oxyspirura petrowi) are known to cause morbidity and mortality. Of the species found, Aulonocephalus pennula commonly occurred, Oxyspirura petrowi was intermediate in prevalence, and the remaining species were rare. Species richness was similar compared to studies from the southeastern U.S., but higher than studies from the same region. In addition, 12 of the 13 species were heteroxenous helminths, supporting the theory that heteroxenous helminths in semi-arid regions are more successful than monoxenous helminths. Prevalence and abundance of A. pennula and O. petrowi were higher in adult bobwhites than in juveniles. Abundance of A. pennula and O. petrowi was higher at southern locations compared to northern locations in the study area. Our study is the first to provide a current assessment of the bobwhite helminth community across the Rolling Plains ecoregion of the U.S.

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

The genus Megalobatrachonema is a rare group of nematode parasites within Ascaridida. The systematic status of Megalobatrachonema in the superfamily Cosmocercoidea (Ascaridida) has long been controversial. The relationship of Megalobatrachonema and Chabaudgolvania remains unsolved. In the present study, a new species of Megalobatrachonema, M. hainanensis sp. nov., was described based on specimens collected in Amolops hainanensis (Boulenger) and Hylarana spinulosa (Smith) (Amphibia: Anura) from Hainan Island, China. The large ribosomal DNA (28S) and internal transcribed spacer (ITS1-5.8S-ITS2) were also sequenced for molecular identification and phylogenetic study. Phylogenetic analyses using maximum likelihood (ML) inference and Bayesian inference (BI) based on 28S and ITS1 sequence data, respectively, supported that Megalobatrachonema is a member of the family Kathlaniidae. In addition, the genetic comparison and phylogenetic results based on ITS1 sequence data also supported that the genus Chabaudgolvania should be considered as a synonym of Megalobatrachonema.

Endoparasites in Limnonectes magnus (Anura, Dicroglossidae) from Samar Island, Philippines with description of a new species of Aplectana (Nematoda, Cosmocercidae).

Aplectana samarensis sp. nov. (Ascaridida, Cosmocercidae) from the intestines of Limnonectes magnus (Anura, Dicroglossidae) is described and illustrated. Aplectana samarensis sp. nov. represents the 53rd species assigned to the genus and the 6th species reported from the Oriental region. It is easily separated from the 5 species previously reported from the region by the presence of a gubernaculum and the distribution pattern of male caudal papillae: A. macintoshii has an irregular pattern, no precloacal papillae in rows; both A. akhrami and A. dubrajpuri lack a gubernaculum; A. duttaphryni has 3 pairs of precloacal papillae forming 2 rows; A. ranae has 7 pairs of precloacal papillae forming 2 rows; A. samarensis sp. nov. has 4 pairs of precloacal papillae in 2 rows. In addition to the new species, individuals of Falcaustra dubia and Pseudoacanthocephalus bufonis as well as cestode plerocercoids were also found.

Morphological and molecular evidence for a new species of the genus Cosmocercoides Wilkie, 1930 (Ascaridida: Cosmocercidae) from the Asiatic toad Bufo gargarizans Cantor (Amphibia: Anura).

A new cosmocercid species, Cosmocercoides qingtianensis sp. n., collected from the intestine of the Asiatic toad Bufo gargarizans Cantor (Amphibia: Anura) is described using integrated approaches, including light and scanning electron microscopy, and sequencing and analyzing the ribosomal [small ribosomal DNA (18S) and internal transcribed spacer (ITS)] and mitochondrial [cytochrome c oxidase subunit 1 (cox1)] target regions, respectively. The new species can be distinguished from its congeners by the combination of the following morphological characters, including the large body size, the presence of lateral alae and somatic papillae in both sexes, the length of spicules, the particular morphology and length of gubernaculum, the number, arrangement and morphology of caudal rosettes, the presence of large medioventral precloacal papilla and the long tail. Our molecular analysis revealed the level of intraspecific genetic variation of C. qingtianensis sp. n. distinctly lower than that of the interspecific genetic variation in the ITS and cox1 regions. However, there are some overlaps in the range of intra- and interspecific 18S sequence divergence between the new species and some closely related species. The results of molecular analysis supported the validity of the new species based on the morphological observations. The 18S, ITS, and cox1 regions of C. pulcher collected from Bufo japonicus formosus in Japan were also sequenced and analyzed. The results showed a low level of intraspecific genetic variation in 18S and ITS regions (0-0.12% and 0-0.23% nucleotide differences, respectively), but a relatively high level of intraspecific genetic variation in cox1 region (0.78-4.69% nucleotide differences). In addition, it seems more powerful and practical to use the cox1 region as a genetic marker for the accurate identification and differentiation of species of Cosmocercoides than the 18S and ITS regions, especially for the closely related species.

Helminth parasites of Mabuya arajara Rebouças-Spieker, 1981 (Lacertilia: Mabuyidae) from Chapada do Araripe, northeastern Brazil.

We provide data on the helminth fauna from the digestive tract of the lizard Mabuya arajara Rebouças-Spieker, 1981 from Chapada do Araripe, northeastern Brazil. Seventy one of the 127 lizards examined (56%) were infected with four nematode species: Physalopteroides venancioi and Physaloptera sp. (Physalopteridae), Strongyluris oscari (Heterakidae), and Parapharyngodon alvarengai (Pharyngodonidae), the latter being the component species (prevalence 53.5%; mean intensity of infection 3.37 ± 2.0; discrepancy index D = 0.69). The helminth P. alvarengai infected M. arajara throughout the year and showed increased infection rates in July, at the beginning of the dry season. In addition to the relationship with seasonality, lizards with greater body length and/or body mass were more infected. Relationships between number of parasites and body mass and with the sexes of lizards, on the other hand, were not found. Mabuya arajara represents a new host for these nematodes. This study contributes to the knowledge of the helminth fauna associated with the digestive tract of lizards from South America and the Caatinga domain.

Nematode parasites of Duttaphrynus stomaticus (Lutken, 1864) (Amphibia: Anura) with description of a new species of Rhabdias Stiles and Hassall, 1905 (Nematoda: Rhabdiasidae) from Dehradun (Uttarakhand), India.

Rhabdias stomatica sp. nov. from the lungs of Duttaphrynus stomaticus (Lutken, 1864) from Dehradun, Uttarakhand, India is described and illustrated. Rhabdias stomatica sp. nov. is the 16th species described from the Oriental biogeographical region and the 8th species from India. The new species is differentiated from the closely related Oriental species in having 4 weakly developed lips, a trapezoidal shaped buccal cavity, different position of nerve ring and in the esophagus/body length ratio. In addition, to the new species found in the lungs, mature specimens of Aplectana macintoshii (Stewart, 1914) Travassos, 1931 and larvae representing two unidentified species of nematode were found in the large intestine of the D. stomaticus.

A new species of Aplectana (Nematoda, Cosmocercidae) in Goniurosaurus bawanglingensis (Squamata, Eublepharidae), from Hainan Province, China.

Aplectana hainanensis sp. nov. (Ascaridida, Cosmocercidae) from the intestines of Goniurosaurus bawanglingensis (Squamata, Eublepharidae) is described and illustrated. Aplectana hainanensis sp. nov. represents the 52nd species assigned to the genus and the 5th species reported from the Sino-Japanese region. It is easily separated from the 4 species previously reported from the region by the distribution pattern of male caudal papillae: A. macintoshii has an irregular pattern; A. hylae has no precloacal papillae; A. fujianae has 1 pair of precloacal papillae; A paucipapillosa has 3 pairs of precloacal papillae; Aplectana hainanensis sp. nov. has 7 pairs of precloacal papillae.

Two nematode species from freshwater and marine fishes in Thailand, including Ascarophis scatophagi sp. nov. (Cystidicolidae) from Scatophagus argus (Scatophagidae).

One new and one known species of parasitic nematodes are reported from Thailand for the first time: Falcaustra kaverii (Karve et Naik,1951) (Kathlaniidae) from the intestine of the freshwater fish Poropuntius deauratus (Valenciennes) (Cyprinidae) (new host record) and Ascarophis scatophagi sp. nov. (Cystidicolidae) from the intestine of the marine fish Scatophagus argus (Linnaeus) (Scatophagidae). The morphology of both these species was studied with the use of light (LM) and scanning electron microscopy (SEM) (the latter method used for F. kaverii for the first time). The new species (A. scatophagi) is mainly characterized by nonfilamented, markedly elongate-oval eggs (size 42-45 × 18 µm), spicules 555-642 µm and 105-150 µm long, the muscular/glandular oesophagus length ratio (1:13-34), bifurcate deirids, the length of the female tail (159-249 µm) and cephalic structures typical of the nominotypical subgenus Ascarophis. Representatives of Falcaustra Lane, 1915 and Ascarophis van Beneden, 1871 were not previously reported from fishes in Thai waters.