Dentition patterns and molecular diversity of Mastophorus muris (Gmelin, 1790) (Nematoda: Spiruroidea) support a host-associated subdivision.

Mastophorus muris (Gmelin, 1790) is a globally distributed parasitic nematode of broad range mammals. The taxonomy within the genus Mastophorus and the cryptic diversity among the genus are controversial among taxonomists. This study provides a detailed morphological description of M. muris from Mus musculus combined with a molecular phylogenetic approach. Moreover, descriptions and molecular data of M. muris from non-Mus rodents and wildcats complement our findings and together provide new insights into their taxonomy. The analysis of M. muris was based on light microscopy and scanning electron microscopy. The morphological description focused on the dentition pattern of the two trilobed pseudolabia. Additionally, we described the position of the vulva, arrangement of caudal pairs of papillae, spicules and measured specimens from both sexes and the eggs. For the molecular phylogenetic approach, we amplified the small subunit ribosomal RNA gene and the internal transcribed spacer, and the cytochrome c oxidase subunit 1. Mastophorus morphotypes based on dentition patterns and phylogenetic clustering indicate a subdivision of the genus in agreement with their host. We recognize two groups without a change to formal taxonomy: One group including those specimens infecting Mus musculus, and the second group including organisms infecting non-Mus rodents. Our genetic and morphological data shed light into the cryptic diversity within the genus Mastopohorus. We identified two host-associated groups of M. muris. The described morphotypes and genotypes of M. muris allow a consistent distinction between host-associated parasites.

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.

Morphology and genetic characterization of Physaloptera sibirica Petrow & Gorbunov, 1931 (Spirurida: Physalopteridae), from the hog-badger Arctonyx collaris Cuvier (Carnivora: Mustelidae), with molecular phylogeny of Physalopteridae.

BACKGROUND: Nematodes of the family Physalopteridae (Spirurida: Physalopteroidea) commonly parasitize the alimentary canal of all major vertebrate groups. However, many physalopterid species are not adequately described, especially regarding the detailed morphology of the cephalic end. The current genetic database for Physaloptera species is still very limited, which seriously hampers molecular-based species identification. Additionally, the systematic status of some genera and the evolutionary relationships of the subfamilies in the Physalopteridae remain under debate. METHODS: New morphological data for Physaloptera sibirica was gathered using light and scanning electron microscopy based on newly collected specimens from the hog badger Arctonyx collaris Cuvier (Carnivora: Mustelidae) in China. Six different genetic markers, including nuclear small ribosomal DNA (18S), large ribosomal DNA (28S) and internal transcribed spacer (ITS), mitochondrial cytochrome c oxidase subunit 1 (cox1) and subunit 2 (cox2), and the 12S small subunit ribosomal RNA gene of P. sibirica were sequenced and analyzed for the first time to our knowledge. Additionally, to construct a basic molecular phylogenetic framework for the Physalopteridae, phylogenetic analyses were performed based on the cox1 and 18S + cox1 genes using maximum likelihood (ML) and Bayesian inference (BI) methods. RESULTS: Scanning electron microscopy (SEM) observation displayed the details of the cephalic structures, deirids, excretory pore, caudal papillae, vulva, phasmids and egg of P. sibirica for the first time to our knowledge. Pairwise comparison of the sequences obtained for P. sibirica did not reveal intraspecific divergence regarding the 18S, 28S, cox1 and 12S genetic markers and a low level of divergence in the ITS (0.16%) and cox2 (2.39%) regions. Maximum likelihood and Bayesian inference analyses showed that the representatives of Physalopteridae formed two major clades (species of Physalopterinae + Thubunaeinae parasitic in terrestrial vertebrates and Proleptinae only occurring in marine or freshwater fishes). Turgida turgida was found nested among representatives of Physaloptera. Physaloptera sibirica clustered together with P. rara. Physalopteroides sp. (Thubunaeinae) formed a sister relationship to the physalopterine Abbreviata caucasica. CONCLUSIONS: Physaloptera sibirica was redescribed, which is the fourth nematode parasite reported from the hog badger A. collaris, and A. collaris represents a new host for P. sibirica. The phylogenetic results challenged the validity of the subfamily Thubunaeinae and of the genus Turgida and supported dividing the family Physalopteridae into two subfamilies, Physalopterinae and Proleptinae. However, we do not make any immediate systematic changes in the Physalopteridae, because a more rigorous study with broader representation of the Physalopteridae is required. These present findings contribute to morphologically identifying P. sibirica more accurately and provide new insights into the systematics of the Physalopteridae.

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

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

Redescription of the two most recorded Physaloptera (Nematoda: Physalopteridae) parasitizing lizards in the Americas: first step towards a robust species identification framework.

Despite being the two most recorded species of Physaloptera from lizards in the Americas, P. retusa and P. lutzi are either incompletely described or have accumulated inaccurate morphological data through the years. Here, we redescribe both species from Tropidurus torquatus in the State of Minas Gerais, Brazil, including evaluation of specimens from the Coleção Helmintológica do Instituto Oswaldo Cruz. In P. retusa, the presence and location of amphids, presence and pattern of porous areas on pseudolabia, detailed pattern of cuticular ornamentations on ventral surface of the caudal bursa, structure of cloacal labia, presence of dome-shaped elevation between the last pair of postcloacal papillae and location of phasmids in males, were revealed for the first time. Additional morphometric data are also provided. In P. lutzi, the detailed morphological analysis revealed for the first time, porous areas on pseudolabia, as well as presence of amphids, phasmids, and the detailed ornamentation and papillae arrangement on the male bursa. Also, the presence of an internal tripartite and an external triangular labial tooth in the specimens were observed to be constant, diverging from the assertions by other authors. Finally, in P. lutzi was possible to observe that deirids are consistently located close to muscular oesophagus base with excretory pore slightly posterior to it, and the vulva is always close to anal aperture. The present observations confirmed the validity of P. lutzi and strengthened its taxonomic diagnosis. An up-to-date list of records of both species is provided, including a brief discussion on their host spectrum and geographic range.

Ascarophisnema hoiae n. sp. (Nematoda: Cystidicolidae), from the stomach of the trumpeter whiting, Sillago maculata Quoy & Gaimard (Perciformes: Sillaginidae) from Moreton Bay, Queensland, Australia.

Ascarophisnema hoiae n. sp. (Nematoda: Cystidicolidae) is described from the stomach of the trumpeter whiting, Sillago maculata Quoy & Gaimard (Perciformes: Sillaginidae) from Moreton Bay, Queensland, Australia. It differs morphologically from the only other valid congener, A. tridentatum Moravec & Justine, 2010 in the shape of the sub-labium and in the lengths of the spicules and the morphology of their distal tips (bifid). It represents the first record of this genus from Australia and appears to be highly oioxenous, having been found only in this host species among 133 other species of fish examined at the same locality.

A new species of Physaloptera (Nematoda: Spirurida) from Proechimys gardneri (Rodentia: Echimyidae) from the Amazon rainforest and molecular phylogenetic analyses of the genus.

Nematodes of the genus Physaloptera are globally distributed and more than 100 species are known. Their life cycle involves insects, including beetles, cockroaches and crickets, as intermediate hosts. This study describes a new species of Physaloptera and reports molecular phylogenetic analyses to determine its relationships within the family Physalopteridae. Physaloptera amazonica n. sp. is described from the stomach of the caviomorph rodent Proechimys gardneri collected in the Amazon rainforest in the state of Acre, Brazil. The species is characterized by the male having the first and second pair of sessile papillae asymmetrically placed, lacking a median papilla-like protuberance between the third pairs of sessile papillae, differentiated by size and shape of the spicules, while females have four uterine branches. For both nuclear 18S rRNA and MT-CO1 gene-based phylogenies, we recovered Turgida sequences forming a clade nested within Physaloptera, thus making Physaloptera paraphyletic to the exclusion of Turgida, suggesting that the latter may have evolved from the former monodelphic ancestral state to a derived polydelphic state, or that some species of Physaloptera may belong to different genera. Relationships between most taxa within Physaloptera were poorly resolved in our phylogenies, producing multifurcations or a star phylogeny. The star-like pattern may be attributed to evolutionary processes where past simultaneous species diversification events took place. Physaloptera amazonica n. sp. formed an independent lineage, separately from the other species of Physaloptera, thus supporting the status of a new species. However, all molecular data suggested a closer relationship with other Neotropical species. In conclusion, we added a new species to this already largely diverse genus Physaloptera, bringing new insights to its phylogenetic relationships. Further analyses, adding more species and markers, should provide a better understanding of the evolutionary history of physalopterids.

Taxonomic status of Rhabdochona ictaluri (Nematoda: Rhabdochonidae) based on molecular and morphological evidence.

The genus Rhabdochona includes more than 100 species infecting freshwater fishes in all zoogeographical regions of the world. In Mexico, 12 nominal species of Rhabdochona have been recorded. Of these, Rhabdochona ictaluri was originally described as a parasite of endemic catfishes of the family Ictaluridae; however, the species was later considered on morphological grounds as a junior synonym of Rhabdochona kidderi. In this study, newly sampled specimens of R. ictaluri were obtained from the type host and type locality and were used to perform a detailed morphological analysis and molecular phylogenetic inferences through one mitochondrial and two nuclear genes; data were used in an integrative taxonomy context to test the taxonomic status of R. ictaluri. This approach proved to be very useful to confirm the validity of this species, and robust species limits were established between these two putative species considering morphology, molecular data, host association, and biogeography.

Tetrameres globosa (Linstow, 1879) (Nematoda, Tetrameridae) ­ a nematode of the Eurasian coot Fulica atra (Linnaeus, 1758) recorded for the first time in Poland

During parasitological studies of 23 Eurasian coot Fulica atra (Linnaeus, 1758), 91 nematodes were isolated. Three of them, found in the proventriculus, were identified as Tetrameres globosa (Linstow, 1879). This paper presents the morphological characteristics of the discovered males of T. globosa.

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.

Morphological and molecular identification of Habronema spp. (Nematoda: Habronematidae) from donkeys in Xinjiang, China, and notes on the taxonomical status of Habronema majus (Creplin, 1849) and H. microstoma (Schneider, 1866).

Habronematid nematodes were collected from the stomachs of donkeys, Equus asinus L., in the Tarim Basin, Xinjiang, China. After examination by light and scanning electron microscopy, Habronema muscae (Carter, 1861) and H. majus (Creplin, 1849) were identified. The morphology of our specimens representing H. muscae (Carter, 1861) agreed well with previous redescriptions in the shape of the lateral lips, origin of the lateral alae, ratio of left and right spicules, and number and arrangement of caudal papillae. However, H. majus (Creplin, 1849) differs from H. microstoma (Schneider, 1866) in the arrangement of the caudal papillae in the male. Moreover, molecular analysis also showed interspecific differences of 26.2-28.2% in ITS2 and 8.6-8.9% in cox1 between H. majus and H. microstoma, a divergence much higher than the known intraspecific variation of Habronema spp. (6.6-8.7% in ITS2; 0.2-2.2% in cox1). The results indicate that both H. microstoma (Schneider, 1866) and H. majus (Creplin, 1849) are valid species.

A review of Gongylonema spp. (Nematoda: Gongylonematidae) in North American rodents with description of a new species from the cotton rat, Sigmodon hispidus (Mammalia: Cricetidae).

Gongylonema archboldi n. sp. (Nematoda: Gongylonematidae) is described from tunnels in the gastric mucosa of the stomach of the cotton rat (Sigmodon hispidus) from Highlands County, Florida, U.S.A. Measurements are also given for specimens from cotton mice (Peromyscus gossypinus), oldfield mice (Peromyscus polionotus), Florida mice (Podomys floridanus), and golden mice (Ochrotomys nuttalli) from the same locality. Additional specimens were collected from the cotton rat and the rice rat (Oryzomys palustris) from Berry Island, San Patricio County, Texas. The new species is differentiated from congeners by a combination of the following characters: length of the left spicule, length and shape of the gubernaculum, distribution of cuticular bosses, length of esophagus, and distance of the vulva from the posterior end. The status of the genus Gongylonema in North American rodents is reviewed.

Redescription of two species of cystidicolid nematodes (Spirurina: Cystidicolidae) from Notopterus notopterus (Osteichthyes) in Thailand.

Two nematode species, Pseudoproleptus notopteri (Karve et Naik, 1951) and Spinitectus notopteri Karve et Naik, 1951 (both Cystidicolidae), are redescribed based on light and scanning electron microscopical studies of specimens collected from the digestive tract of the freshwater fish Notopterus notopterus (Pallas) (Notopteridae, Osteoglossiformes) in Thailand. Some new important morphological features, such as a detailed structure of the cephalic end and the presence of bifurcate deirids and a ventral median caudal protuberance in male, are reported for the former species (P. notopteri), which is provisionally assigned to Pseudoproleptus Khera, 1955; Notopteroides notopteri Chakravarty et Majumdar, 1962, Pseudoproleptus satendri Sahay, 1967, P. lamyi Le-Van-Hoa et Bui-Thi Lien-Huong, 1969, P. gomtii Gupta et Bakshi, 1984. P. sprenti Gupta et Masoodi, 1986 and P. thapari Gupta et Naiyer, 1992 are considered its junior synonyms. The first study of S. notopteri by SEM showed its morphological similarity with S. mastacembeli Karve et Naik, 1951, from which it clearly differs by the structure of eggs; Spinitectus alii Kalyankar, 1970, S. bengalensis Chakravarty, Sain et Majumdar, 1961, S. gomalensis Siddiqui et Kattak, 1984 and S. thapari Ali, 1957 are considered to be junior synonyms of S. notopteri. Pseudoproleptus notopteri and Spinitectus notopteri are reported from Thailand for the first time.

Intraspecific and interspecific genetic variation of Gongylonema pulchrum and two rodent Gongylonema spp. (G. aegypti and G. neoplasticum), with the proposal of G. nepalensis n. sp. for the isolate in water buffaloes from Nepal.

The gullet worm (Gongylonema pulchrum) has been recorded from a variety of mammals worldwide. In an earlier study, we demonstrated two separate transmission cycles in cattle (Bos taurus) and wild mammals in Japan based on nucleotide sequences of the ribosomal RNA gene (rDNA) and cytochrome c oxidase subunit I (cox-1) region of mitochondrial DNA of multiple isolates of different origins. Our earlier study additionally demonstrated two major cox-1 haplotypes of G. pulchrum prevalent in cattle in Japan. In the present study, we collected G. pulchrum from cattle and goats (Capra hircus) in Alashan League, Inner Mongolia, China; Gongylonema aegypti from spiny mice (Acomys dimidiatus) in the Sinai Peninsula, Egypt; and Gongylonema neoplasticum from a black rat (Rattus rattus) in Okinawa Island, Japan, to analyze their genetic relationships with G. pulchrum in Japan. The gullet worms from Alashan League had almost identical rDNA nucleotide sequences and two cox-1 haplotypes as seen in G. pulchrum from the cattle in Japan. The two rodent Gongylonema spp. had distinct rDNA nucleotide sequences compared with those of G. pulchrum; only the 18S and 5.8S rDNA sequences showed high identities at 97.2-98.7%, while the remaining sequences were less than 75% identical. The 18S, 5.8S, and 28S rDNA sequences of the two rodent Gongylonema spp. showed nucleotide identities of 99.8% (1811/1814), 100% (158/158), and 98.9% (3550/3590), respectively. The cox-1 regions showed 91.6% (338/369)-92.1% (340/369) identities, with completely identical amino acid sequences. The genetic diversities of three distinct Gongylonema spp. and their possible intraspecific genetic variation may allow us to resolve the taxonomic position of Gongylonema spp. which display few obvious morphological differences from their congeners. Consequently, the Gongylonema isolate from water buffaloes (Bubalus bubalis) in Nepal reported in our previous study is concluded to be a new species, and Gongylonema nepalensis n. sp. is erected for it.

Molecular and morphological comparison of two different types of Habronema muscae (Nematoda: Habronematidae) in horse.

Habronema muscae is a spirurid nematode that undergoes developmental stages in the stomach of equids, causing chronic catarrhal gastritis. Despite preceding investigations have developed polymerase chain reaction (PCR)-based assays for molecular diagnosis, we aimed to assess the applicability of cytochrome c oxidase subunit 1 (cox1) sequences to identify the H. muscae infection and to assess the level of intraspecific variations in this parasite obtained from affected horses in Southern Iran. According to the morphological characterizations, two different isolates of H. muscae were identified. Although the majority of the recovered specimens had normal characterizations of H. muscae, a number of parasites showed an abnormal feature as large, asymmetrical, and thick cuticular extensions was observed at their anterior end (head region) in gross and histologic examinations. Unexpectedly, molecular assay disclosed that both morphologically distinct samples were completely identical to each other based on cox1 sequence. Multiple alignment of the cox1 amino acid sequences showed that all polymorphism sites were silent. Also, phylogenetic analysis provided strong support that H. muscae form a sister group to Spirocerca lupi and Thelazia callipaeda.

A new species of Rhabdochona Railliet, 1916 (Nematoda: Rhabdochonidae) from cyprinid fishes in the Western Ghats Region, India.

A new nematode species, Rhabdochona (Globochona) puntii n. sp. (Rhabdochonidae), is described based on specimens collected from the intestine of the pool barb Puntius sophore (Hamilton) and Neolissochilus hexastichus (McClelland) (both Cyprinidae) from the Gadhena River, the Western Ghats, Maharashtra State, India. The nematode was also found in Wallago attu (Bloch & Schneider) which probably acts as postcyclic host. Rhabdochona (Globochona) puntii n. sp. differs markedly from its congeners in the body size, the number and distribution of caudal papillae, in the presence of an unpaired papilla-like structure on the anterior cloacal lip, and in having unusual shape and structure of the terminal crown of mucrons. This is the seventh species of the subgenus Globochona Moravec, 1972 reported from freshwater Indian fishes.

Physaloptera bainae n. sp. (Nematoda: Physalopteridae) parasitic in Salvator merianae (Squamata: Teiidae), with a key to Physaloptera species parasitizing reptiles from Brazil.

Physaloptera bainae n. sp. (Nematoda: Physalopteridae) from stomach of the large "tegú" lizard Salvator merianae (Squamata: Teiidae), collected in an ecological park that is part of the Atlantic Rainforest biome in Juiz de Fora, Minas Gerais, Brazil, is described. The new species which has females with didelphic uterus, is the only species of the genus exhibiting external teeth in the form of 4 spines that are organized in a cross-shaped pattern at the anterior apical end, with 2 minute adcloacal papillae on the anterior part of cloacal aperture in males and a large cuticular expansion at the anterior end of females. Moreover, P. bainae n. sp. can be differentiated from the other congeners by the combination of other features, e.g., number (23) and pattern of caudal papillae, spicule size (left 554-600; right 589-617) and vulval position (on the first third of body), and because the specimens are particularly large and robust. Physaloptera monodens is considered a junior synonym of P. obtusissima. In addition, a key to Physaloptera species parasitizing reptiles from Brazil is provided.

Pterygodermatites (Mesopectines) niameyensis n. sp. (Nematoda: Rictulariidae), a parasite of Mastomys natalensis (Smith, 1834) (Rodentia: Muridae) from Niger.

Pterygodermatites (Mesopectines) niameyensis n. sp. is described from Mastomys natalensis in Niamey/Niger (West Africa). It differs from other species of same subgenus by the morphology of the head, which presents 4 simple cephalic papillae and nearly axial oral opening, a number of caudal papillae, precloacal cuticular formations, and the spicule length/body length ratio. Scanning electron microscopy shows the presence of 2 pairs of lateral sensory structures for male worms.

The morphology and systematics of Rhabdochona paski Baylis, 1928 (Nematoda: Rhabdochonidae), a widespread parasite of freshwater fishes in Africa.

Nematodes of the genus Rhabdochona Railliet, 1916, identified as R. paski Baylis, 1928, were collected from the intestine of Hydrocynus forskahlii (Cuvier) (Characiformes: Alestidae), Oreochromis niloticus (Linnaeus) and Tilapia zillii (Gervais) (both Perciformes: Cichlidae) from Lake Turkana, Kenya during 2007-2009. Their morphology was studied in detail using light and scanning electron microscopy. Paratypes of R. paski and museum specimens of R. congolensis Campana-Rouget, 1961 from six other host species were examined for comparison. Based on these studies and the available literature data, Rhabdochona congolensis, R. aegyptiaca El-Nafar & Saoud, 1974 (emend.) and R. vesterae Boomker & Petter, 1993 are considered to be junior synonyms of R. paski. The occurrence of this widely distributed African nematode in many fish species belonging to different families and orders suggests that most of them are probably not definitive hosts of this parasite, but only serve as paratenic, paradefinitive or postcyclic hosts (sensu Odening, 1976). True definitive hosts of R. paski appear to be characiform species belonging to some genera (e.g., Alestes, Brycinus, Hydrocynus) of the family Alestidae.

First case of human gongylonemosis in France.

Gongylonema spp. are cosmopolitan spirurid nematodes that are common parasites of wild and domesticated mammals and birds. Gongylonema pulchrum Molin, 1857 is most common in ruminants, where it invades mucosa and submucosa of the mouth, tongue, oesophagus and forestomachs. It extremely rarely occurs in man, and fewer than 60 cases have been reported worldwide. We report a case from the Alsace region, which appears to be the first case of human gongylonemosis described in France.