Stoma and intestine ultrastructure of the marine free-living nematode Odontophora deconincki (Nematoda: Araeolaimida: Axonolaimidae)

Summary The fine morphology of the buccal capsule and intestine (midgut) of the marine free-living nematode Odontophora deconincki was investigated. The cheilostome is armed with six equal claw-like odontia that can evert radially by opening the mouth. Light-refracting accessory buccal structures within the cheilostomatal cuticle alternate with odontia and consist of two elements: anterior armilloids and posterior granular armilliths. The buccal cavity (pharyngostome) is surrounded by a complex of longitudinal and oblique muscles partially attached to the cheilostome cuticle at the sites of the accessory buccal structures and enabling a wide opening of the mouth. With the described stoma condition, the nematode probably scrapes food particles from the substrate surface. In cross-section, the midgut consists of 5-7 cells that appear uniform throughout its length. An extracellular matrix (glycocalyx) over the microvillar brush varies in thickness and stratification depending on presence or absence of food content in the lumen. Abundant spherocrystals (globular inclusions with concentric striations) were present in all gut cells. No indication of endocytosis or digestive vacuoles was observed in the gut cells and extracellular digestion predominates. Most specimens had a gut content formed from a long cylinder of compressed flocculent material with some barely identifiable components and few spherocrystals expelled from the enterocytes. We assume that the nematode diet comprises a wide range of objects, mainly eukariotic epigrowth organisms, which are shorn off and scraped from the surface of sand grains and then ingested.

Gastrointestinal nematodes of freshwater fish from Pilcomayo River, Argentina, including description of a new species of Procamallanus (Spirocamallanus)

Helminthological examination of viscera of six freshwater fish species, collected from Misión la Paz, Pilcomayo River, Province of Salta, Argentina, revealed the presence of five species of parasitic nematodes belonging to the Camallanidae, Cystidicolidae, Cucullanidae and Anisakidae The material also contained one unknown species, Procamallanus (Spirocamallanus) tomsici sp. nov. collected from Pimelodus albicans, Pygocentrus nattereri and Hoplias misionera. This species is distinguished from its congeners all over de world by possessing six pores distinctly surrounding the mouth aperture, a buccal capsule with 3–4 spiral thickenings complete, females possessing a lateral cuticular ornamentation along the body, and two pairs of preanal and three pairs of postanal papillae in males. The findings represent new hosts and geographical records.

Molecular detection of Murshidia linstowi in a free-ranging dead elephant calf

Gastrointestinal helminths are ubiquitous in both domestic and wild animals. Infections are often sub-clinical except in circumstances of destabilization of host-parasite equilibrium by innate or environmental factors. The present case deals with microscopic and molecular diagnosis of Murshidia linstowi recovered from an elephant. A post-mortem examination of a free-ranging juvenile male elephant calf that had died of electrocution in Athagarh Wildlife Division revealed the presence of slender, whitish nematodes in the stomach. No gross lesions were noticed either in the site of predilection or any other internal organs. The average length of the parasites was 3.8cm. These parasites were collected for further gross as well as microscopic examination following routine parasitological techniques. Temporary mounts prepared after cleaning the nematodes in lactophenol were observed under a microscope. Morphological features such as a well-developed mouth collar, large and globular buccal capsule with fine tubercles, cone shaped oesophageal funnel, short bursa having indistinctly divided lobes and closely apposed ventral rays and stout spicules with club shaped tips bent dorsally corroborated with that of M.linstowi (male). Amplification of the rDNA from the internal transcribed spacer (ITS) region using universal nematode primers NC2 and NC5 revealed a product size of 870bp. The PCR product was subjected to sequencing followed by NCBI-BLAST which revealed 98% homology with M. linstowi. A phylogenetic study showed a maximum similarity with M.linstowi recovered from elephants in Kenya. This particular nematode species belonging to the family Strongylidae and sub-family Cyathostominae appears to be the first documented report in India.

Buccal capsule and intestine ultrastructure of the marine predatory nematode Sphaerolaimus balticus (Monhysterida: Sphaerolaimidae)

Summary The ultrastructural morphology of the buccal capsule and intestine (mid-gut) of the predatory marine nematode Sphaerolaimus balticus is investigated. The major part of the voluminous barrel-shaped buccal capsule is made up of strongly modified somatic cuticle and hence presents itself as an intricately differentiated cheilostome. The latter consists of three compartments: i.e., i) labial region; ii) striated region with six rows of fine longitudinal ribs; and iii) shagreen band penetrated by about ten projections of arcade tissue. The gymnostome and telostome are narrow and together constitute a small posterior portion of the buccal capsule. The mouth is evidently opened by contraction of anterior longitudinal somatic muscles. The intestine is characterised by a very thin and homogenous basal lamina. The cytoplasm of the enterocytes contains lipid granules, large electron-light vacuoles and rounded concentric inclusions in membranous vacuoles. Apical microvilli are separated from the lumen by a dense three-layered glycocalyx resembling the peritrophic membrane in the intestine of arthropods. The glycocalyx is only a supportive structure of the mid-gut. The most peculiar features of the intestine are the particularly strong junctions connecting the glycocalyx with the cells. The junctions appear as cytoplasmic bundles attached to the dense glycocalyx layer by dint of hemidesmosomes.

New records of spirurid nematodes (Nematoda, Spirurida, Guyanemidae, Philometridae & Cystidicolidae) from marine fishes off New Caledonia, with redescriptions of two species and erection of Ichthyofilaroides n. gen.

Recent examinations of spirurid nematodes (Spirurida) from deep-sea or coral reef marine fishes off New Caledonia, collected in the years 2006–2009, revealed the presence of the following five species: Ichthyofilaroides novaecaledoniensis (Moravec et Justine, 2009) n. gen., n. comb. (transferred from Ichthyofilaria Yamaguti, 1935) (females) (Guyanemidae) from the deep-sea fish Hoplichthys citrinus (Hoplichthyidae, Scorpaeniformes), Philometra sp. (male fourth-stage larva and mature female) (Philometridae) from Epinephelus maculatus (Serranidae, Perciformes), Ascarophis (Dentiascarophis) adioryx Machida, 1981 (female) (Cystidicolidae) from Sargocentron spiniferum (Holocentridae, Beryciformes), Ascarophis (Ascarophis) nasonis Machida, 1981 (males and females) from Naso lituratus and N. unicornis (Acanthuridae, Perciformes), and Ascarophisnema tridentatum Moravec et Justine, 2010 (female) from Gymnocranius grandoculis (Lethrinidae, Perciformes). Two species, I. novaecaledoniensis and A. nasonis, are redescribed based on light microscopical (LM) and scanning electron microscopical (SEM) examinations, the latter used in these species for the first time. Morphological data on the specimen of A. tridentatum from the new host species are provided. Philometra sp. (from E. maculatus) most probably represents a new gonad-infecting species of this genus. The newly established genus Ichthyofilaroides n. gen. is characterized mainly by the presence of a small buccal capsule and by the number and distribution of cephalic papillae in the female; it is the sixth genus in the Guyanemidae.

Diversity of Coomansus zschokkei-group (Nematoda, Mononchida) in Bulgaria

The genus Coomansus Jairajpuri & Khan, 1977 encompasses more than 30 species occuring in various habitats. The Coomansus zschokkei-group, characterized by a posterior position of the dorsal tooth, includes 11 species spread in the northern hemisphere: Europe (3 species), Asia (Far East, Korea, Japan – 8 species), North America (Costa Rica and USA – 1 species), which are reported from subalpine habitats and forests, but also freshwater lakes. So far, one species (C. zschokkei (Menzel, 1914)) was recorded from Bulgaria (Iliev and Ilieva 2019). During this study three undescribed species have been found from mountain areas of Bulgaria. These three closely related Coomansus species were studied using an integrative approach. Based on the dimensions of the buccal capsule and the posterior position of the dorsal tooth they are similar to C. zschokkei, C. cobbi (Eroshenko, 1975), C. mucronatus (Eroshenko, 1975) and C. simenensis (Kreis, 1924), but differ from them by a number of characters such as buccal capsule length, tail length, and lateral piece shape. Coomansus cf. menzeli Loof & Viniszewska-Slipińska, 1993 recovered from moss around birch tree at the Central Balkan Mountain is a new geographical record for Bulgaria. Phylogenetic analyses based on 18S and D2-D3 expansion domains of rRNA genes have been performed for the first time for members of Coomansus zschokkei-group. In both phylogenetic reconstructions, all Coomansus species with the exception of C. gerlachei (De Man, 1904) formed a monophyletic group with very high bootstrap support values. Speciation within the group seems to be related to glaciation and post-glaciation events in mountain areas.

Rhabdias glaurungi sp. nov. (Nematoda: Rhabdiasidae), parasite of Scinax gr. ruber (Laurenti, 1768) (Anura: Hylidae), from the Brazilian Amazon

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

Description of New Species of Coronostrongylus and Dorcopsistrongylus (Strongylida: Chabertiidae) from Dorcopsis muelleri (Macropodidae) from Kumawa Mountains, West Papua, Indonesia

New species of Coronostrongylus and Dorcopsistrongylus (Strongyloidea: Chabertiidae) are described from Dorcopsis muelleri (Macropodidae) from Kumawa Mountains, West Papua, Indonesia. Coronostrongylus hasegawai n.sp .is most similar to C. spearei, the only other species described from New Guinea, in having 24 longitudinal pleats in the buccal cavity and spicules less than 1,400 long. Coronostrongylus hasegawai differs from C. spearei, in a suite of characters including the shape of the cephalic collar, the proportions of the buccal capsule, the disposition of the bursal rays, the length of the spicules and the proportions of the ovejector. Dorcopsistrongylus supriyatnai n.sp differs from all congeners in lacking large anteriorly directed intestinal diverticula. The genus Coronostrongylus is found in Australia and New Guinea while the genus Dorcopsistrongylus appears to be endemic to New Guinea.

A new species of Procamallanus Baylis, 1923 (Nematoda, Camallanidae) from Astronotus ocellatus (Agassiz, 1831) (Perciformes, Cichlidae) in Brazil

A new species ofProcamallanusBaylis, 1923 was found as a parasite of the fishAstronotusocellatus(Agassiz, 1831) from a lake in the Jardim Botânico Bosque Rodrigues Alves, Belém, Brazil.Procamallanusspiculastriatussp. n.has a smooth buccal capsule and a well-developed basal ring that is armed with four sclerotized tooth-like structures. The male of the new species is similar to the two species that are known from Brazilian fish,P.peraccuratusPinto, Fábio, Noronha & Rolas, 1976, andP.annipetteraeKohn & Fernandes, 1988, by the absence of the gubernaculum. It differs from these two by the morphology of the buccal capsule, the number are arrangement of the caudal papillae in males, the size and morphology of the spicules and the shape of the tail of both sexes.Procamallanusspiculastriatussp. n.is the third species discovered in fish from Brazil. This finding extends the geographical distribution of the genus into the Brazilian Amazon.