Structure of the female cephalic end and cuticular ornamentations of Paraphilometroides nemipteri (Nematoda:Philometridae), as revealed by SEM

Scanning electron microscopy (SEM) examination of a paratype specimen (gravid female) of the philometrid nematode Paraphilometroides nemipteri Moravec et Shaharom-Harrison, 1989, the type species of Paraphilometroides Moravec et Shaharom-Harrison, 1989, made it possible to recognise the true structure of the cephalic end and the shape of cuticular ornamentations on the body. In contrast to other philometrid genera, the cephalic end is angular in lateral view and rounded in dorsoventral view; large external cephalic papillae are fused together to form a marked dorsal and a ventral ala, each bent into a curve; six minute internal papillae, including a pair of previously not reported lateral papillae, were found; amphids were indistinct. Cuticular ornamentations (inflations) were found to be transversely elongated. These features, especially the unique cephalic structure, clearly distinguish Paraphilometroides from other philometrids and confirm the validity of this genus. Moravec and Shaharom-Harrison (1989) erected the hitherto monotypic philometrid genus Paraphilometroides Moravec et Shaharom-Harrison, 1989 with the type species P. Nemipteri Moravec et Shaharom-Harrison, 1989, described from females found in the fins and operculum of the marine fish (notchedfin threadfin bream) Nemipterusperonii (Valenciennes) from off the South China Sea coast, Malaysia. The male of P. nemipteri remains unknown. The authors distinguished Paraphilometroides from the related genus Philometroides Yamaguti, 1935 mainly by the unusual structure of the female cephalic end, which is unique within the family Philometridae (see Moravec 2006). However, P. nemipteri was studied only by light microscopy (LM), whereas some details of the cephalic structure, especially the cephalic papillae of gravid philometrid females are usually difficult to observe by LM due to a various degree of their reduction and atrophy (Moravec 2004); in the past, some philometrid species were even reported to have no cephalic papillae. Consequently, the only reliable method to study the cephalic structures in philometrids is the use of scanning electron microscopy (SEM). Therefore, one of the ethanol-preserved paratype specimens (gravid female) of P. nemipteri, deposited in the Helminthologi-cal Collection of the Institute of Parasitology, Biology Centre     

Development of Spinitectus inermis (Nematoda: Cystidicolidae), a parasite of eel,Anguilla anguilla,in Europe

The development of the nematode Spinitectus inermis (Zeder, 1800), a parasite of the stomach of eels, Anguilla anguilla (L.) in Europe, was experimentally studied. Mayfly nymphs Caenis macrura, Ecdyonurus dispar, Heptagenia sulphurea, Potamanthus luteus and Seratella ignita from Portugal and the Czech Republic were found to serve as experimental intermediate hosts. After ingestion of the nematode eggs by the mayfly nymphs, the toothed first-stage larvae were released and penetrated into the body cavity of the intermediate host. There they moulted twice (on day 4 and 6 post infection [p.i.] at water temperatures of 20-25 degrees C), attaining the third infective stage. The definitive host, A. anguilla, undoubtedly acquires infection by feeding on mayfly nymphs harbouring infective-stage larvae. In an experimentally infected eel, the fourth-stage larva undergoing the third moult was observed 28 days p.i. at water temperature of 20 degrees C. The larval stages, including moulting forms, are described and illustrated. The prepatent period of S. inermis is estimated to be about two months.     

Redescription of Metabronema magnum (Nematoda: Cystidicolidae), a swimbladder parasite of the carangid fish Gnathanodon speciosus off New Caledonia

The cystidicolid nematode Metabronema magnum (Taylor, 1925) is redescribed from specimens collected from the swimbladder of the fish (golden trevally) Gnathanodon speciosus (Forssk?l) (Carangidae, Perciformes) off New Caledonia, South Pacific (a new geographical record). The light and scanning electron microscopical examination made it possible to study in detail the morphology of this so far little-known species. Its pseudolabia were found to possess distinct anterior protrusions (protuberances), sublabia are absent, only four cephalic papillae are present, deirids are bifurcated, and the male possesses six pairs of postanal papillae. By its morphology, M. magnum seems to be most similar to species of Salvelinema Trofimenko, 1962, also from the swimbladder of fishes, differing from them mainly in the presence of median wedge-shaped outgrowths in the mouth, lateral alae, the longer spicule on the right side, and a fewer number of pairs of preanal papillae in the male. Since the morphology of M. magnum considerably differs from that of other representatives of the Cystidicolidae, Metabronema in Rasheed's (1966) conception is considered a valid genus.     

External morphological differences between Crepidostomum farionis and Crepidostomum metoecus (Trematoda: Allocreadiidae), parasites of salmonids,as revealed by SEM

Scanning electron microscopy examinations of trematode specimens belonging to Crepidostomum farionis (O.F. Muller, 1784) and C. metoecus Braun, 1900, collected from brown trout, Salmo trutta fario L., in the Czech Republic, made it possible to study their surface morphology including details not described previously. The tegument of both species bears numerous characteristic papillae around the oral sucker (in C. metoecus also around the ventral sucker) and the ventral and dorsal surfaces of the forebody, exhibiting a high degree of variability in numbers and arrangement, with tegumental bosses forming lateral fields on the forebody and minute sensory receptors with submerged cilia scattered on the surface of the dorsal part of the oral sucker. In addition to marked differences in the size, shape and position of the oral muscular lobes, both species distinctly differ in the number of genital pores: two separate pores in C. farionis and a single pore in C. metoecus.     

Data on the morphology of the nematode Spinitectus minor (Stewart, 1914) (Nematoda: Cystidicolidae)

Morphology of the nematode Spinitectus minor harboured by Mastacembelus armatus from Burdwan, West Bengal, India was studied by light and scanning electron microscopes. The worms were described, illustrated and discussed taking into consideration of the information available relative to this species. Alate spicules, polar caps on the eggs and prodelphic uteri are clearly seen in the present LM studies and SEM photomicrographs provided detailed information about the microtopography of the worms.     

Moravecnema segonzaci gen. et sp. n. (Nematoda: Cystidicolidae) from Pachycara thermophilum (Zoarcidae), a deep-sea hydrothermal vent fish from the Mid-Atlantic Ridge

A new cystidicolid nematode, Moravecnema segonzaci gen. et sp. n. is described from the intestine of the teleost fish Pachycara thermophilum Geistdoerfer (Zoarcidae) from the hydrothermal sites Logatchev and Snake Pit-Moose of the Mid-Atlantic Ridge, at depths of 3,008; 3,492, and 3,510 m. The new genus Moravecnema is characterised by a dorsoventrally elongated oral opening, rudimentary pseudolabia, and four pairs of precloacal and six pairs of postcloacal caudal papillae in the male. The species has two spicules of unequal length, about 330 and 80 microm long. Males are about 5 mm and females about 5-10 mm long. Eggs have long thin polar filaments. This is the first species of parasitic nematode described from a fish endemic to hydrothermal deep-sea vents.     

A new species of Neoascarophis (Nematoda: Cystidicolidae) parasitic in Mullus argentinae (Perciformes: Mullidae) from the Atlantic coast of South America

A new nematode species (Neoascarophis mariae n. sp.) is described based on specimens collected from the Argentine goatfish Mullus argentinae (Hubbs et Marini) from coastal waters off the state of Rio de Janeiro, Brazil. In the genus, the new species belongs to the group of species with females that have the vulva near the posterior end of the body. Only males of Neoascarophis longispicula Moravec et Klimpel, 2009 are known and can be distinguished from those of the new species by their larger body, developed and somewhat dorsoventrally expanded flat inner part of the pseudolabia, bifurcate deirids and larger spicules (the left one with a rounded tip) with a different length ratio. Other species with females that have the vulva near the equatorial region are N. yarihige Machida, 1976 and N. bathygadi Machida, 1976. Both males and females of N. yarihige are longer than those of the new species and have a shorter vestibule; males have shorter spicules with a different length ratio. Neoascarophis bathygadi is the only member of the genus that shares the presence of a cephalic vesicle with the new species, which, however, is shorter and arises at 40 microm from the anterior end instead from the deirids, as in the new species. Both males and females of N. bathygadi are also longer than those of the new species and have a shorter vestibule; males have a larger left spicule, but shorter right spicule and a different length ratio. Ascarophis upeneichthys Johnston et Mawson, 1945, a parasite ofa mullid host, is transferred to Neoascarophis Machida, 1976 and is distinguished from the new species by having a shorter vestibule in females and shorter spicules (left spicule with a pointed tip) with a different length ratio in males.     

Rhabdochona mexicana sp. n. (Nematoda: Rhabdochonidae) from the intestine of characid fishes in Mexico

A new nematode, Rhabdochona mexicana sp. n., is described based on specimens recovered from the intestine of two species of fishes, Astyanax mexicanus (De Filippi) (type host) and Astyanax fasciatus (Cuvier) (Characidae: Characiformes) in central Mexico. This species is characterised by the following characters: 10 anteriorly directed teeth in the prostom, a larger (left) spicule which is slender in form with a small bifurcation at its distal tip covered by a cuticular membrane, a smaller (right) spicule without a barb at its distal tip, eggs bearing an irregular flock-like coating, and a conical tail without a cuticular spike (in both sexes).     

New data on the morphology and systematic status of Spinitectus petrowi and Spinitectus gigi (Nematoda: Cystidicolidae) parasitic in catfishes in central China

Two little-known nematode species of the genus Spinitectus Fourment, 1883, S. petrowi Belous, 1965 (prevalence 25%, intensity 1-8) and S. gigi Fujita, 1927 (prevalence 10%, intensity 2-3), were collected from the gastrointestinal tract of the yellow catfish, Pelteobagrus fulvidraco (Richardson), from Liangzihu Lake, Hubei Province, central China, in September of 2002. The light and scanning electron microscopical examination of this material, supplemented by a few museum specimens of S. gigi collected from the catfish Clariasfuscus (Lacépède) in southern China, made it possible to study in detail the morphology of these parasite species and to redescribe them. The first species, whose correct name is S. petrowi Belous, 1965, exhibits some morphological features (e.g., unusually short vestibule, shape of pseudolabia and of the left spicule) not found in most other congeners; a unique feature is the presence of peculiar pairs of transversely oriented peg-like cuticular spines with rounded ends on the ventral surface of the female tail. Spinitectus gigi was found to have 28-31 cuticular spines in the first ring, relatively long distances between the 2nd-7th rings of spines, and anterior rings divided into 2 sectors; the excretory pore is located at the level of the 4th ring of cuticular spines; males posses 4 pairs of preanal- and 6 pairs of postanal caudal papillae and a pair of small phasmids. Spinitectus bagri Wang, Wu et Yu, 1993 and S. wulingensis Yu et Wang, 1997 are considered junior synonyms of S. petrowi, whereas S. clariasi Ky, 1971, S. ophicephali Ky, 1971 and S. yuanjiangensis Wang, Wu et Yu, 1997 are regarded to be junior synonyms of S. gigi. Spinitectus petrowi was not previously reported from China.     

Intraspecific Variation in isolates of Bursaphelenchus xylophilus (Nematoda: Aphelenchoididae) revealed by ISSR and RAPD fingerprints

Journal of Plant Diseases and Protection - The pinewood nematode Bursaphelenchus xylophilus is the causal agent of pine wilt disease. In order to trace the origin of its recently introduced...     

New morphological data on the first-stage larvae of two Procamallanus species (Nematoda: Camallanidae) based on SEM studies

First-stage larvae of camallanid nematodes Procamallanus (Procamallanus) laeviconchus (Wedl, 1862) and Procamallanus (Procamallanus) sp. from naturally infected Distichodus niloticus (Hasselquist) and Clarias gariepinus (Burchell), respectively, from Lake Turkana, Kenya (new geographical records) are described, being for the first time studied by scanning electron microscopy. Larvae of both species are characterised by the presence of a dorsal cephalic tooth, four submedian cephalic papillae and a pair of amphids, and by the elongate tail with several terminal digit-like processes. The latter formations probably serve for the attachment of larvae to the substrate in water when the larvae attract copepod intermediate hosts by their movements; these structures, especially their numbers, may be of taxonomic importance in camallanid nematodes.     

Camallanus cotti (Nematoda: Camallanidae), an introduced parasite of fishes in New Caledonia

A pathogenic Asian nematode species of Camallanus, C. cotti Fujita, 1927, was found in New Caledonia, South Pacific, for the first time; it was recorded from two native fishes, Awaous guamensis (Valenciennes) (Gobiidae) (prevalence 51%, intensity 1-25) and Kuhlia marginata (Cuvier) (Kuhliidae) (a single specimen found), of the La Foa River, about 100 km north of Nouméa; the latter represents a new host record. Morphological data on C. cotti based on New Caledonian specimens and those previously collected from aquarium-kept Misgurnus anguillicaudatus (Cantor) in Canada have been provided. The SEM examination of C. cotti, applied for the first time in this species, made it possible to study some of its morphological details; first-stage larvae from the female's uterus were found to possess several digit-like processes on the tail tip, not previously reported for any species of the Camallanidae. Camallanus moraveci Petter, Cassone et France, 1974 is considered a junior synonym of C. cotti. A list of hitherto recorded hosts of C. cotti is provided. Camallanus cotti is assumed to be introduced into New Caledonia along with the introduction of the exotic poeciliid fishes, which are known to be among the most common hosts of C. cotti in aquarium cultures worldwide.     

Development of Procamallanus saccobranchi (Nematoda: Camallanidae), a parasite of a freshwater fish in India

The development of the nematode Procamallanus saccobranchi Karve, 1952, a parasite in the stomach of the fish Heteropneustes fossilis (Bloch), was studied in Mesocyclops crassus (Fischer) and Mesocyclops leuckarti (Claus). After being ingested by the copepods the nematode first-stage larvae penetrated into the haemocoel of the intermediate host; there they moulted twice (on days 3 and 5 p.i. at 28-30 degrees C) attaining the third, infective stage. The definitive host H. fossilis acquired infection by feeding on copepods harbouring infective-stage larvae; in the stomach of this definitive host, the larvae were observed to undergo two more moults. The third moult occurred on day 13 p.i. and the fourth moult on day 38 p.i. and day 66 p.i. in "male" and "female" larvae, respectively. The larval stages, including the moulting forms are described and illustrated.     

Morphological and molecular characterisation of Trichodorus golestanensis (Nematoda: Trichodoridae), a new species from Iran

Several species of trichodorid nematodes cause economically important disease on plants. Trichodorus comprises most of the trichodorid species. Trichodorus golestanensis n. sp. is described from a forest park in northern Iran. The new species belongs to the T. lusitanicus morpho-species group and is characterized in male by three ventromedian cervical papillae of which two at level of onchiostyle region, three ventromedian precloacal supplements, the posterior one just anterior to retracted spicules and ventrally curved spicules with mid-blade indentation provided with a few bristles. Females are distinguished by well developed triangular vaginal sclerotized pieces in lateral optical view, a rhomboid-shaped vagina and a transverse slit-like vulva in ventral view. Molecular analysis using the sequence of D2-D3 expansion segment of 28S rDNA differentiated the new species and confirmed the relationships of T. golestanensis n. sp. with T. andalusicus and T. asturanus. The sequences of D2-D3 regions were also provided for previous trichodorid records from Iran T. gilanensis, P. teres and N. minor together with discussion of their relationship.     

Hysterothylacium winteri sp. n. (Nematoda: Anisakidae), a parasite of Chilean rock cod, Eleginops maclovinus (Perciformes: Eleginopidae), from South Chile

Hysterothylacium winteri sp. n. (Nematoda: Anisakidae) was collected from the intestine of a marine-estuarine fish, Eleginops maclovinus (Valenciennes) (Perciformes: Eleginopsidae), from Abtao in the Gulf of Ancud, Chile. Sixteen (51.6%) out of 31 fish were infected; the intensity was 1-10 (mean 4) worms/host. The new species belongs to the group of congeners possessing one double pair of postanal papillae. By possessing a lateral pair of phasmids situated near the tip of tail, H. winteri most closely resembles Hysterothylacium habena. The new species can be distinguished by the lip flanges forming broadly rounded points and the equal, short spicules (320-400 microm long) representing 0.9-1.7% of body length.     

Punctodera achalensis n. sp. (Nematoda: Punctoderidae), a new cyst nematode from Argentina

European Journal of Plant Pathology - Trichoderma aggressivum, a mycopathogen causing green mould disease, is a major problem in Agaricus bisporus cultivation due to crop loss, and resistance to...     

Rhabdochona minima sp. n. (Nematoda: Spiruroidea) from the loach, Noemacheilus inglisi (Hora), of Nepal.

A new nematode species, Rhabdochona minima sp.n., is described from the intestine of Noemacheilus inglisi (HORA) OF Nepal (River Ganges drainage system). Characteristics features of this species (only males were found) are the small size of body, size and type of spicules, shape of tail and arrangement of caudal papillae. On the basis of its morphology, R. minima sp.n. belongs to the subgenus Globochona sensu Moravec, 1975. The species Rhabdochona cavasius Rehana et Bilqees, 1973 is considered to be a synonym of R. mazedi Prassad et Sahay, 1965.     

Redescription of Dracunculus globocephalus Mackin, 1927 (Nematoda: Dracunculidae), a parasite of the snapping turtle, Chelydra serpentina

Dracunculus globocephalus Mackin, 1927 (Nematoda: Dracunculoidea) is redescribed from specimens collected from the mesentery of the snapping turtle, Chelydra serpentina (L.), in Louisiana, USA. The use of scanning electron microscopy, applied for the first time in this species, made it possible to study details in the structure of the cephalic end and the arrangement of male caudal papillae that are difficult to observe under the light microscope. This species markedly differs from all other species of Dracunculus in having the spicules greatly unequal in size and shape, in the absence of a gubernaculum, and in the disposition of male caudal papillae. The validity of D. globocephalus is confirmed, but the above mentioned morphological differences are not sufficient for listing it in a separate genus. This is the first record of D. globocephalus in Louisiana.