Observations on some nematodes parasitic in freshwater fishes in Laos

In 1989, samples of some freshwater fishes collected in Vientiane Province (R. Mekong basin) in Laos were examined for helminths. This material comprised 11 species of parasitic nematodes (7 adults and 4 larvae), including 3 species new to science: Camallanus (Camallanus) hampalae sp. n. from Hampala macrolepidota, Procamallanus (Punctocamallanus) punctatus sp. n. from Mystus rhegma and Mystus sp., and Rhabdochona (Globochona) equispiculata sp. n. from Hampala macrolepidota and H. dispar. Zeylanema Yeh, 1960 is considered a subgenus of the genus Camallanus, Dentocamallanus subgen. n. (type species C. (D.) sweeti (Moorthy, 1937)) is proposed for the species of Paracamallanus with teeth in the buccal capsule, and Punctocamallanus subgen. n. (type species P. (P.) punctatus sp. n.) for the species of Procamallanus with the buccal capsule ornamented with punctations. The name Rhabdochona wangi nom. nov. is proposed for R. bagarii Wang et Guo, 1983 (a homonym to R. bagarii Gupta et Srivastava, 1982) and Camallanus gomtii Gupta et Verma, 1978 is newly synonymized with Neocamallanus ophiocephali (Pearse, 1933). All the nematodes are recorded from Laos for the first time. The parasites are briefly described and illustrated and some problems concerning their taxonomy and geographical distribution are discussed.     

Four species of digeneans, including Allocreadium patagonicum sp. n. (Allocreadiidae), from freshwater fishes of Patagonia, Argentina

Four species of adult digeneans are reported from freshwater fishes of two lakes in Neuquén, Patagonia, Argentina. Allocreadium patagonicum sp. n. (Allocreadiidae) is described from the intestine of Percichthys colhuapiensis MacDonagh and Percichthys trucha (Cuvier et Valenciennes) (Percichthyidae) from Lago Aluminé. Three species redescribed are: Acanthostomoides apophalliformis Szidat, 1956 (Acanthostomidae) from the intestine of P. colhuapiensis and P. trucha from Lago Aluminé and of Salmo trutta (Linnaeus) (Salmonidae) from Lago Huechulafquén; Deropegus patagonicus (Szidat, 1956) comb. n. (= Genarches patagonicus Szidat, 1956) (Derogenidae) from the stomach of P. colhuapiensis, P. trucha, Oncorhynchus mykiss (Walbaum) (Salmonidae) and Salvelinus fontinalis (Mitchill) (Salmonidae) from Lago Aluminé and of S. trutta from Lago Huechulafquén; and Austrocreadium papilliferum Szidat, 1956 from the intestine of P. trucha from Lago Aluminé. The genus Polylekithum Arnold, 1934 is considered a synonym of the genus Allocreadium Looss, 1900. The genus Austrocreadium Szidat, 1956 is removed to the family Homalometridae.     

Two species of philometrid nematodes (philometridae) from marine fishes off Japan, including Philometroides branchiostegi sp. n. from Branchiostegus japonicus (malacanthidae)

Gravid females of two species of philometrid nematodes (Philometridae) were collected from marine perciform fishes in Japanese waters, mainly from the southern Sea of Japan. Based on light microscopy and scanning electron microscopy examinations, the previously described but poorly known species Philometra cryptocentri Yamaguti, 1961 is redescribed from specimens recovered from the abdominal cavity of Acanthogobius flavimanus (Temminck et Schlegel), Pterogobius elapoides (Günther) and P. zonoleucus Jordan et Snyder (all Gobiidae) (all new host records); the number (14) and arrangement of cephalic papillae in this species are described for the first time. The new species, Philometroides branchiostegi sp. n. from head tissues of Branchiostegus japonicus (Houttuyn) (Malacanthidae), based on a single specimen, is mainly characterized by the embossment of the entire body except for the cephalic end, presence of four submedian pairs of large cephalic papillae of external circle and two small lateral single papillae of internal circle, pair of large papilla-like caudal projections, the oesophagus with a distinct anterior inflation, by a markedly small body (length about 18 mm) and the larvae 306-465 microm long.     

Two new nematode species, Paragendria papuanensis sp. n. (Seuratoidea) and Rhabdochona papuanensis sp. n. (Thelazioidea), from freshwater fishes in Papua New Guinea

Two new nematode species, Paragendria papuanensis sp. n. (Quimperiidae) and Rhabdochona papuanensis sp. n. (Rhabdochonidae), are described from the intestine of freshwater fishes Glossamia giellerupi (Weber et Beaufort) (Apogonidae) and Melanotaenia affinis (Weber) (Melanotaeniidae), respectively, from the Sogeram River (Ramu River basin), Madang Province, northern Papua New Guinea. The former species is characterized mainly by the absence of oesophageal teeth, the presence of conspicuously inflated papillae of the last two subventral pairs, a gubernaculum, spicules 69-75 microm long, eggs measuring 57-66 x 39-45 microm, and by a small body (male and female 3.2-3.7 and 5.8 mm long, respectively). Paragendria is considered a valid genus, to which P. aori (Khan et Yaseen, 1969) comb. n., P. guptai (Gupta et Masoodi, 2000) comb. n., P. hanumanthai (Gupta et Jaiswal, 1988) comb. n. and P. vermae (Gupta et Masoodi, 2000) comb. n. are newly transferred. Rhabdochona papuanensis differs from all congeners mainly in having hammer-shaped deirids and from individual species also in other characters. Both findings represent the first records of species of Paragendria and Rhabdochona from the Australian zoogeographical region and the first records of the representatives of these genera from fishes of the families Apogonidae and Melanotaeniidae, respectively.     

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).     

A new atractid nematode,Atractis vidali sp. n. (Nematoda: Atractidae), from cichlid fishes in southern Mexico

A new nematode species, Atractis vidali sp. n., is described from the intestine of cichlid fishes, Vieja intermedia (Günther) (type host) and Cichlasoma pearsei (Hubbs), from specimens collected in three localities in the Mexican states of Campeche (Santa Gertrudis Creek) and Chiapas (Cedros and Lacanjá Rivers). It differs from the only other atractid species reported in fishes of Mexico, Atractis bravoae, mainly in possessing two very unequal spicules. In contrast to the 10 species parasitising amphibians and reptiles in America, the new species has a longer body, spicules and a gubernaculum, and a different distribution of the caudal papillae. This is the second species of the genus Atractis recorded from freshwater fishes.     

Two new nematodes,Paraseuratoides ophisterni gen. et sp. n. (Quimperiidae) and Philometra ophisterni sp. n. (Philometridae), from the swamp-eel Ophisternon aenigmaticum in Mexico

Two new nematodes, Paraseuratoides ophisterni gen. et sp. n. (Seuratoidea: Quimperiidae) and Philometra ophisterni sp. n. (Dracunculoidea: Philometridae) are described based on specimens recovered from the intestine and mesentery, respectively, of the swamp-eel Ophisternon aenigmaticum Rosen et Greenwood (Synbranchiformes: Synbranchidae) from a canal of the Papaloapan River in Tlacotalpan, State of Veracruz, Mexico. The genus Paraseuratoides is mot similar to Paraseuratum Johnston et Mawson, 1940, differing from it mainly in the absence of a bulbous inflation on the anterior end of the oesophagus and in the structure of the mouth (presence of 6 spines in addition to 6 oesophageal teeth). Neoquimperia Wang, Zhao, Wang et Zhang, 1979 and Wuinema Yu et Wang, 1992 are synonymised with Ezonema Boyce, 1971 and Paragendria Baylis, 1939, respectively, and Haplonema hamulatum Moulton, 1931 is considered a junior synonym of Ichthyobronema conoura Gnedina et Savina, 1930. Philometra ophisterni (only females) is mainly characterised by minute cephalic papillae, a greatly developed anterior oesophageal bulb separated from the cylindrical part of the oesophagus, anterior extension of the oesophageal gland anterior to the nerve ring, and by the character of large caudal projections. This is the first Philometra species recorded from inland fishes in Mexico.     

Some nematodes and acanthocephalans from exotic ornamental freshwater fishes imported into Germany

Five species of adult nematodes, unidentifiable nematode larvae, and three species of acanthocephalans, were found in freshwater ornamental fishes newly imported into Germany from Brazil, Colombia, Indonesia, Malaysia, Nigeria, Peru, Sri Lanka and Thailand. The following species were identified: Adult Nematoda: Pseudocapillaria tomentosa, Capillariidae gen. sp., Dichelyne hartwichi sp. n., Procamallanus (Spirocamallanus) pintoi and Spinitectus allaeri; Acanthocephala: Pseudogorgorhynchus arii gen. et sp. n., Neoechinorhynchus sp. and Pallisentis sp. The nematode Dichelyne hartwichi sp. n. (male only) from the intestine of Chelonodon fluviatilis (Hamilton) from Thailand is characterised mainly by the presence of minute cuticular spines on the tail tip, length of spicules (510 microns) and arrangement of caudal papillae. The acanthocephalan Pseudogorgorhynchus arii sp. n. from the intestine of Ariopsis seemanni (Günther) from Colombia represents a new genus Pseudogorgorhynchus gen. n., differing from other genera of the Rhadinorhynchidae mainly in possessing a small proboscis armed with markedly few (18) hooks arranged in six spiral rows. Spinitectus macheirus Boomker et Puylaert, 1994 and Spinitectus moraveci Boomker et Puylaert, 1994 are considered junior synonyms of Spinitectus allaeri Campana-Rouget, 1961.     

Monogeneans of freshwater fishes from cenotes (sinkholes) of the Yucatan Peninsula, Mexico

During a survey of the parasites of freshwater fishes from cenotes (sinkholes) of the Yucatan Peninsula the following species of monogeneans were found on cichlid, pimelodid, characid and poeciliid fishes: Sciadicleithrum mexicanum Kritsky, Vidal-Martinez et Rodriguez-Canul, 1994 from Cichlasoma urophthalmus (Günther) (type host), Cichlasoma friedrichsthali (Heckel), Cichlasoma octofasciatum (Regan), and Cichlasoma synspilum Hubbs, all new host records; Sciadicleithrum meekii Mendoza-Franco, Scholz et Vidal-Martínez, 1997 from Cichlasoma meeki (Brind); Urocleidoides chavarriai (Price, 1938) and Urocleidoides travassosi (Price, 1938) from Rhamdia guatemalensis (Günther); Urocleidoides costaricensis (Price et Bussing, 1967), Urocleidoides heteroancistrium (Price et Bussing, 1968), Urocleidoides anops Kritsky et Thatcher, 1974, Anacanthocotyle anacanthocotyle Kritsky et Fritts, 1970, and Gyrodactylus neotropicalis Kritsky et Fritts, 1970 from Astyanax fasciatus; and Gyrodactylus sp. from Gambusia yucatana Regan. Urocleidoides chavarriai, U. travassosi, U. costaricensis, U. heteroancistrium, U. anops, Anacanthocotyle anacanthocotyle and Gyrodactylus neotropicalis are reported from North America (Mexico) for the first time. These findings support the idea about the dispersion of freshwater fishes and their monogenean parasites from South America through Central America to southeastern Mexico, following the emergence of the Panamanian isthmus between 2 and 5 million years ago.     

New oxyuroid nematodes of the genera Ichthyouris and Spinoxyuris from South American freshwater fishes

Three hitherto unknown oxyuroid nematode species of the family Pharyngodonidae are described from the intestine of South American freshwater fishes, two of them being established as species new to science: Spinoxyuris annulata sp. n. from Myleus ternetzi (Norman) (Serrasalmidae) from French Guiana (Sinnamary River) and Ichthyouris ovifilamentosa sp. n. from Cichlasoma sp. (Cichlidae) from Amazonas (Negro River, S?o Gabriel da Cachoeira), Brazil. A third species, recovered from the same host as the latter (Cichlasoma sp.), was identified only as Ichthyouris sp. because of the absence of the male, although it probably also represents a new species. S. annulata differs from the only other congeneric species, S. oxydoras Petter, 1994, mainly in the absence of egg filaments, the location of an unpaired postanal papilla in the male, a distinctly longer spicule, and in an approximately double length of the body. Ichthyouris ovifilamentosa is closest to I. ro Inglis, 1962, differing from it principally in the structure of the cephalic end, the position of the excretory pore, and in the presence of filamented eggs. Ichthyouris sp. females differ from their congeners mainly in a characteristic structure of the cephalic end, the extent of lateral alae and the shape of their posterior ends, and in the character of egg filaments.     

Three interesting nematodes from the fish Parupeneus indicus (Mullidae, Perciformes) of the Indian Ocean, including a new species, Ascarophis parupenei sp. n. (Habronematoidea)

In 1986, samples of the marine commercial fish Parupeneus indicus originating from the Indian Ocean near Somalia were examined for helminths. They proved to harbour three species of adult parasitic nematodes: Ascarophis parupenei sp. n., Philometra lateolabracis (Yamaguti, 1935), and Cucullanus himezi Yamaguti, 1941. A. parupenei sp. n. is characterized mainly by its non-filamented eggs with a fine flock-like coating, length ratio (1: 13-16) of the muscular and glandular parts of oesophagus, length of spicules (0.533-0.600 mm and 0.150-0.171 mm), structure of the head end and shape of the female tail. All these species are briefly described and illustrated and some problems concerning their taxonomy and geographical distribution are discussed.     

Philometrid nematodes infecting fishes from the Everglades National Park, Florida, U.S.A

The following three species of the Philometridae (Nematoda: Dracunculoidea) are described from marine perciform fishes of the Everglades National Park (northern Gulf of Mexico), Florida, U.S.A.: Philometra brevispicula sp. n. (male and females) from the subcutaneous tissue of mouth of the gray snapper Lutjanus griseus (Linnaeus) (Lutjanidae), Philometroides grandipapillatus sp. n. (only females) from pectoral fin muscle of the crevalle jack Caranx hippos (Linnaeus) (Carangidae), and Caranginema americanum Moravec, Montoya-Mendoza et Salgado-Maldonado, 2008 (females) from the subcutaneous fascia of trunk muscle in crevalle jack C. hippos. Philometra brevispicula is mainly characterized by small cephalic papillae of the external circle, the absence of oesophageal teeth and the presence of small caudal projections in gravid female, markedly short spicules (45 microm) in male, and by its location in the host. Philometroides grandipapillatus differs from congeners mainly in the shape of the cephalic region (narrow, conspicuously protruding), large cephalic papillae of the external circle and the absence of caudal projections in female, and by the site of infection in the host. Caranginema americanum is for the first time recorded from the northern Gulf of Mexico.     

A new Huffmanela species, H. schouteni sp. n. (Nematoda: Trichosomoididae) from flying fishes in Cura?ao

A new nematode species, Huffmanela schouteni sp. n., has been established on the basis of its egg morphology and biological characters (adult nematodes are unknown). The dark-shelled eggs of this histozoic parasite occur in masses in the abdominal cavity, serose covers of internal organs and in the liver of the flying fishes Hirundichthys affinis Günther (type host) and Cypselurus cyanopterus Cuvier et Valenciennes in Cura?ao. The eggs of H. schouteni sp. n. differ from those in other congeneric species mainly in the absence of small spines on the surface of the transparent envelope enclosing the egg proper, measurements (size of eggs 0.069-0.075 x 0.027-0.030 mm) and their localization in the host. A key to Huffmanela species based on egg morphology has been provided.     

Observations on the morphology of the hair follicle mites (Acari: Demodicidae) from Cervus elaphus L., 1758 including description of Demodex acutipes sp. n

Morphology of Demodex acutipes sp. n. and Demodex sp. parasitizing the red deer, Cervus elaphus L., 1758 is described and diagnostic characters of three Demodex species from this host are compared.     

Neoechinorhynchus (Neoechinorhynchus) zabensis sp. n. (Acanthocephala: Neoechinorhynchidae) from freshwater fish in northern Iraq

Neoechinorhynchus (Neoechinorhynchus) zabensis sp. n. (Acanthocephala: Neoechinorhynchidae) is described from Capoeta damascina (Valenciennes, 1842) (type host) and Capoeta trutta (Heckel, 1843) in the Greater and Lesser Zab Rivers, northern Iraq. The new species is unique among all other species of the genus by its characteristic paired para-vaginal muscular appendage and fragmented giant nuclei in the lemnisci. Eleven of the other 88 valid species of Neoechinorhynchus and N. zabensis have middle and posterior hooks of equal length. However, N. zabensis is distinguished from the others by size of trunk, proboscis, proboscis hooks and lemnisci, number of giant nuclei, position of female gonopore, and geographical and host distribution. It is also distinguished from six other species of Neoechinorhynchus previously reported from Iraq. Other distinguishing features are also included.     

Myxozoans infecting the sharptooth catfish, Clarias gariepinus in the Okavango River and Delta, Botswana, including descriptions of two new species, Henneguya samochimensis sp. n. and Myxobolus gariepinus sp. n

During a recent investigation of parasites infecting fishes from the Okavango River and Delta, Botswana (southern Africa) fourteen sharptooth catfish, Clarias gariepinus (Burchell, 1822) (Siluriformes: Clariidae) were examined for the presence of myxozoan infections. Results revealed the presence of two species of the genus Henneguya Thélohan, 1895 and one species of the genus Myxobolus Bütschli, 1882 infecting this fish host. Two of the sampled fish exhibited large plasmodia of Henneguya suprabranchiae Landsberg, 1987 in the cartilage of the accessory breathing organ, another two individuals were infected with H. samochimensis sp. n. plasmodia in the gills and another three individuals revealed an infection with Myxobolus gariepinus sp. n. plasmodia in the ovaries.     

Monostephanostomum nolani sp. n. and M. krusei Reimer, 1983 (Digenea: Acanthocolpidae) from carangid fishes from coral reef waters off Australia

Monostephanostonum nolani sp. n. is described from Carangoides plagiotaenia Bleeker, off Lizard Island, Great Barrier Reef, Queensland, Australia. It differs from all other species in the genus except M. manteri Kruse, 1979 in that the vitellarium reaches into the forebody. It differs from M. manteri in the ventral hiatus in the circum-oral spine row, the extent of the vitellarium in the forebody, where it is not confluent, its elongate pharynx and its smaller eggs. Monostephanostoinum krusei Reimer, 1983 is redescribed from Pseudocaranx dentex (Bloch et Schneider) from Ningaloo Reef off Western Australia. It is considered similar to M. nolani, differing in the vitellarium being restricted to the hindbody, but sharing with M. nolani an unusual arrangement of small body-spines on the antero-ventral surface. It is also morphologically very similar to Monostephanostomum roytmani (Parukhin, 1974), which apparently lacks the diminutive antero-ventral body-spines. A key to eight recognized species in the genus is presented.     

Revision of Dioncopseudobenedenia Yamaguti, 1965 including the description of D. ancoralis sp. n. (Monogenea: Capsalidae) from Pacific acanthuroid teleosts

Dioncopseudobenedenia Yamaguti, 1965 (Monogenea: Capsalidae) is redefined. Dioncopseudobenedenia kala Yamaguti, 1965 (type species) is redescribed from type material from Hawaii and from new specimens from Heron Island, Queensland, Australia and New Caledonia. We made detailed observations on D. macracantha Yamaguti, 1968 from type material from Hawaii, and from new material from Heron Island and New Caledonia. Dioncopseudobenedenia ancoralis sp. n. is described from the gill chamber of Siganus lineatus (Valenciennes) from Green Island and Heron Island, Australia and from New Caledonia. This study confirms that only one pair of large central sclerites is present on the haptor in Dioncopseudobenedenia species. The male copulatory organ in species of Dioncopseudobenedenia is a penis contained in a fluid-filled space (= penis canal) with weakly muscular walls. Dioncopseudobenedenia kala and D. ancoralis bear a sclerite at the tip of the penis. In D. macracantha, the structure of the penis, which has no terminal sclerite, indicates it may combine the functions of a penis and a cirrus. Dioncopseudobenedenia is compared with Calicobenedenia Kritsky et Fennessy, 1999, the other capsalid genus with a single pair of large sclerites on the haptor. The large haptoral sclerites in species of Dioncopseudobenedenia resemble accessory sclerites, whereas those of C. polyprioni Kritsky et Fennessy, 1999 resemble hamuli. Observations of oncomiracidia confirmed that the large haptoral sclerites in D. kala are accessory sclerites. Haptoral morphology suggests that different Dioncopseudobenedenia spp. employ different means of attachment. Mating behaviour was observed twice between two different pairs of D. kala specimens from Heron Island. Two preserved specimens from Nouméa, New Caledonia had structures near the dorsal vaginal pore that we interpret as spermatophores. This is the first report of spermatophores in a capsalid inhabiting the gill chamber. The geographic distribution of Dioncopseudobenedenia spp. is discussed.