The nematode Goezia spinulosa (Diesing, 1839) (Raphidascarididae) is redescribed based on specimens found in the stomach and intestine of the naturally infected arapaima Arapaima gigas (Schinz) from the Mexiana Island, Amazon River Delta, Brazil. Light and electron microscopy examinations revealed some previously unreported or inaccurately described morphological features in the species, such as the position of the excretory pore, phasmids in the male or the number (4) of postanal papillae. The morphology of G. spinulosa is compared with that of other four congeneric species parasitizing freshwater fishes in South America. This nematode seems to be one of the most pathogenic parasites of A. gigas in the Mexiana Island, which are responsible for a high mortality of cultured arapaima fingerlings. Apparently, the source of G. spinulosa infection for arapaima fingerlings cultured in tanks was the infected plankton collected in the localities inhabited by wild arapaimas. Therefore, control measures should include the sterilisation of the plankton before its use as food for fish. A rare infection of Eustrongylides sp. larvae (Dioctophymatidae) in arapaima fingerlings was also found (new host record); the larvae were inside swellings on the body surface.
Based on light and scanning electron microscopical studies, the following five gonad-infecting species of the Philometridae (Nematoda: Dracunculoidea) are described from marine perciform fishes off the eastern coast of India (Bay of Bengal): Philometra sphyraenae sp. n. (males and females) from the pickhandle barracuda Sphyraena jello Cuvier (Sphyraenidae), Philometra gerrei sp. n. (males and females) from the whipfin silver-biddy Gerres filamentosus Cuvier (Gerreidae), Philometra otolithi sp. n. (single female) from the tigertooth croaker Otolithes ruber (Bloch et Schneider) (Sciaenidae), Philometra sp. (females) from the Belanger's croaker Johnius belangerii (Cuvier) (Sciaenidae), and Philometroides eleutheronemae sp. n. (females) from the fourfinger threadfin Eleutheronema tetradactylum (Shaw) (Polynemidae). All new species are distinguished from their congeners parasitizing gonads of marine fishes by morphological (mainly the gubernaculum structure in males and the shape and structure of the cephalic and caudal ends and of the oesophagus in females) and biometrical features. Philometra rajani Mukherjee, 1963 is considered a species inquirenda.
A new nematode species, Guyanema longispiculum sp. n. is described from the abdominal cavity of the freshwater armoured catfish, Loricariichthys hrunneus (Hancock), from two localities in western Venezuela. It differs from all hitherto known members of the genus in having unusually long spicules (0.480-0.609 mm) and from individual species also by other morphological and biometrical features. It is characterized by the presence of eight cephalic papillae arranged in two circlets, localization of deirids anterior to the nerve ring, a conical, undivided tip of the tail in both sexes, four pairs of preanal and six pairs of postanal papillae in the male, and a markedly elevated vulva in the female. A key to species of Guyanema is presented.
The present paper comprises a systematic survey of helminths from 202 red groupers, Epinephelus morio (Valenciennes) (Pisces: Serranidae), the most important commercial marine fish in the region, collected from ten localities off the Yucatan Peninsula in the Gulf of Mexico during 1994-1996; two more helminth species were recorded from E. morio earlier. Thirty species of helminths were found: Monogenea 1, Cestoda 3, Trematoda 17, Nematoda 8, Acanthocephala 1. Of them, 15 species were adults, whereas 15 species were larval stages parasitizing piscivorous elasmobranch and teleostean fishes, birds and marine mammals as adults. A new didymozoid trematode, Allonematohnlhrium yucatanense sp. n., is described from the fins of this host. Most findings represent new host- and geographical records. Philometra margolisi, a nematode parasitizing the gonads, is undoubtedly the most important parasite affecting the reproduction of the host, endangering E. morio in aquaculture. Larval anisakid nematodes (Anisakis, Pseudoterranova, Hysterothylacium) recorded from the red grouper in the region of the southern Gulf of Mexico are important from the viewpoint of public health.
Examinations of 29 specimens of the catfish Liobagrus reini Hilgendorf (Siluriformes: Amblycipitidae), a species endemic to Japan, collected from the Sho River, Toyama Prefecture, in central Honshu, revealed the presence of four species of helminth parasites: Plagioporus honshuensis sp. n. (Trematoda), Rhabdochona coronacauda Belouss, 1965, H. japonica Moravec, 1975 and Mexiconema liobagri sp. n. (all Nematoda). The new opccoelid trematode P. honshuensis is characterized mainly by the extent of vitelline follicles, the size ratio of the suckers (1 : 1.7-2.1), the situation of testes near the middle of the body and by the structure, size and shape of the cirrus sac. Allopodocotyle Pritchard, 1966 is considered a junior synonym of Plagioporus Stafford, 1904. The males of R. japonica are described for the first time and conspeciftc females are redescribed; this species is a specific parasite of L. reini. The principle hosts of R. coronacauda are cyprinids and, therefore, its finding in the catfish may indicate an accidental infection; L. reini represents a new host record. M. liobagri (only females were found) from the host’s abdominal cavily is the second known species of this dracunculoid genus, being characterized by the position of the excretory pore and the number (1) of caudal processes in the female. The recorded helminths are briefly described and illustrated and problems of their systematic status are discussed.
A new species of trichosomoidid nematode, Huffmanela paronai sp. n., is established on the basis of its egg morphology and biological characters. The dark-shcllcd, cmbryonatcd eggs of this histozoic parasite occur in masses in the epidermis of the swordfish Xiphias gladius L. (Xiphiidae, Perciformes) from the Ligurian Sea in northern Italy. The eggs are concentrated in groups appearing as black spots in the skin of the fish host, being distributed mainly on the lower part of its body (lower jaw, gill covers, pectoral, anal and caudal fins, lower half of body). The parasite’s eggs are characterised mainly by their shape and markedly small size (48-51 x 21-24 pm), an aspinose surface, relatively small polar plugs, and thick egg wall (3 pm). This is the first Huffmanela species reported from fish in Europe.