Heliocotyle ewingi sp. n. (Monogenea: Monocotylidae) is described from the gills of Myliobatis australis Macleay, 1881 (Myliobatididae) collected from Norfolk Bay near Hobart, Tasmania, Australia. Heliocotyle ewingi can be distinguished readily from the only other species in the genus, Heliocotyle kartasi Neifar, Euzet et Ben Hassine, 1999, by the presence of a single pseudoseptum on each of the peripheral loculi except the posteriormost, eyespots and by the morphology of the male copulatory organ which is a short, straight sclerotised tube which lacks a sclerotised accessory piece. The generic diagnosis is revised to accommodate the new species and the anterior glands are discussed.
Nine Pteromylaeus bovinus (F., Geoffroy St. Hilaire) (Euselachii: Myliobatinae) from the Tunisian coast were examined l'or ectoparasites during 1995, 1996 and 1997. A monogenean found on the gills of seven host specimens is described as a new species and a new genus, Heliocotyle, is proposed to accomodate it. The presence of a single sclerotized haptoral structure on the dorsal surface of the haptor leads us to place this species in the Heterocotylinae Chisholm, Wheeler ct Beverley-Burton, 1995. The genus Heliocotyle is characterized by a haptor with only one dorsal structure and seven loculi, six being subdivided by pseudosepta. Heliocotyle kartasi sp. n. is the type and the only species in this genus.
Just nineteen species of ectoparasitic helminths were found in a survey of over 1,500 individuals of 26 species of sillaginid fishes in the Indo-west Pacific, A twentieth worm is known only from the literature; a twenty-first, also known only from the literature, is considered a doubtful record. Fifteen of the twenty worms are branchial monogeneans, one is a monoge-nean of the pharyngeal plates, one is an ectoparasitic digenean living under the scales, and three are leeches of the mouth cavity and fins. The most common monogeneans were diplectanids (Diplectanum spp. and Monoplectanum spp.) and microcotylids (Polylabris spp.), each with five recently described or redescribed species. Of the remaining monogeneans, three were extremely rare, and two were uncommon. Pseudnbivagina sp. and Polynemicola sp. (Microcotylidae) and Pseudempleurosoma sp. (Ancyrocephalidae) were represented by only a single worm each from three different hosts (Sillago robusta, S. sihama, and S. ingenuua, respectively). The gyrodactylid Gyrodactylus sp, is widespread and was recorded from four species of sillaginids (S. ciliata, S. japonica, S. schomburgkii and S. sihama). Encolyllabe chirrmemi Robinson (Capsalidae) is recorded for the first time from sillaginids, but only on S. aeolus.'Tv/o additional monogeneans are known from sillaginids only in the literature: Dacty-logyrus sp, (Dactylogyridae) is known only from cultured S. sihama', the single specimen of Microcotyle sp. (Microcotylidae) recorded from Sillaginodes punctata is probably a contaminant, since the haptor was missing. The generalist trematode Trans-versolrema Ucinum Manter (Transversotrematidae) was found for the first time in samples of four species of sillaginids (Sillago analis, S. ingenuua, S. lutea and 5. sihama). Three species of piscicolid leeches were encountered: Austrohdella translucens Badham was common on the fins of three large inshore sillaginids (S. ciliata, S. schomburgkii and S. analis); a single specimen of the generalist species Zeylanicobdella arugamensis De Silva was recovered from S. soringa·, and specimens of Z. stellata (Moore) infected S. schomburgkii and S. analis. The diversity of host-specific worms in Sillaginidae is low compared with those of some other Indo-west Pacific fishes.
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.
Differences in the occurrence of monogeneans on lamellae of fish gill arches were observed in this study. These differences were attributed to variations in water current on the gill surfaces or to greater area of certain arches. Two computer simulation programs based on gill area and water current were written to generate parasite melapopulations with clumped patterns. The results obtained were compared with true distributions of selected freshwater monogenean taxa. The combination of both theoretical models (gill area and water current) had greater explanatory power than either of the models alone.