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Haliotrema Pteroisi: Paperna, 1972 (Monogenoidea: Dactylogyridae) was found parasitizing the gill lamellae of devil firefish, Pterois miles (Bennet) (Perciformes: Scorpaenidae), in the Red Sea off Safaga (26°44'N, 33°56'E), Egypt. The parasite species was described based on morphological features of available specimens and transferred to PlatycephalotremaKritsky and Nitta, 2019 (Dactylogyridae) as Platycephalotrema pteroisi (Paperna, 1972) n. comb. The occurrence of Pl. pteroisi off Safaga, Egypt, represented a range extension for the helminth of about 160 km to the southwest of the southern end of the Gulf of Aqaba. The transfer of the species to Platycephalotrema based on an evaluation of morphological features was supported by an analysis of molecular sequences of the 28S rDNA gene of Pl. pteroisi and 49 other dactylogyrid species. Maximum-likelihood, Bayesian inference, and maximum parsimony analyses of this dactylogyrid sequence data revealed H. pteroisi to nest with significant support within the clade of Platycephalotrema spp. During the literature review of dactylogyrid species infecting scorpionfishes, it was determined that Ancyrocephalus sp. of Dyer et al. from luna lion fish Pterois lunulata Temminck and Schlegel collected off Okinawa-jima, Japan represented an undescribed species of Platycephalotrema., (© American Society of Parasitologists 2024.)

The genus Ancyrocephalus sensu lato is a large assemblage of species of dactylogyrid monopisthocotyleans without clear taxonomic boundaries. Despite an urgent need for revision, only three representatives of this taxon have been molecularly characterised so far. We found specimens of Ancyrocephalus curtus , a previously non-genotyped species, in gills of Perccottus glenii caught in the River Syumnyur, Amur Basin, Russia. The aim of this study was to assess the phylogenetic position of this parasite using partial sequences of 28S rRNA gene. In the phylogenetic tree, A. curtus appeared as a sister taxon to the dactylogyrine genus Gobioecetes. The new molecular evidence supports the hypothesis about the non-monophyletic status of Ancyrocephalus sensu lato.

Purpose: Bluegill sunfish (Lepomis macrochirus) are a North American sport fish that exhibit two different male morphotypes. Alpha-males are large, colorful, territorial, and have significant parental investment, while β-males are small, drab, and have two reproductive phenotypes, neither of which involves parental investment. Due to the two different reproductive strategies, the level of interaction between congenerics varies, which may impact parasites that are spread via close contact, such as Monogenoidea that infect the gills. Monogeneans are ectoparasites on the gills and skin of fish hosts that may cause significant pathology in high numbers and be an indicator of host behavior and interaction between hosts., Methods: In this study, 328 L. macrochirus (106 α-males, 92 β-males, and 130 females) were necropsied from 8 lakes and ponds in northwestern Virginia to identify and enumerate monogenean parasites from the gills., Results: Alpha-males had a significantly greater parasite abundance and species richness compared to β-males. This may be due to the increased size and surface area of gills in α-males, increased interaction with females during mating, and stationary behavior when guarding nests, which enhanced the chances of α-males contracting the parasites. This also led to significant differences in the monogenean communities infecting the two morphotypes, which were also significantly influenced by the size of the hosts., Conclusions: It is important in future studies regarding parasitism that behavioral morphotypes within a sex, such as α-male and β-male L. macrochirus in this study, be treated separately as behavioral and morphometric differences between them can potentially lead to differences in parasitism., (© 2023. The Author(s) under exclusive licence to Witold Stefański Institute of Parasitology, Polish Academy of Sciences.)

Examination of the gill lamellae of the Panama grunt Rhencus panamensis (Steindachner) (Haemulidae), golden snapper Lutjanus inermis (Peters), and yellow snapper Lutjanus argentiventris (Peters) (Lutjanidae) (Perciformes) from the coast of the Guerrero State (eastern Tropical Pacific) of Mexico revealed 5 species of Monogenoidea: Euryhaliotrema disparum n. sp. on R. panamensis; Haliotrematoides uagroi n. sp. on L. inermis; and E. anecorhizion Kritsky & Mendoza-Franco, 2012, E. fastigatum (Zhukov, 1976) Kritsky & Boeger, 2002, and E. paracanthi (Zhukov, 1976) Kritsky & Boeger, 2002 on L. argentiventris. Specimens found on R. panamensis were assigned within Euryhaliotrema as a new species possessing the atypical morphology of the male copulatory organ (i.e., a coiled tube with clockwise rings). Haliotrematoides uagroi n. sp. differs from Haliotrematoides striatohamus (Zhukov, 1981) Mendoza-Franco, Reyes-Lizama & Gonzalez-Solis, 2009 from Haemulon spp. (Haemulidae) from the Caribbean Sea (Mexico) in having inner blades on the distal shafts of the ventral and dorsal anchors. The present paper represents the first finding of a species of Euryhaliotrema (E. disparum n. sp.) on a species of Rhencus and the second species on a haemulid host, and H. uagroi n. sp. as the first monogenoidean species described on L. inermis. Euryhaliotrema anecorhizion, E. fastigatum, and E. paracanthi on L. argentiventris in the Pacific coast of Mexico represent new geographical records., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

Interest and use of the lumpfish Cyclopterus lumpus L., 1758, as a cleaner fish in salmon aquaculture has grown significantly over the past 10 years. This has resulted in an explosion of new hatcheries to supply juveniles to the salmon industry. Until recently, these hatcheries have utilized a significant amount of wild broodstock to source the eggs required. Importation of wild fish into aquaculture systems brings an inherent risk of introducing pathogens into the culture systems. Gyrodactylus cyclopteri Scyborskaja, 1948, was found on local wild collected lumpfish that were brought in to start a captive lumpfish aquaculture program in Maine. Little information on the identification or description of G. cyclopteri was available. A re-description of the parasite, supplemented with molecular data, was undertaken to facilitate future identification and support research on this parasite of an emerging, economically significant new aquaculture species.

During a parasitological survey of perciform fishes from Lizard Island, Great Barrier Reef, Australia, we found the following gill monogenoidean species (Platyhelminthes): Euryhaliotrema lizardi n. sp. on Caesio caerulaurea Lacepède, 1801 (Caesionidae) (type host) and Haliotrema weberii n. sp. on Chromis weberi Fowler and Bean, 1928 (Pomacentridae) (type host), Chromis amboinensis (Bleeker, 1871), Chromis atripectoralis Welander and Schultz, 1951 and Caesio teres Seale, 1906. Euryhaliotrema lizardi n. sp. is characterized by having anchors with an elongated straight shaft and point as well as a vaginal canal with two loops before connecting to the seminal receptacle. Ha. weberii n. sp. is distinguished from other congeners by possessing a tubular male copulatory organ (MCO), partially straight. Two previously described dactylogyrids were also found: Haliotrematoides caesionis (Yamaguti, 1953) Kritsky, Yang and Sun 2009) on Caesio cuning (Bloch, 1791) and Ca. teres (new host record) and Haliotrematoides patellacirrus (Bychowsky and Nagibina, 1971) Kritsky, Yang and Sun 2009, on Ca. cuning (new host record). Finally, we provide the first report of a gastrocotylinean pre-adult on Ca. teres. We provide descriptions and illustrations of the new species and the gastrocotylinean pre-adult and include supplemental observations of Ht. caesionis and Ht. patellacirrus. The present findings expand the known spectrum of host species of Euryhaliotrema, Haliotrema and Haliotrematoides to include new caesionid and pomacentrid fishes.

Pseudorhabdosynochus Yamaguti, 1958 is a species-rich diplectanid genus, mainly restricted to the gills of groupers (Epinephelidae) and especially abundant in warm seas. Species from the Mediterranean are not fully documented. Two new and two previously known species from the gills of Mycteroperca spp. (M. costae, M. rubra, and M. marginata) in the Mediterranean and Eastern Atlantic Ocean are described here from new material and slides kept in collections. Identifications of newly collected fish were ascertained by barcoding of cytochrome c oxidase subunit I (COI) sequences. Pseudorhabdosynochus beverleyburtonae (Oliver, 1984) Kritsky & Beverley-Burton, 1986 and P. sosia Neifar & Euzet 2007 are redescribed from type-specimens and new specimens collected off Tunisia and Libya from M. marginata and M. costae, respectively. Pseudorhabdosynochus oliveri n. sp., from M. marginata (type-host) off the Mediterranean coast of France (type-locality), is described from specimens found among voucher specimens of P. beverleyburtonae deposited by Guy Oliver in the collection of the Muséum National d'Histoire Naturelle, Paris. Pseudorhabdosynochus oliveri is distinguished by the shape of its sclerotised vagina; it was not found in the other localities investigated. Pseudorhabdosynochus hayet n. sp. is described from M. rubra (type host) off Senegal (type-locality) and Tunisia. Pseudorhabdosynochus hayet is morphologically similar to P. sosia (type-host: M. costae) but was distinguished by differences in measurements of the vagina and male copulatory organ, different host, and divergent COI sequences. The four species (P. beverleyburtonae, P. sosia, P. oliveri, and P. hayet) share common characteristics such as squamodiscs with 2 innermost circular rows of rodlets and a similar general structure of the sclerotised vagina; we propose to group them into a 'beverleyburtonae group' within Pseudorhabdosynochus.

Gyrodactylus bubyri Osmanov, 1965, a monogenean parasite of Caucasian dwarf goby Knipowitschia caucasica (Berg) described from Aral Sea and subsequently reported from the same host from Strymon River, Greece, is recorded from Atanasovsko Lake, Bulgarian Black Sea coast (the first record of G. bubyri from the Black Sea basin). The species is redescribed by light and scanning electron microscopy as well as the ITS rDNA sequence is obtained. As comparative materials, specimens of G. bubyri from K. caucasica (Strymon River), G. charon Vanhove and Huyse in Vanhove et al., 2014 from Knipowitschia milleri (Acheron Delta, Greece) and G. micropsi Gläser, 1974 from Potamoschistus microps from North Sea (Belgium) are studied. Comparative morphology and molecular data demonstrate that G. micropsi is a junior synonym of G. bubyri (new synonymy). The validity of G. charon is questioned, pending examination of additional materials in order to prove it as a distinct species or as a junior synonym of G. bubyri.

Acanthocercodes n. g. (Diplectanidae) is proposed for Acanthocercodes bullardi n. sp. and three previously described species of Diplectanum all parasites of the gill lamellae of threadfins (Perciformes: Polynemidae). The new genus is characterised by species having peduncular spines composed of an anteriorly directed point and a flattened base from which an anterior root arises. Members of the genus lack auxiliary spinous or sucker-like structures in the haptor. Acanthocercodes bullardi n. sp. is described from the Atlantic threadfin, Polydactylus octonemus (Girard), in the Gulf of Mexico off Louisiana, USA. Diplectanum polynemus Tripathi, 1957 is redescribed and transferred to Acanthocercodes as A. polynemus (Tripathi, 1957) n. comb. based on specimens collected from the fourfinger threadfin, Eleutheronema tetradactylum (Shaw), from the mouth of the River Adelaide, Northern Territory, Australia. Diplectanum spinosum (Maillard & Vala, 1980) (=Pseudodiplectanum spinosum Maillard & Vala, 1980) and Diplectanum megacirrus (Maillard & Vala, 1980) (=Pseudodiplectanum megacirrus Maillard & Vala, 1980) from the lesser African threadfin, Galeoides decadactylus (Bloch), are transferred to Acanthocercodes as A. spinosum (Maillard & Vala, 1980) n. comb. and A. megacirrus (Maillard & Vala, 1980) n. comb., respectively.

Finfish mariculture is typically threatened by parasite and disease outbreaks. Therefore, it is important to identify parasite species of potential risk for this activity. Snappers are valuable food fish worldwide. In the Eastern Pacific, spotted rose snapper (Lutjanus guttatus [Steindachner, 1869]) is a firm candidate for sea-cage aquaculture. In the current study, the parasitism of caged L. guttatus by dactylogyrids was evaluated for the first time during a complete farming period. Twenty five thousand juvenile fish produced at the Research Center for Food and Development (CIAD, Mazatlan Unit) were reared in a sentinel sea-cage from February to November 2012 in Mazatlan Bay, Mexico. A fish sample (n=15) was obtained every month. Dactylogyrids from the left second gill arch were identified and quantified. A total of 18,704 dactylogyrids distributed in three species, Euryhaliotrema perezponcei García-Vargas, Fajer-Ávila and Lamothe-Argumedo, 2008, E. mehen (Soler-Jiménez, García-Gasca and Fajer-Ávila, 2012), and Haliotrematoides guttati García-Vargas, Fajer-Ávila and Lamothe-Argumedo, 2008 (Monogenea: Dactylogyridae) was found, which were able to infect caged L. guttatus since the first month of the farming period. Prevalence of these parasite species was 100% all the time, except for initial low values for E. mehen and H. guttati. The mean intensity of infection of each dactylogyrid species varied significantly between sampling months. Euryhaliotrema perezponcei was the most abundant parasite, reaching the highest mean intensity in May, June and July (154.3, 296.9 and 176.6 parasites/host, respectively). No clear seasonality of infection was observed; however, the influence of the water temperature on the observed infection levels is discussed. There was no mortality, change on behavior or pathological signs. However, given the rapid infection and proliferation of dactylogyrids, particularly E. perezponcei on L. guttaus reared in a sentinel sea-cage, outbreak of these parasites could be expected when this fish species is cultured on a large scale., (Copyright © 2015 Elsevier B.V. All rights reserved.)

A new genus of the Monogenea, Teraplectanum n. g., is proposed for two new species of diplectanids found on the gills of Terapon theraps Cuvier collected off Carey Island, Peninsular Malaysia. The genus is based on a unique arrangement of the male reproductive system. In the new species spermatozoa stored in the seminal vesicle and secretions stored in the prostatic reservoir are transferred into, and mixed to form semen within, a special sclerotized auxiliary piece (SAP), and not within the copulatory tube as occurs in the majority of monogeneans. Teraplectanum species also possess a unique sclerotized vaginal loop through which the vaginal tube passes en route from the vaginal pore to the seminal receptacle. The two new species are Teraplectanum crassitubus n. sp. (type species) and T. angustitubus n. sp. They differ from each other mainly in the morphology of their copulatory tube: in T. crassitubus, the proximal region of this tube is thicker compared to the slender proximal region in T. angustitubus, although in both cases the tube tapers and twists distally. Of the known diplectanid species, only Diplectanum undulicirrosum Zhang et al., 2000 (currently considered incertae sedis) possesses such sclerotized hard parts, which suggests the same type of arrangement of the male reproductive system. Consequently, D. undulicirrosum is re-assigned to this new genus as Teraplectanum undulicirrosum (Zhang et al., 2000) n. comb. The copulatory tube of T. undulicirrosum is similar to the slender, undulating copulatory tube of T. angustitubus but does not taper distally as in the latter species.

Fish monogeneans are lethal parasites in aquaculture. We provide the first experimental evidence that a notorious fish monogenean, Neobenedenia sp., can produce viable eggs in isolation for three consecutive generations. We infected individual, isolated, farmed barramundi, Lates calcarifer (Bloch) with a single oncomiracidium (larva) of the hermaphroditic monogenean Neobenedenia sp.. Isolated parasites reached sexual maturity at day 10 post-hatch (24°C, 35‰) and laid ∼3,300 embryonated eggs over 17 days [corrected]. Egg production rapidly increased following sexually maturity on day 10 (58±15 eggs) and peaked on day 15 (496±68 eggs) before gradually decreasing. Neobenedenia sp. exhibited egg laying and egg hatching rhythms. Parasites laid eggs continuously, but egg production increased in periods of darkness (64.3%), while the majority of oncomiracidia (81%) emerged from eggs in the first three hours of light. Eggs laid by isolated 'parent' parasites hatched and individual emerging oncomiracidia were used to infect more individual, isolated fish, with three consecutive, isolated, parasite generations (F1, F2 and F3) raised in the laboratory. Infection success and egg hatching success did not differ between generations. Our data show that one parasite, in the absence of a mate, presents a severe threat to captive fish populations.

Recent studies indicate that the northwestern Pacific Ocean is an ideal system in which to study and understand the roles of the Pleistocene sea-level fluctuations and ocean currents in shaping phylogeographic patterns of species, but most of these investigations have been concerned with vertebrates, and only a few have focused on invertebrates. In the present study, we examined the genetic population structure and historic demography of a platyhelminth species, Gotocotyla sawara (Monogenea, Gotocotylidae), a gill parasite of Japanese Spanish mackerel, Scomberomorus niphonius , along the coast of China. A fragment of the mitochondrial cytochrome oxidase I (COI) gene for 169 individuals and the internal transcribed spacers for 24 individuals were sequenced from specimens representing 8 populations of this parasite along the coast of China. High levels of COI haplotype diversity (0.9994) and nucleotide diversity (0.015805) were detected for G. sawara. Phylogenetic analysis revealed no phylogeographical pattern for G. sawara in the sample area. Analysis of molecular variance (AMOVA) revealed no significant differences at all hierarchical levels, and pairwise FST analysis demonstrated a high rate of gene flow of this parasite among different populations in coastal Chinese waters. Moreover, the exact test of differentiation supported the null hypothesis that G. sawara along the coast of China constitutes a panmictic population. Both neutrality tests and mismatch distribution revealed that G. sawara underwent population expansion in the late Pleistocene era. Recent range expansion after the last glacial maximum and insufficient time to attain migration-drift equilibrium may account in part for the lack of genetic structure in the geographic areas considered in this study. Dispersal of parasite eggs and larvae along ocean currents, coupled with the long-distance migrations of host fishes, could also be responsible for genetic homogeneity of this parasite. It is also possible that other hosts of this monogean, such as the ridged-eye flounder, Pleruonichthys cornutus, may contribute to the genetic mixing of Gotocotyla sawara populations.

Background: The Sultanate of Oman's aquaculture industry is expanding with an on-going assessment of potential new fish species for culture. The king soldier bream, Argyrops spinifer (Forsskål) (Sparidae), is one such species that is under consideration. During a routine health assessment of specimens caught in the Sea of Oman throughout the period November 2009 to March 2011, a number of gill polyopisthocotylean monogeneans were recovered., Methods: A subsequent study of the monogeneans using a range of morphology-based approaches indicated that these were Bivagina heterospina Mamaev et Parukhin, 1974. In the absence of pre-existing molecular data, an expanded description of this species is provided, including a differential diagnosis with other species and genera belonging to the subfamily Microcotylinae Monticelli, 1892 with the subsequent movement of this species to a new genus to accommodate it., Results: The polyopisthocotyleans collected from the gills of A. spinifer appear to be unique within the family Microcotylidae Taschenberg, 1879 in that, morphologically, they possess a pair of large, muscular vaginae each armed with a full crown of 16-18 robust spines and a unique dorsal region of folded tegument, which permits their discrimination from species of Bivagina Yamaguti, 1963. Sequencing of the SSU rDNA (complete 1968 bp) and LSU rDNA (partial 949 bp) places the specimens collected during this study within the subfamily Microcotylinae, but the LSU rDNA sequence differs from Bivagina and also from other microcotylid genera. Morphological features of B. heterospina sensu Mamaev et Parukhin, 1974 and the specimens collected from the current study are consistent with one another and represent a single species. The vaginal armature of these worms is unique and differs from all other genera within the Microcotylinae, including Bivagina, and its movement to Omanicotyle n. gen. to accommodate this species is proposed., Conclusions: A new genus, Omanicotyle n. gen., is erected to accommodate Omanicotyle [Bivagina] heterospina n. comb. which represents the first monogenean to be described from Omani marine waters. Given the pathogenic potential of microcotylids on captive held fish stocks, a full assessment of Omanicotyle heterospina n. gen. et n. comb. is now required before large-scale production commences.

Euryhaliotrematoides mehen n. sp. (Monogenea: Dactylogyridae) is described based on specimens collected from the gills of the spotted rose snapper Lutjanus guttatus (Steindachner) off Mazatlan, Sinaloa, on the northwestern coast of Mexico. The synapomorphy of this genus is the presence of a funnel-shaped base of the male copulatory organ. This new species differs from all other species of the genus by possessing a male copulatory organ with a base with a thickened margin and a membranous accessory piece resembling a scarf and covering about 60% of its distal region. PCR products of the 28S rRNA (831 bp) and 18S rRNA (662 bp) genes were sequenced and submitted to GenBank (accession numbers HQ615997 and JF938069, respectively). BLASTn searches revealed no 100% identical hits with the previously registered monogenean sequences.

Protogyrodactylus ethiopicus sp. n. and P. kritskyi sp. n. are described from the gills of Gerres nigri Günther (Gerreidae, Perciformes) captured from the estuary of the Sine-Saloum River (Senegal, West Africa). These new species differ from previously described species within the genus by a mid- or dextro-ventral vaginal opening (dextral in all other species). They are part of a morphological species group within Protogyrodactylus Johnston et Tiegs, 1922 that has the tip of the superficial root of the ventral anchor resembling a hook and two anterior projections on the anterior margin of the ventral bar. Protogyrodactylus ethiopicus differs from the remaining species in this group mainly by the morphology of the base of the male copulatory organ (MCO), which is disk-shaped, and the shape of the anterior projections of the ventral bar (round in the new species and relatively elongate in the other species of the group). The other new species, P. kritskyi, differs from all others in the same morphological group in having a MCO with a greatly expanded base that bears a heel-like subterminal sclerotization.

The spatial distribution and coexistence of monogenean dactylogyrids was assessed on the gills of 63 specimens of wild spotted rose snapper, Lutjanus guttatus (Steindachner), caught in the Mazatlan Bay, Sinaloa, Mexico. Five species are reported: Euryhaliotrema perezponcei Garcia-Vargas, Fajer-Avila et Lamothe-Argumedo, 2008, Euryhaliotrematoides sp., Haliotrematoides spinatus Kritsky et Mendoza-Franco, 2009, H. plectridium Kritsky et Mendoza-Franco, 2009, and H. guttati Garcia-Vargas, Fajer-Avila et Lamothe-Argumedo, 2008. All except E. perezponcei and H. guttati represent new geographical records for the Pacific coast. The most prevalent dactylogyrid species was E. perezponcei (100%), H. plectridium and H. spinatus had > 80% prevalence, and H. guttati and Euryhaliotrematoides sp. had the lowest prevalence. The mean abundance of H. plectridium and E. perezponcei was close to 60 parasites/fish, whereas Euryhaliotrematoides sp. and H. guttati had the lowest abundance. The dactylogyrid species exhibited a tendency for attachment to gill arch 2: 25% attachment occurring on gill arch 1, 30% on 2, 27% on 3 and 18% on 4, and showed a significant preference for the central sector of the gill (42%). Haliotrematoides plectridium had a preference for attachment to gill arches 2 and 3 and the central sector. Haliotrematoides spinatus tended to settle on the gill arches 2 and 3 and had a preference for the central sector. Euryhaliotrema perezponcei tended to settle on the gill arches 1 and 2 and the anterior gill sector. Euryhaliotrematoides sp. and H. guttati did not show a preference for any gill arch or sector. The intraspecific aggregation was stronger than the interspecific aggregation, indicating that all the dactylogyrid species on spotted rose snapper were aggregated, and there was no evidence of competition among the species.

A survey of pumpkinseed Lepomis gibbosus from a stillwater fishery in southern England revealed infections by the ancyrocephalid monogenean Onchocleidus dispar at 100% prevalence. Host specificity of O. dispar to North American centrarchid fish suggests that it is a non-native parasite, introduced to Britain with L. gibbosus. Mean intensity of O. dispar was significantly higher in male (25.5 parasites) compared to female (15) and immature (7) hosts, but was not influenced by host standard length or sampling time. This sex-biased parasitism is likely to be related to both ecological and physiological factors, such as differential exposure to infective stages during nest building, or higher susceptibility to infection due to enhanced host stress levels. O. dispar significantly dominated the external surfaces and the outer gill arches. Analysis of the spatial distribution of the parasite between the 9 regions of gill surface determined that as density increased, higher numbers of parasites were found on the anterior and central gill regions compared to posterior (distal) regions. Apparent microhabitat selection is discussed in terms O. dispar life cycle, maximising oxygen availability, avoiding unstable areas and increasing intraspecific contact. The absence of O. dispar in the gills of roach, rudd and gudgeon sampled from the same fishery supports the assumption that this parasite is currently of little threat to native fish populations.

During surveys of helminth parasites of marine fishes from the Pacific coast of the Guerrero State in Mexico, 2 undescribed species of Haliotrema Johnston and Tiegs, 1922 (sensu Young, 1968) (Dactylogyridae) were found infecting the gills of the giant hawkfish Cirrhitus rivulatus Valenciennes, 1846 (Perciformes, Cirrhitidae), i.e., Haliotrema cirrhitusi n. sp. and Haliotrema pollexinus n. sp. The new species are similar with respect to the morphology of the anchors with base-shaft junction crazed, hinged, or both; dorsal anchors with an elongate superficial root; a tubular male copulatory organ (MCO) with a cylinder-shaped base diagonally opening; and a membranous accessory piece, shaped like a vane, encircling MCO to form 2 complete spirals from the anterior margin of base to the terminal portion of the MCO. While H. cirrhitusi and H. pollexinus differ from all other species of the genus in the general morphology of the copulatory complex, only H. pollexinus notably differs from all these species in having a superficial, blade-like projection from the inner surface on the distal shaft of anchors. Haliotrema cirrhitusi and H. pollexinus are the only members of the genus recorded in the Mexican Pacific and from a cirrhitid host.

Gotocotyla acanthura (Parona & Perugia, 1896) Meserve, 1938 collected from the gills of Pomatomus saltatrix from the coast of the state of Rio de Janeiro state was analyzed using scanning electron microscopy (SEM). The study demonstrated the presence of a buccal cavity, a genital atrium on the ventral surface and a muscular structure on the dorsal surface at the level of the body constriction. An elongated haptor with 80 to 120 pedunculated clamps symmetrically distributed in two rows, with rib-like thickenings and a curved lappet bearing a pair of hooks at the posterior extremity of the body were also observed. The cirrus could be seen protruding from the genital atrium, armed with pectinate spines along its length and presenting up to eight pointed spines around the genital atrium.

Four species of Haliotrema Johnston & Tiegs, 1922, including three new taxa, are described from the gills of two species of coral reef fishes, Zanclus cornutus (Linnaeus) and Acanthurus nigrofuscus (Forsskål), off the Dongsha Islands in the South China Sea. Haliotrema dongshaense n. sp., from Z. cornutus, is differentiated from other existing congeneric species by its peculiar male copulatory organ, comprising a harp-shaped copulatory tube and a cup-shaped base, and two groups of short longitudinal muscles lying on either side of the vaginal vestibule. Haliotrema zigmoidocirrus n. sp. from Z. cornutus and H. nigrofusci n. sp. from A. nigrofuscus are differentiated from other congeneric species by their male copulatory organ, which has a cup-shaped base, bell-shaped middle and Z-shaped distal part, and the latter can be readily differentiated from the former by its distinctively wider haptor and longer connecting bars. Haliotrema sicklocirrus Wang, 2007, from Z. cornutus, is redescribed with additional details, including the sinistral position of the accessory piece of the male copulatory organ, the absence of eyespots and the morphology of the connecting bars.

During a parasitological survey of two non-native fish species-racer goby Neogobius gymnotrachelus and monkey goby Neogobius fluviatilis-in the Włocławek Reservoir on the lower Vistula River, the monogenean Gyrodactylus proterorhini was recorded for the first time in Poland, and for the first time, the racer goby was listed as the parasite host. Specimens of G. proterorhini were detected on body surface, fins, and gills of the fish studied. In 2006, the monkey goby was infected with the prevalence 41%, racer goby with the prevalence of 47%, at maximal intensity of 6 and 9 parasites per fish, (respectively). The infection level in relation to the fish size and sampling season was also discussed. The presented study supports the hypothesis of progressive introduction of the parasite with gobiids to the colonized areas.

Lamellodiscus dentexi Aljoshkina, 1984, a gill parasite of Dentex macrophthalmus (Bloch), is redescribed based on new material from the northwest coast of Africa (Senegal and Morocco). Three new species of Lamellodiscus Johnston et Tiegs, 1922 from D. macrophthalmus are described, Lamellodiscus toguebayei sp. n., L. vicinus sp. n., and L. triacies sp. n., all belonging to the "ignoratus" group. They can be distinguished from all other species of this group by the size and shape of male copulatory organ and sclerotised parts of the haptor. Considering the peculiar morphology of the male copulatory organ (long and thin tube) we propose to put together L. dentexi, L. virgula Euzet et Oliver, 1967 and L. obeliae Oliver, 1973 to form the "elongatus" type within the "elegans" group.

Relationships between the three classes of Neodermata (parasitic Platyhelminthes) are much debated and restrict our understanding of the evolution of parasitism and contingent adaptations. The historic view of a sister relationship between Cestoda and Monogenea (Cercomeromorphae; larvae bearing posterior hooks) has been dismissed and the weight of evidence against monogenean monophyly has mounted. We present the nucleotide sequence of the complete mitochondrial (mt) genome of Benedenia seriolae (Monogenea: Monopisthocotylea: Capsalidae), the first complete non-gyrodactylid monopisthocotylean mt genome to be reported. We also include nucleotide sequence data for some mt protein coding genes for a second capsalid, Neobenedenia sp. Analyses of the new mt genomes with all available platyhelminth mt genomes provide new phylogenetic hypotheses, which strongly influence perspectives on the evolution of diet in the Neodermata. Our analyses do not support monogenean monophyly but confirm that the Digenea and Cestoda are each monophyletic and sister groups. Epithelial feeding monopisthocotyleans on fish hosts are basal in the Neodermata and represent the first shift to parasitism from free-living ancestors. The next evolutionary step in parasitism was a dietary change from epithelium to blood. The common ancestor of Digenea+Cestoda was monogenean-like and most likely sanguinivorous. From this ancestral condition, adult digeneans and cestodes independently evolved dietary specialisations to suit their diverse microhabitats in their final vertebrate hosts. These improved perspectives on relationships fundamentally enhance our understanding of the evolution of parasitism in the Neodermata and in particular, the evolution of diet., (Copyright (c) 2010. Published by Elsevier Ltd.)

Microcotyle arripis Sandars, 1945 is redescribed from Arripis georgianus from four localities: Spencer Gulf, Gulf St. Vincent, off Kangaroo Island and Coffin Bay, South Australia, Australia. Kahawaia truttae (Dillon & Hargis, 1965) Lebedev, 1969 is reported from A. trutta off Bermagui, New South Wales and is redescribed from a new host, A. truttaceus, from four localities in South Australian waters: Spencer Gulf, Gulf St. Vincent, off Kangaroo Island and Coffin Bay. Phylogenetic analysis of the partial 28S ribosomal RNA gene (28S rRNA) nucleotide sequences for both microcotylid species and comparison with other available sequence data for microcotylid species across four genera contributes to our understanding of relationships in this monogenean family.

The sclerotized attachment organ of monogeneans has been widely used to address fundamental questions in ecology and evolution. However, traditional morphometric techniques appear to be partially inadequate and non-optimal. Traditional linear measurements mainly provide information on the size of sclerites but provide very little information, if any, on their shape. The shape of sclerites is indeed virtually unexplored and its implication for ecological and evolutionary processes remains to be analyzed. This study aims to both introduce and illustrate the use of geometric morphometrics in order to study sclerites of monogeneans in a biogeographic context. To do this, we investigated morphological variation patterns among four populations from the Pacific Ocean and six monogenean species through traditional and geometric morphometric techniques. Unlike the traditional method, the geometric morphometric method yielded a high percentage of individuals correctly classified to the four populations, providing strong evidence for phenotypic variability, divergence and local adaptation among islands without evolutionary constraint. Moreover, the traditional method also resulted in inconsistent interpretations of shape variations. This study highlighted the limitations that may arise when using traditional morphometric techniques and emphasizes that considerable information about the shape of sclerotized haptoral parts is added by using geometric morphometrics. Given the prominent taxonomic, ecological and evolutionary role of the haptor for characterizing monogeneans, we ultimately discuss the potential broad use of geometric morphometrics in a wide variety of ecological and evolutionary contexts. This powerful approach might allow a more robust estimation of the extent to which traditional evolutionary theories based on size of sclerites are congruent with their shape.

Three new species of Lamellodiscus are described from four (including two undescribed) species of Gymnocranius off New Caledonia, South Pacific. All three species have a similar body anatomy and morphology of the haptoral hard parts and are distinguished on the basis of the male copulatory organ (MCO). Lamellodiscus tubulicornis n. sp. (type-host: G. grandoculis; other host: Gymnocranius sp. B) has an MCO with a tube and horn; L. magnicornis n. sp. (type-host: G. grandoculis; other hosts: G. euanus, Gymnocranius sp. A and Gymnocranius sp. B) has an MCO with a long horn and a membrane; L. parvicornis n. sp. (type-host: G. euanus; other hosts: G. grandoculis and Gymnocranius sp. B) has an MCO with a small horn and a membrane. Lamellodiscus epsilon Yamaguti, 1968 is redescribed based on the type-specimens (from Monotaxis grandoculis off Hawaii). Lamellodiscus sp. is recorded from Gnathodentex aureolineatus off New Caledonia. All these five species have lamellodiscs that exhibit a unique characteristic: the second lamella forms an almost closed circle, in contrast to all other described species of Lamellodiscus in which the second lamella has the form of one or two crescents. Lamellodiscus spp. are usually classified in two groups, the 'ignoratus' and 'elegans' groups, according to the structure of the lamellodisc; we propose a new 'tubulicornis' group for these five species. In addition to their lamellodisc structure, species of the tubulicornis group are also characterised by their egg (elongate in contrast to tetrahedral in the two other groups) and their hosts (monotaxine lethrinids as opposed to mainly sparids). The generic diagnosis of Lamellodiscus given by Amine & Euzet (2005) is amended to include species with elongate eggs.

Three species of Volsellituba n. g. and two species of Pennulituba n. g. are described from the gills of the yellowfin goatfish Mulloidichthys vanicolensis (Valenciennes) off New Caledonia (South Pacific). Volsellituba and Pennulituba resemble dactylogyrid genera whose species lack eye-spots and possess tandem or slightly overlapping gonads, a single prostatic reservoir, a male copulatory organ without an accessory piece, a dextroventral non-sclerotised vagina, ventral and dorsal anchor/bar complexes, and hooks with shanks comprising a single slender unit. Volsellituba n. g. is characterised by its species having ventral tegumental folds at the level of the vaginal duct, a male copulatory organ with a subterminal basal opening and a two-piece dorsal bar. The following new species of Volsellituba are described: V. orchidea n. sp. (type-species), V. nabla n. sp. and V. elephantina n. sp. Pennulituba n. g. is distinguished by its species possessing a male copulatory organ with a wing-shaped membrane and a dorsal bar with a poorly to non-sclerotised medial part. This genus includes P. piratifalx n. sp. (type-species) and P. cymansis n. sp. A tabular summary of the species of Haliotrema Johnston & Tiegs, 1922 reported from mullids is provided.

One previously described species, Haliotrema striatohamus Zhukov, 1981, found off the coast of Cuba and Campeche (Gulf of Mexico), is redescribed and transferred to Haliotrematoides Kritsky, Yang and Sun, 2009, as Haliotrematoides striatohamus ( Zhukov, 1981) n. comb. This transfer is based on the study of new specimens of this species found in the gill lamellae of grunts, i.e., Haemulon aurolineatum Cuvier, Haemulon plumierii (Lacepède), and Haemulon sciurus (Shaw) (Haemulidae), all from the southern coast of Quintana Roo, Mexico. In addition, another previously described species, Haliotrema brevispirocirrus Zhukov, 1981 from Haemulon striatum (Linnaeus) from Havana, Cuba, is also transferred to Haliotrematoides based on the comparative morphology of its original description. Data are provided for prevalence and mean intensity as well as for the morphologic and biometric variability of H. striatohamus from different hosts. The new replacement of H. striatohamus ( Zhukov, 1981) n. comb. and H. brevispirocirrus (Zhukov, 1981) n. comb. infecting these taxa represents the first known species of Haliotrematoides on these fishes and new geographical records for these dactylogyrid monogenoids.

Aetheolabes goeldiensis n. g., n. sp. (Diplectanidae) is described from the gills of 'pescada' Plagioscion sp. (Sciaenidae) collected from the Baía de Marajó, about 30 km north of Belém, Pará, Brazil. The monotypic Aetheolabes n. g. is characterised, in part, by its type-species having the haptor and haptoral sclerites modified as a clasp for attachment to the gill tissue of its host, the copulatory complex situated far posterior to the intestinal bifurcation near the mid-length of the trunk, the vaginal pore apparently within the genital atrium, the tegument lacking scales, anchors atypical for diplectanids, and by lacking peduncular spines and squamodiscs. A. goeldiensis n. sp. closely resembles Diplectanum umbrinum Tripathi, 1957 from India and China by the haptoral sclerites forming a clasp, but differs from it primarily by the orientation of the reproductive organs and absence of squamodiscs.

Species of Lamellodiscus Johnston & Tiegs, 1922 are described from the gills of Lithognathus mormyrus (Linnaeus) in the Mediterranean Sea. A new nomenclature for a male copulatory organ with two articulated pieces is proposed: the hollow piece is referred to as the penis and we propose the term 'vectis' for the entirely sclerotised piece. It is shown that L. verberis Euzet & Oliver, 1967 actually comprised two species, L. verberis (sensu stricto), which is redescribed based on both the type-material and new material from the type-locality off Sète (France) and from off Sfax (Tunisia), and L. flagellatus n. sp. The two species are distinguished by the shape of the male copulatory organ and vagina (penis lacking a thread-like extension and vaginal duct short in L. verberis, versus penis with a thread-like extension and vaginal duct long in L. flagellatus); the vectis is similar in both species. Access to new material of L. mormyri Euzet & Oliver, 1967 from the same host species also enabled a redescription of this species. The status of L. ignoratus Palombi, 1943, another species from Lithognathus mormyrus, is discussed. A possible scenario for the synxenic speciation of these congeneric parasites of L. mormyrus is proposed.

During investigations of fish parasites in the Neotropics (including the state of Veracruz and the Yucatán Peninsula in the Gulf of Mexico, the Chautengo Lagoon on the Pacific coast of the state of Guerrero in Mexico, and Lake Gatun in the Panama Canal), three monogenoidean (Dactylogyridae) species were found parasitizing the gills of gerreids (Gerreidae): Aristocleidus hastatus Mueller, 1936, was recovered from Eugerres plumieri (Cuvier) and Diapterus auratus Ranzani in Veracruz, from D. auratus and Diapterus rhombeus (Cuvier) in Yucatán, from Eugerres brasilianus (Cuvier) in Panama (all new hosts and geographical records), and from D. peruvianus (Cuvier) and Gerres cinereus (Walbaum) in Guerrero; Aristocleidus lamothei Kritsky and Mendoza-Franco, 2008, was recovered from E. plumieri in Veracruz and from D. rhombeus in Yucatan (new hosts and geographical records), and Aristocleidus sp. was recovered from G. cinereus in Guerrero. Results from this study suggest that species of Aristocleidus exhibit wide host specificity within gerreid fishes and that geminate species within this parasite genus may have originated with the formation of the Isthmus of Panama (3.1 to 3.5 ma). Evidence is also presented suggesting the potential role of the Panama Canal as a passageway allowing the interoceanic dispersal of Aristocleidus species across the isthmus.

Haliotrema leporinus n. sp. and Haliotrema pratasensis n. sp. are described from the gills of surgeonfishes (Acanthuridae) off the Pratas Islands in the South China Sea. Haliotrema leporinus n. sp. differs from all other members of the genus by possessing a rabbit-head-shaped sclerotized piece in the haptor. Haliotrema pratasensis n. sp. differs from its congeners by having a copulatory organ with a clockwise coil and a funnel-shaped base and by lacking an accessory piece.

Yellowtail kingfish, Seriola lalandi support significant commercial and recreational fisheries as well as aquaculture operations throughout the world. Metazoan parasite infections of S. lalandi are of considerable economic and ecological importance, yet very little is known about wild parasite assemblages. S. lalandi were collected from the east coast and south coast of Australia and examined for metazoan parasites. Forty-three parasite taxa were identified, including 26 new host records. Four of the parasite species recovered have been previously associated with disease or mortality in Seriola aquaculture. Comparisons are made between ectoparasite and endoparasite prevalence and intensity of S. lalandi from New South Wales and Victoria. S. lalandi sampled from the east coast of Australia shared ectoparasites previously documented from this species in New Zealand, providing support that S. lalandi in the Tasman Sea comprise a single stock. Based on previously used criteria to evaluate the suitability of parasites as biological tags, the monogenean Paramicrocotyloides reticularis Rohde and the copepod Parabrachiella seriolae Yamaguti and Yamasu may be potentially useful for stock discrimination.

Nine species of Siganus (Perciformes: Siganidae) were examined for dactylogyrids (Monogenoidea) from the Red Sea, Egypt; the Great Barrier Reef, Australia; and the South China Sea, China. Species of Tetrancistrum were found on siganids from all 3 localities; Pseudohaliotrema spp. were restricted to siganids from the Great Barrier Reef; and species representing Glyphidohaptor n. gen. were found on siganids from the Red Sea and Great Barrier Reef. Siganus argenteus from the Red Sea and Siganus vulpinus from the Great Barrier Reef were negative for dactylogyrid parasites. Glyphidohaptor n. gen. is proposed for 3 species (2 species new to science) and the new species are described: Glyphidohaptor phractophallus n. sp. from Siganus fuscescens from the Great Barrier Reef; Glyphidohaptor sigani n. sp. from Siganus doliatus (type host), Siganus punctatus, Siganus corallinus, and Siganus lineatus from the Great Barrier Reef; and Glyphidohaptor plectocirra (Paperna, 1972) n. comb. (= Pseudohaliotrema plectocirra Paperna, 1972) from Siganus luridus and Siganus rivulatus from the Red Sea.

In this paper, three separate instances of an association between an ectoparasite, Cyclocotyla bellones (Otto, 1821) (Monogenea: Diclidophoridae) and ectoparasitic isopods have been reported for the first time from the Aegean Sea coasts of Turkey. The isopods were all of the family Cymothoidae: Ceratothoa oestroides, C. parallela, Emetha audouini.

This study was carried out to investigate the reasons for scale loss, hemorrhage and local lesions on the skin of cultured meagre (Argyrosomus regius Asso, 1801), that are an alternative to the sea bass and sea bream. All of the 40 fish examined (5.63 +/- 0.89 kg in weight, 91.3 +/- 3.6 cm in length) had parasites on the area with lesions and the parasite was identified as Benedenia sciaenae van Beneden, 1856 (Monogenea: Capsalidae) after examination. The dimensions of the parasite were measured and drawn. This is the first report of B. sciaenae in Turkey.

Two monogeneans species, Polylabris mamaevi Ogawa & Egusa, 1980 and Tetrancistrum nebulosi Young, 1967, are sympatric on the gills of Siganus fuscescens (Houttugn, 1782) in the South China Sea. An investigation into their distribution on the host's gills based on monthly samples from both wild and caged populations revealed that these 2 species co-occurred on the same gill arches, but they were segregated. P. mamaevi attached to the distal half of the gill filaments, whereas T. nebulosi attached to the proximal half. This difference may partly be attributed to microhabitat specialization. Microhabitat distributions were intensity dependent for both species. As intensity increased, monogeneans were increasingly found on the second, third, and even fourth gill arches, and niche breadths increased. The changes in distribution and niche breadths at the host gill arch level in relation to differences in host size and sampling period were considered to represent a functional response to increased intensity. Differences in host resources, in either net-caged or wild populations, did not significantly influence the parasite distributions at the host gill arch level. Simultaneous infections of these 2 species were common, but there was no evidence of negative interspecific interactions.

Cornutohaptor nigrescensi n. sp. (Diplectanidae) is described from the gills of the black snook, Centropomus nigrescens (Perciformes: Centropomidae) from the Pacific coast of Mexico. Cornutohaptor n. gen. is proposed for this new species and is characterized by possessing 2 intestinal ceca terminating blindly; a germarium looping right intestinal cecum; bilobed testis; 2 seminal vesicles; 7 pairs of hooks, each with protruding thumb; a grooved ventral bar and coiled male copulatory organ (MCO); an accessory piece comprising a "baglike structure" with an appendage; dorsal bars associated parallelly to body midline; and no adhesive accessory organs on the haptor. Cornutohaptor differs from all confamilial genera by including species with anchors with straight and deep root longest, hook pair 1 reduced in size, MCO with counterclockwise rings, and by the morphology of the accessory piece. Cornutohaptor nigrescensi most closely resembles species of Murraytrema Price, 1937, Lobotrema Tripathi, 1937, and Murraytrematoides Yamaguti, 1958, because of the absence of squamodiscs or lamellodiscs on the haptor and tegumental scales on the posterior portion of the body. Cornutohaptor differs from these genera in the position and number of haptoral bars (2 bars in Lobotrema spp., dorsal bars transversally associated in Murraytrema and Murraytrematoides spp.) and in having a coiled MCO (copulatory organ is a comparatively straight, poorly sclerotized tube in Murraytrematoides spp.). This is the first diplectanid described from a centropomid along the Pacific coast of Mexico.

Urbanization has deleterious effects on water quality and biota in stream systems. This project used caged bluegill (Lepomis macrochirus) to assess metazoan fish parasite communities in 2 urbanizing streams of the upper San Antonio River Basin, Bexar County, Texas. Field studies on Leon and Salado creeks were conducted during late summer in 1999 and 2000. Juvenile bluegill, obtained from a local aquaculturist, were held in cages for 10-22 days at middle and lower watershed sites to expose them to in-stream conditions and to allow parasite communities to establish. After removal from cages, fish were examined for metazoan parasites. In 2000, wild Lepomis spp. also were collected at study sites for parasite assessment. In both years, physical and chemical water properties were monitored at each site. Of the 120 fish examined for parasites, 96.7% were infected by at least 1 organism from among the 11 parasitic taxa observed. For caged fish, both diversity and equitability of parasite communities tended to be lower at the more eutrophic downstream sites; accordingly, parasite diversity and equitability were inversely correlated with nitrate concentrations. Ectoparasites were more prevalent in caged fish and endoparasites were more abundant in wild fish. An Ergasilus sp. copepod and a Posthodiplostomum sp. trematode dominated the ecto- and endoparasite faunas, respectively. This study suggests that assessment of watershed health can benefit from comparative cage studies of parasite community development involving sentinel fish species.

Species of Pseudorhabdosynochus were studied from fresh specimens collected from Epinephelus fasciatus and E. merra off New Caledonia, South Pacific, and specimens deposited in Museums. Experiments on two species demonstrated that the sclerotised hollow organs, such as the quadriloculate male copulatory organ and the vagina, may show differences in measurements of up to 50% when flattened. P. caledonicus n. sp. is described from E. fasciatus in New Caledonia, on which it is relatively rare; it is distinguished on the basis of the quadriloculate organ, which has a very thin anterior wall, the sclerotised parts of the vagina in form of a straight tube with a star-shaped lateral structure, and the squamodiscs composed of 11 open rows of rodlets. P. cupatus (Young, 1969) is redescribed from abundant material from E. fasciatus off New Caledonia (new geographical record) and compared with paratype specimens from Australia (from E. fasciatus and E. merra) and specimens from E. fasciatus in the Red Sea (both herein redescribed and figured); a specimen was also found on a slide from E. merra off Vanuatu. P. melanesiensis (Laird, 1958) is redescribed from material from E. merra off New Caledonia (new geographical record) and compared with type-specimens (herein redescribed and figured) from the same host off Vanuatu. The structure of the sclerotised vagina in P. cupatus and P. melanesiensis is very similar, with a thin-walled tube and a heavily sclerotised structure with three loculi. P. vagampullum (Young, 1969) is redescribed from the paratypes from E. merra from Australia, but was not found in New Caledonia; specimens included among its paratypes (from E. merra in Australia), but different, are herein attributed to Pseudorhabdosynochus sp. 3. P. lantauensis (Beverley-Burton & Suriano, 1981) is redescribed from the paratype specimens from E. longispinis off Hong-Kong. A specimen found among the paratypes of P. cupatus belongs to a different species, herein designated as Pseudorhabdosynochus sp. 1. Specimens from E. longispinis off Hong-Kong, previously attributed to P. cupatus, are attributed to another species, Pseudorhabdosynochus sp. 2. The three species P. cupatus, Pseudorhabdosynochus sp. 1 and Pseudorhabdosynochus sp. 2 have in common a 'lamellosquamodisc' composed of central telescopic lamellae and peripheral rows of rodlets; they can be distinguished by the shape of the sclerotised vagina and measurements of the haptoral hard-parts. Specimens from E. longispinis off Hong-Kong, previously attributed to P. vagampullum, probably belong to a different species. Consequently, after these modified determinations, P. cupatus parasitises only E. fasciatus and E. merra, and P. melanesiensis and P. vagampullum parasitise only E. merra. With their wide geographical distribution and different species of Pseudorhabdosynochus in different localities, E. fasciatus and E. merra appear to represent excellent models for investigating monogenean biogeography in the Indo-Pacific Ocean.

Pseudorhabdosynochus hirundineus n. sp. is described from specimens collected from the gills of Variola louti off Nouméa, New Caledonia, South Pacific. No diplectanid was found on V. albimarginata from the same location. The male sclerotised quadriloculate organ of P. hirundineus is 42 microm in internal length, with a long posterior tube; and the sclerotised vagina, 36 microm in length, is composed of a long tube with anterior open trumpet and two posterior, heavily sclerotised chambers. The two squamodiscs, each with 11-15 rows of rodlets and no central closed row of rodlets, are dissimilar in shape, the ventral being round and the dorsal being oval. By the morphology of its sclerotised vagina, P. hirundineus appears close to P. epinepheli (Yamaguti, 1938) but it is differentiated from it by the shape of its squamodiscs. Pseudorhabdosynochus spp. previously recorded from epinephelines are parasites of species of Epinephelus and Mycteroperca; this is the first species from a species of Variola.

The parasite fauna of the chub mackerel Scomber japonicus Houtuym, 1782 was studied from the neritic areas of Morocco, Western Sahara, Mauritania and from the banks of the Azores Archipelago (the Great Meteor Bank, the Hyeres Bank and the Irving Bank) in 1994-2001. Twenty eight species of parasites of following group have been were found: Coccidia (1 species), Microsporidia (1), Myxosporea (4), Monogenea (4), Cestoda (5), Trematoda (5), Acanthocephala (1) and Nematoda (6). The differences between mackerel parasite fauna in the neritic areas and from of the Azores Archipelago banks were established. Peculiarities of the mackerel parasite fauna in two areas (Morocco--Western Sahara and Mauritania) corroborate the hypothesis that two populations of chub mackerel are available: "Sahara-Moroccan" and "Senegal-Mauritanian". Ontogenetic variability of parasite fauna was related to food demands of mackerel and its feeding habits in the areas Morocco and Mauritania. Kudoa histolytica has negative influence on the commercial value of S. japonicus. These parasites were localized in the muscles of mackerel from Mauritania (40%, TL = 20-25 cm). Parasites being dangerous for human health were presented by larvae of Bolbosoma sp. (occurred on the banks of the Azores Archipelago), Anisakis simplex and Contracaecum sp. (occurred in all areas investigated).

The first geographical records of five alien monogeneans for Italy is reported. Four species have been detected from Lepomis gibbosus (Linnaeus, 1758): Actinocleidus recurvatus Mizelle et Donahue, 1944, Actinocleidus oculatus (Mueller, 1934), Urocleidus similis (Mueller, 1936) and Urocleidus dispar (Mueller, 1936); one species from Silurus glanis Linnaeus, 1758: Thaparocleidus vistulensis (Siwak, 1932) n. comb.

Diplectanum monticellii n. sp. is described from the gills of Cynoscion leiarchus, a marine Sciaenidae, from Itacuruçá, Rio de Janeiro (type locality); Baía de Guaratuba, Paraná; and Pontal do Sul, Paraná in Brazil. The new species is characterized by the following features: bell-shaped male copulatory organ with a sleevelike base, accessory piece absent, vas deferens looping left intestinal cecum, vaginal aperture sinistroventral, and ventral anchor with elongate superficial and deep roots.

A new species of Sprostoniella is described from the gills of Chaetodipterus zonatus in Chamela Bay, on the west coast of Mexico. The new species differs from the 2 previously described congeners by having smaller testes each of which is not nearly as long as the ovary. It further differs from the type species, Sprostoniella multitestis, by having a poorly developed pair of accessory sclerites and the cecal diverticula are not confluent posteriorly. The new species also differs from Sprostoniella micrancyra, the other species of the genus, by having a shorter peduncle, the glands of Goto are smaller than the testes and ovary, and by having a slightly different haptoral structure, with 1 pair of hamuli rather than 2 pairs, and 1 central haptoral loculus instead of 2 loculi.

A total of 2,571 of the copepod Caligus epidemicus Hewitt from the yellow-fin bream, Acanthopagrus australis Günther, was examined for udonellids. Calinella myliobati Guberlet, 1936 was found on 3.3% of male copepods and 10.1% of female copepods. A new combination, Udonella myliobati (Guberlet, 1936) is proposed and its description emended. It differs from the type species Udonella caligorum Johnston, 1835 (as described by Price [1938]) in having a short egg filament and a median genital aperture. Only 1 of 102 chalimus larvae was infected, by a single adult worm. Juvenile udonellids common on mature copepods, were not found on any of the chalimus larvae. The highest number of U. myliobati (Guberlet, 1936), including hatching and unhatched eggs on 1 copepod, was 159. Adult and juvenile worms were attached mainly along the margins of the carapace and to the genital complex, whereas the majority of the eggs were attached to the ventral surface of the genital complex. The transfer of an adult worm from a male copepod to a female copepod was observed while the copepods were copulating. The large number of udonellids on a small population of mostly female copepods from the Brisbane River suggested that this was an aging population of copepods compared to the copepods collected from a semi-enclosed pond.