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Purpose: Studies on monogeneans parasitizing representatives of Siluriformes in Africa remain scarce and fragmentary. In order to contribute to fill this gap, we screened Heterobranchus longifilis from the Lindi River in the Democratic Republic of the Congo., Methods: Heterobranchus longifilis was purchased from fishermen in DR Congo, province of Tshopo, in Kisangani town, the Lindi River. The monogeneans were individually isolated from the gill and transferred directly onto a slide in a drop of Hoyer's medium., Results: Quadriacanthus lindiensis n. sp. is morphologically similar to Quadriacanthus longifilisi. However, it is distinguished from the latter by its non-sclerotized vagina, its dorsal cunei shape and the size of its bars., Conclusion: Only Q. lindiensis n. sp. was found on the gills of the single individual of H. longifilis screened. In the future, a representative sampling should enable us to verify if Q. lindiensis n. sp. co-occurs with other species known to parasitize H. longifilis., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Introduction: The present study describes three new dactylogyrid species infecting the gill filaments of cichlid fishes (Cichliformes: Cichlidae) from the Amazon basin, Peru: Sciadicleithrum amazoniensis n. sp. on Biotodoma cupido (Heckel, 1840), and Sciadicleithrum feliciajaramae n. sp. and Sciadicleithrum souzatecci n. sp. on Bujurquina peregrinabunda Kullander, 1986., Materials and Methods: Some monogeneans were stained with Gomori's trichrome and mounted in Canada Balsam to determine internal soft structures. Others were cleared in Hoyer's medium for the study of sclerotized structures. Drawings were made using a drawing tube and a microprojector., Results: Sciadicleithrum amazoniensis n. sp. is characterized by the presence of a male copulatory organ (MCO) with a coil of approximately 2 counterclockwise rings, an accessory piece articulated to base of the MCO with an expanded proximal end and a bifurcated distal end, and a sinistral vaginal aperture. Sciadicleithrum feliciajaramae n. sp. can be differentiated from all its congeners by its J-shaped MCO with about half a counterclockwise loop and a rod-shaped accessory piece articulated to the base of the MCO, with the distal end bent. Sciadicleithrum souzatecci n. sp. differs from all other members of Sciadicleithrum by having an elongated MCO with about a clockwise loop and a funnel-shaped base. Additionally, Sciadicleithrum souzatecci n. sp. is characterized by its weakly sclerotized, C-shaped accessory piece with a robust middle process., Conclusions: Present findings are added to the other 26 species previously known in Sciadicleithrum.This is the first data on the parasites of B. peregrinabunda., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Three new species of Gyrodactylus are described from three species of bitterling in Donghu Lake, China: Gyrodactylus ocellorhodei n. sp. from Rhodeus ocellatus; G. sinenorhodei n. sp. from Rhodeus sinensis; and G. acheilorhodei n. sp. from Acheilognathus macropterus. All the three new species showed similar opisthaptor morphology, especially the marginal hooks: all had a slender and perpendicular sickle shaft, and flat sickle base with distinct heel and inner arch which was different from the G. rhodei-group species parasitic on bitterling. Multivariate analyses based on hamulus and marginal hooks suggested that these three new species cannot be completely distinguished, despite some morphology divergence observed in certain less reliable morphometric features, such as hamulus root length, ventral bar total length and process shape. These three new species shared an identical 18S ribosomal RNA gene sequence, while the variation in the Internal Transcribed Spacers (ITS1-ITS2) sequence among them (8.4-11.2%, K2P) far exceeded the 1% ITS sequence difference that had been suggested as a threshold for species delimitation of Gyrodactylus. Phylogenetic analysis based on ITS1-ITS2 showed that all these sequenced Gyrodactylus spp. parasitic on the subfamily Acheilognathinae host formed a monophyletic group. However, a clear differentiation (18.9-20.9%, K2P of ITS1-ITS2) could be found between the subgroup from China (G. ocellorhodei n. sp., G. sinenorhodei n. sp. and G. acheilorhodei n. sp.) and that from Europe (G. rhodei)., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

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.)

Introduction: Two new dactylogyrid monogeneans, Anacanthorus cultro n. sp. and Notozothecium palometae n. sp., are described based on specimens collected from the gill filaments of Mylossoma albiscopum (Cope, 1872) (Characiformes: Serrasalmidae), a pelagic and herbivore teleost collected in the Tigre river, Loreto, Peru., Materials and Methods: Some monogeneans were stained with Gomori's trichrome and mounted in Canada Balsam to determine internal soft structures. Others were cleared in Hoyer's medium for the study of sclerotized structures. Drawings were made using a drawing tube and a microprojector., Results: Anacanthorus cultro n. sp. is characterized by the presence of a rod-shaped male copulatory organ (MCO) lacking featherlike structures, and a knife-shaped accessory piece with a submedial knob. Notozothecium palometae n. sp. can be distinguished from all congeners by its MCO with a subbasal spur and an accessory piece with inverted hammer shaped., Conclusions: This is the first data on the parasites of M. albiscopum, a popular fish in local markets. Anacanthorus cultro n. sp. is the twenty-fifth documented species of the genus in Peru, while N. palometae n. sp. represents the seventh species of the genus known to infect freshwater fish species in Peru., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

African cichlids are model systems for evolutionary studies and host-parasite interactions, because of their adaptive radiations and because they harbour many species of monogenean parasites with high host-specificity. Five locations were sampled in southern Lake Victoria: gill-infecting monogeneans were surveyed from 18 cichlid species belonging to this radiation superflock and two others representing two older and distantly related lineages. We found one species of Gyrodactylidae, Gyrodactylus sturmbaueri Vanhove, Snoeks, Volckaert & Huyse, 2011, and seven species of Dactylogyridae. Four are described herein: Cichlidogyrus pseudodossoui n. sp., Cichlidogyrus nyanza n. sp., Cichlidogyrus furu n. sp., and Cichlidogyrus vetusmolendarius n. sp. Another Cichlidogyrus species is reported but not formally described (low number of specimens, morphological similarity with C. furu n. sp.). Two other species are redescribed: C. bifurcatus Paperna, 1960 and C. longipenis Paperna & Thurston, 1969. Our results confirm that the monogenean fauna of Victorian littoral cichlids displays lower species richness and lower host-specificity than that of Lake Tanganyika littoral cichlids. In C. furu n. sp., hooks V are clearly longer than the others, highlighting the need to re-evaluate the current classification system that considers hook pairs III-VII as rather uniform. Some morphological features of C. bifurcatus, C. longipenis, and C. nyanza n. sp. suggest that these are closely related to congeners that infect other haplochromines. Morphological traits indicate that representatives of Cichlidogyrus colonised Lake Victoria haplochromines or their ancestors at least twice, which is in line with the Lake Victoria superflock being colonised by two cichlid tribes (Haplochromini and Oreochromini)., (© T.P. Gobbin et al., published by EDP Sciences, 2024.)

Herein, we describe several newly-collected specimens of Neopolystoma cf. orbiculare from the urinary bladder of 2 alligator snapping turtles, Macrochelys temminckii (Troost in Harland, 1835) (Cryptodira: Chelydridae Gray, 1831) from Comet Lake (30°35'46.94″N, 88°36'3.12″W), Pascagoula River, Mississippi. Our specimens differed from all previous descriptions of N. orbiculare and its junior subjective synonyms by the combination of having intestinal ceca adorned with triangular pockets and that terminate dorsal to the haptor, distinctive hooklets each having a handle and guard of approximately equal length and having a much longer and curved blade, 16 genital coronet spines that each possess 1-2 flanges per spine, pre-testicular vaginal pores, and vaginal ducts that are anterior to the junction of the oviduct and genito-intestinal canal. Some of our specimens were enantiomorphic (4 and 3 had a dextral and sinistral ovary, respectively). Nucleotide sequences (large subunit ribosomal DNA [28S], small subunit ribosomal DNA [18S], and cytochrome oxidase subunit 1 mitochondrial gene [COI]) for our specimens were most similar to GenBank sequences ascribed to N. orbiculare. Single-gene and concatenated phylogenetic analyses confirmed that NeopolystomaPrice, 1939 is polyphyletic and that our isolates share a recent common ancestor with those ascribed to N. orbiculare. This is the first record of a polystomatid from Mississippi, from the Pascagoula River, and from the alligator snapping turtle (and only the second species of Neopolystoma reported from any snapping turtle)., (© American Society of Parasitologists 2021.)

A new species of monogenean, Dactylogyrus pisolabrae n. sp., was found parasitizing the gills of the Pealip Redhorse, Moxostoma pisolabrum, from Oklahoma. Dactylogyrus pisolabrae is morphologically similar to Dactylogyrus apos, Dactylogyrus atripinnei, Dactylogyrus duquesnei, and Dactylogyrus niger, all parasitizing other species of suckers, by possessing a robust, sickle-shaped male copulatory organ, but differs from these and all other species of North American Dactylogyrus by possessing 2 unique wing-like projections opposite each other on the proximal portion of the accessory piece. Dactylogyrus pisolabrae represents the first monogenean reported from the Pealip Redhorse.

Three piranha species, Serrasalmus maculatus, S. marginatus and Pygocentrus nattereri, living sympatrically in the lower Paraná River (Argentina) were examined searching for nasal monogeneans to know its diversity and distribution. Four species of monogeneans belonging to Rhinoxenus were found parasitizing the nasal cavities. Two new species are described, and new morphological data of 2 previously described species is provided. Rhinoxenus argentinensis n. sp. is characterized by having the male copulatory organ (MCO) as a coiled tube with a reel shaped-base; an elongated accessory piece articulated to base of MCO; a sinistral vagina with a sclerotized vestibule, and a sclerotized cap of the ventral anchor laterally modified forming a triangular expansion. Rhinoxenus paranaensis n. sp. is characterized by having a MCO as a coiled tube with a reel-shaped base; an accessory piece with an elongate proximal portion, a dilated distal portion with digitiform projections articulated to base of MCO; a sinistral vagina with 5-6 cuticular spine-shaped processes, and a sclerotized cap of the ventral anchor modified laterally forming a bilobate expansion. Additionally, multivariate discriminant analyses showed significant morphometric differences in the ventral anchors among Rhinoxenus species parasitizing 'piranhas '.

Eating raw or insufficiently cooked mollusks is a known risk factor for human echinostomiasis. We confirmed identification of Artyfechinostomum sufrartyfex trematodes as the causative agent of disease among 170 children in northern Bihar, India. We also identified the snail Pila globosa as a potential source of infections in the study area.

Aphanoblastella magna n. sp. is described from the gills of the heptapterid catfish Pimelodella avanhandavae Eigenmann, 1917 in southeastern Brazil (Paraná River Basin). This new species most closely resembles Aphanoblastella chagresii Mendoza-Franco, Aguirre-Macedo and Vidal-Martínez, 2007 described from a congeneric fish host in Panama, but can be distinguished by the shape of the accessory piece and shape and size of the ventral and dorsal bars. From the other species of the genus, A. magna n. sp. differs mainly in the shape of the male copulatory organ (MCO), which is sinuous, versus spirally coiled in other species of the genus, except for A. travassosi (Price, 1938), and by the accessory piece which resembles a 'shoehorn'. Aphanoblastella magna n. sp. is the seventh species of the genus and the first dactylogyrid described from P. avanhandavae. A partial 28S rDNA gene sequence of the new species is also provided; it forms a monophyletic clade with two congeners for which molecular data are available.

Samples of Gyrodactylus fairporti Van Cleave, 1921 from young-of-the-year black bullhead (Ameiurus melas) stranded in riverside pools of the Black River (La Crosse County,) WI, USA, are used to supplement the species diagnosis, including new details on the marginal hook sickles, the male copulatory organ (MCO), and 18S rRNA gene sequence data. The anchors of G. fairporti are relatively long and thin, 58.2 ± 1.2 μm in length; roots 15.5 ± 1.0 μm; shaft 38.1 ± 1.5 μm; point 31.3 ± 1.5 μm. The ventral bar is 19.4 ± 0.4 μm wide and 5.7 ± 0.9 μm long, with small anterolateral processes, 2.0 ± 0.6 μm long, and an almost rectangular posterior shield 15.5 ± 1.1 μm in length. The marginal hooks are 29.2 ± 1.0 μm long, with the handle 23.9 ± 1.2 μm in length. These measurements are similar to those reported from Iowa and Alabama, with the additional observation of the anchor point bending outwardly halfway along its length. The marginal hook sickle blade leaves the base angled ventrally away from the longitudinal axis; the sickle point is short; the toe has a rounded shelf and the heel is small, thin, and rounded. The MCO has eight small spines, two large ones laterally and the others of various lengths, with two of the smallest spines being slightly out-of-line compared with all the others. The taxonomy of G. fairporti is compared to Gyrodactylus ictaluri Rogers, 1967 and G. nebulosus Kritsky & Mizelle, 1967, the other two species known from captive and wild ictalurids endemic to North America. The three species all have a relatively compact ventral bar with short anterolateral processes, a short almost rectangular ventral bar membrane, an MCO with up to eight small spines of varying length, and a hook sickle angled ventrally. Diagnostically, the species are readily identified by the total length and shape of the anchors. G. fairporti bears the longest (53-65 μm) and most slender anchors of the trio, G. nebulosus intermediate (49-51 μm) and G. ictaluri with the shortest and stoutest (40-45 μm) of these species. A BLAST search of a partial (413 bp) 18S rRNA gene showed the highest similarity with Gyrodactylus sp. reported from Ameiurus nebulosus (Siluriformes) in Ontario.

The ornamental fish trade provides a pathway for the global translocation of aquatic parasites. We examined a total of 1020 fish imported from Singapore, Malaysia, Thailand, or Sri Lanka to Australia (including freshwater and marine fish species) for monogenean ectoparasites. Fish were received following veterinary certification that they showed no clinical signs of pests and diseases from the exporting country and visual inspection at Australian border control. Australian import conditions require mandatory treatment for goldfish with parasiticides (e.g. trichlorfon, formaldehyde, sodium chloride) for the presence of gill flukes (Dactylogyrus vastator Nybelin, 1924 and Dactylogyrus extensus Mueller and Van Cleave, 1932) prior to export. Over 950 individual parasites were detected in five imported fish species, representing 14 monogenean species. Seven Dactylogyrus spp. including D. vastator and three Gyrodactylus spp. infected goldfish, Carassius auratus Linnaeus, 1758, from Malaysia, Singapore, and Thailand. Dactylogyrus ostraviensis Řehulka, 1988, infected rosy barb, Pethia conchonius Hamilton, 1822, from Singapore, Sri Lanka, and Thailand while two Trianchoratus spp. infected three spot gourami, Trichopodus trichopterus Pallas, 1970 and pearl gourami Trichopodus leerii Bleeker, 1852, from Sri Lanka. Urocleidoides reticulatus Mizelle & Price, 1964, infected guppy, Poecilia reticulata Peters, 1859, from Sri Lanka. The discovery of D. vastator in goldfish, as well as 13 other monogenean species, shows that pre-export health requirements, which include chemical treatment of goldfish, and inspection of all ornamental fish species did not prevent infection by monogeneans. Inspection prior to exportation and at border control must account for the highly cryptic nature of monogenean parasites and consider alternatives to current pre-export conditions and visual inspection at border control.

The Lower Congo Basin is characterized by a mangrove-lined estuary at its mouth and, further upstream, by many hydrogeographical barriers such as rapids and narrow gorges. Five localities in the mangroves and four from (upstream) left bank tributaries or pools were sampled. On the gills of Coptodon tholloni, Coptodon rendalli, Hemichromis elongatus, Hemichromis stellifer and Tylochromis praecox, 17 species of parasites (Dactylogyridae & Gyrodactylidae, Monogenea) were found, eight of which are new to science. Six of these are herein described: Cichlidogyrus bixlerzavalai n. sp. and Cichlidogyrus omari n. sp. from T. praecox, Cichlidogyrus calycinus n. sp. and Cichlidogyrus polyenso n. sp. from H. elongatus, Cichlidogyrus kmentovae n. sp. from H. stellifer and Onchobdella ximenae n. sp. from both species of Hemichromis. On Cichlidogyrus reversati a ridge on the accessory piece was discovered that connects to the basal bulb of the penis. We report a putative spillback effect of the native parasites Cichlidogyrus berradae, Cichlidogyrus cubitus and Cichlidogyrus flexicolpos from C. tholloni to the introduced C. rendalli. From our results, we note that the parasite fauna of Lower Congo has a higher affinity with the fauna of West African and nearby freshwater ecoregions than it has with fauna of other regions of the Congo Basin and Central Africa., (© M.W.P. Jorissen et al., published by EDP Sciences, 2018.)

Mycteronastes Kearn and Beverley-Burton, 1990 (Monogenoidea: Monocotylidae: Merizocotylinae) was resurrected from subjective synonymy with Merizocotyle Cerfontaine, 1894 , and its diagnosis was emended to include monocotylids with a haptor lacking a central loculus and having 5 peripheral (2 bilateral pairs and an unpaired anteromedial loculus), 1 interhamular, and 17 marginal loculi. The 3 species of Mycteronastes accepted herein are parasitic within the olfactory sacs of rays and sawfishes: Mycteronastes icopae ( Beverley-Burton and Williams, 1989 ) Kearn and Beverley-Burton, 1990 (type species) from the giant shovelnose ray, Glaucostegus typus (Anonymous (Bennett)) (Glaucostegidae), in the southwestern Pacific Ocean; Mycteronastes undulatae Kearn and Beverley-Burton, 1990 from the undulate ray, Raja undulata Lacepède (Rajidae), in the northeastern Atlantic Ocean; and Mycteronastes caalusi n. sp. from the smalltooth sawfish, Pristis pectinata Latham (Pristidae), in the Gulf of Mexico. Mycteronastes caalusi is most easily differentiated from its congeners by the combination of having 2 median cephalic papillae, an oval haptor that is wider than the body proper and lacks a deeply scalloped margin, a comparatively large anteromedial peripheral loculus, an unsclerotized male copulatory organ that is wholly anterior to the vaginal pores, a relatively small distal portion of the uterus (ootype chamber) that is mostly anterior to the vaginae, and a delicate uterus. The present study is the first report of a monocotylid from the olfactory sacs of P. pectinata and the first record of a species of Mycteronastes from the Gulf of Mexico. Notes on the taxonomy and systematics of some species assigned to Calicotyle Diesing, 1850 (Monocotylidae: Calicotylinae) are included.

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.

Background: African catfishes of the families Bagridae and Clariidae are known to be parasitized with monogeneans of Quadriacanthus Paperna, 1961 (Dactylogyridae). The genus remains taxonomically challenging due to its speciose nature and relatively wide host range representing two fish orders, i.e. Siluriformes and Osteoglossiformes, in Africa and Asia. Here, we investigated diversity of Quadriacanthus spp. parasitizing Clarias gariepinus (Burchell), Heterobranchus bidorsalis Geoffroy Saint-Hilaire, and Bagrus docmak (Forsskål) collected in the Lake Turkana (Kenya) and Nile River Basin (Sudan). The interspecific relationships among Quadriacanthus spp. parasitizing catfishes inferred from ribosomal DNA sequences were investigated for the first time., Methods: A combined morphological and molecular approach was used for description of the new species and for a critical review of the previously described Quadriacanthus spp., by means of phase contrast microscopic examination of sclerotized structures, and assessing the genetic divergence among the species found using rDNA sequences., Results: Seven species (including four new) of Quadriacanthus were identified. These were as follows: Quadriacanthus aegypticus El-Naggar & Serag, 1986, Quadriacanthus clariadis Paperna, 1961, Quadriacanthus fornicatus n. sp., Quadriacanthus pravus n. sp., and Quadriacanthus zuheiri n. sp. from Clarias gariepinus (Clariidae); Quadriacanthus mandibulatus n. sp. from Heterobranchus bidorsalis (Clariidae); and Quadriacanthus bagrae Paperna, 1979 from Bagrus docmak (Bagridae). For both 18S-ITS1 and 28S rDNA regions, Q. clariadis from a clariid fish was found to be most closely related to Q. bagrae from a bagrid host. Quadriacanthus mandibulatus n. sp. was observed to be the most distant species from the others. The separation of Q. mandibulatus n. sp. from the other species corresponds with the different morphology of its copulatory tube. The copulatory tube is terminally enlarged in Q. mandibulatus n. sp., while the tube in all other congeners studied is comparatively small and with an oblique tapering termination., Conclusions: This study contributes to a better understanding of African dactylogyrid diversity and provides the first molecular characterization of Quadriacanthus spp. The observed interspecific genetic relationships among Quadriacanthus spp. from clariids and Q. bagrae from a bagrid host suggest a possible host-switching event in the evolutionary history of the genus. Our records extend the currently known geographical range for Quadriacanthus spp. to Kenya and Sudan.

Three species of genus Bychowskyella Akhmerov (1952), i.e. B. fossilisi Majumdar & Agarwal, 1989, B. tchangi Gusev, 1976 and B. wallagonia (Jain, 1959a) Gusev, 1961, were found to parasitize the gill filaments of siluriform fish in India. This redescription based on light microscopic examination of B. fossilisi, B. tchangi and B. wallagonia provides detailed taxonomic data for these species. We also amplified the 18S ribosomal RNA gene to evaluate the phylogenetic relationships of these three species. The morphological and genetic profiles confirmed the validation and taxonomical relationships of the above-mentioned species belonging to the genus Bychowskyella.

Monocotyle luquei n. sp. (Monogenea: Monocotylidae) was described from gills of diamond stingray Dasyatis dipterura (Jordan and Gilbert, 1880) (Dasyatidae) off Peru. The new species can be differentiated from the other species of the genus by the combination of the following characteristics: (1) accessory sclerites on the dorsal posterior surface of the body absent, (2) only one testis is present, (3) 1-2 loops in the copulatory organ, (4) the male copulatory organ with a sclerotized accessory piece, (5) shape of five sclerites in marginal papillae, (6) size of anchor and (7) posterolateral septa bifurcated. This is the first record of species of Monocotyle Taschenberg, 1878 from the southern Pacific.

Two new species of Sciadicleithrum Kritsky, Thatcher and Boeger, 1989 are described from two cichlids from the Araguarí River, State of Amapá, northern Brazil. Sciadicleithrum edgari n. sp. from Satanoperca jurupari (Heckel, 1840) differs from all congeneric species in the morphology (hook-shaped, with middle process and distally bifurcate) of the accessory piece of the male copulatory organ (MCO). Sciadiclethrum araguariensis n. sp. from Crenicichla labrina (Spix and Agassiz, 1831) can be distinguished from all other species by a Y-shaped accessory piece of MCO. In addition to the description of two new species, new host and geographical records of six dactylogyrid monogeneans from cichlid fishes are presented.

Gyrodactylus parasite infected juveniles on rainbow trout Oncorhynchus mykiss (Walbaum, 1792) from a fish farm in Lake Ladoga were investigated. The observed cases of infection in fish featured a high prevalence, when almost all of the fish were infected. However, if an outbreak of the monogenean infection is observed in spring, the intensity of the infection may be low, and when the infection occurs in the ice-covered period (late autumn - winter), the number of parasites on the fins of a single fish may exceed 3000 specimens. Molecular identification of the parasite demonstrated that the infecting clone was identical with rainbow trout specific strain of Gyrodactylus salaris RBT widely spread in Northern Europe, but a small proportion of the parasites were the hybrid clone Gyrodactylus pomeraniae x G. lavareti. Morphological variations of hooks and other opisthaptor parts in the monogenean Gyrodactylus depending on the intensity of infection in rainbow trout were demonstrated.

Triloculotrema euzeti n. sp. (Monogenea, Monocotylidae, Merizocotylinae) is described from the nasal tissues of the blackspotted smooth-hound Mustelus punctulatus collected from the coastal marine waters off Tunisia. The new parasite species is distinguished from the other two species of the genus, T. japanicae Kearn, 1993 and T. chisholmae Justine, 2009, by the morphology of the sclerotised male copulatory organ which has longitudinal ridges. The species is also characterised by its oötype with short descending and ascending limbs (long and more convoluted in the other two species). The presence of three peripheral loculi, which is the main characteristic of the genus Triloculotrema Kearn, 1993, is unconfirmed. This is the first description of a species of this genus in the Mediterranean Sea and the first record from a coastal shark., (© L. Boudaya & L. Neifar, published by EDP Sciences, 2016.)

A previously undescribed species of Entobdella is reported from the skin of the Greenland halibut, Reinhardtius hippoglossoides (Pleuronectiformes, Pleuronectidae). Entobdella whittingtoni sp. nov. differs from other species of Entobdella, including skin parasites of the related pleuronectids Hippoglossus hippoglossus (Atlantic halibut) and H. stenolepis (Pacific halibut), in lacking papillae on the ventral surface of the haptor. Other characteristics of E. whittingtoni are as follows: the absence of vitelline follicles lateral to the pharynx thereby exposing gut caeca in this region of whole mounts; the presence of a circular feature of unknown function, resembling a rosette in sections, attached to the wall of the internal male accessory reservoir; the lack of eyes. Papillae are also absent from the ventral surface of the haptor of the gill-parasitic entobdelline Branchobdella pugetensis, a gill parasite of the pleuronectid Atheresthes stomias. This raises the question as to whether this gill parasite has evolved from a skin-parasitic ancestor similar to E. whittingtoni. An answer to this question requires a more detailed study of the male reproductive apparatus of B. pugetensis and the use of molecular techniques to explore the relationship between B. pugetensis and E. whittingtoni.

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.)

Most animals are concurrently infected with multiple parasites, and interactions among them may influence both disease dynamics and host fitness. However, the sublethal costs of parasite infections are difficult to measure and the effects of concomitant infections with multiple parasite species on individual physiology and fitness are poorly described for wild hosts. To understand the costs of co-infection, we investigated the relationships among 189 European eel (Anguilla anguilla) from Mar Menor, parasites (richness and intensity) and eel's 'health status' (fluctuant asymmetry, splenic somatic index and the scaled mass index) by partial least squares regression. We found a positive relationship with 44% of the health status variance explained by parasites. Contracaecum sp. (Nematoda: Anisakidae) was the strongest predictor variable (44·72%) followed by Bucephalus anguillae (Platyhelminthes: Bucephalidae), (29·26%), considered the two most relevant parasites in the analysis. Subsequently, 15·67 and 12·01% of the response variables block were explained by parasite richness and Deropristis inflata (Platyhelminthes: Deropristiidae), respectively. Thus, the presence of multiple parasitic exposures with little effect on condition, strongly suggests that eels from Mar Menor tolerate multiparasitism.

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.

The rumen parasite, Gastrothylax crumenifer (Platyhelminthes: Gastrothylacidae), is a highly pathogenic trematode parasite of goat (Capra hircus). It sucks blood that causes acute disease like anemia, and severe economic losses occur due to morbidity and mortality of the ruminant infected by these worms. The study of these rumen paramphistomes, their infection, and public health importance remains unclear in India especially in the western part of state Uttar Pradesh (U.P.), Meerut, India, where the goat meat consumption is very high. This paper provides the molecular characterization of G. crumenifer recovered from the rumen of Capra hircus from Meerut, U.P., India by the partial sequence of 28S rDNA. Nucleotide sequence similarity searching on BLAST of 28S rDNA from parasites showed the highest identity with those of G. crumenifer from the same host Capra hircus. This is the first report of molecular identification of G. crumenifer from this part of India.

Baseline information on parasitic infections, including monogenean infections on wild fishes, may aid in implementation of proactive measures as opposed to reactive research aimed at crisis control with reference to future aquaculture applications. The aim of this project was to examine the freshwater monogenean fauna of the Vaal Dam, Vaal River system, South Africa. This short communication reports on infection statistics for monogenean species, some representing new locality records. Parasites were collected from host species other than Labeo spp. from the Vaal Dam, during a summer (January 2010) survey. Fish collected using gill nets of varying mesh sizes were weighed and measured. Mucous smears were prepared from the skin and fins with the aid of microscope slides. Fish were killed humanely by severing the spinal cord behind the head. Gills were carefully removed and divided into areas which were separately scraped to investigate potential parasite site preference. The areas examined were dorsal, median and ventral positions on both the anterior and posterior hemibranch. Both mucous smears and gill scrapings were examined with the aid of a stereo microscope. More parasites were collected from the first or second gill arches, the medial position on the gill, and the anterior hemibranch. Preference for either left or right gill set was inconclusive. Spatial distribution of parasites is thought to result from water flow over the gills during respiration. This paper reports a new locality record for the following monogenean species: Quadriacanthus aegypticus, Dactylogyrus extensus, Dactylogyrus minitus, Gyrodactylus kherulensis and Dactylogyrus lamellatus.

Two new Dactylogyrus spp., D. angorae and D. turcicus have been described from the gills of the endemic cyprinid fishes, Capoeta angorae and C. mauricii from the Anatolian Region of Turkey. The shape of the anchors, hooks and the copulation organ of both species differ from those of the Dactylogyrus spp. found on other Capoeta species known from the Ponto-Caspian and Tigris-Euphrates regions.

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.

Madapolystoma ramilijaonae n. sp. and Madapolystoma cryptica n. sp. (Monogenea, Polystomatidae) are described from the urinary bladder of disjunct populations of the Madagascar shrub frog Guibemantis liber. Although only minor morphological characters distinguish the new species from the single nominal species of the genus, i.e. Madapolystoma biritika, their strong and concordant differentiation in a mitochondrial and a nuclear gene supplemented by phylogenetic analyses indicates that M. ramilijaonae n. sp. and M. cryptica n. sp. should be regarded as two distinct species. Because anuran polystomes are known to be host-specific, the description of two cryptic species from a single host species points to a taxonomic complex situation in G. liber, a widespread frog that is characterized by the presence of several deep conspecific lineages and possibly by hybridization and admixture with other species of Guibemantis., (© 2013.)

A new species of Hexabothriidae, Mobulicola enantiomorphica n. gen., n. sp., is described on the basis of specimens collected from the gill of a lesser devil ray, Mobula hypostoma (Bancroft, 1831) (Rajiformes: Mobulidae), captured in the northern Gulf of Mexico (30°13'49.22″N, 88°20'31.69″W) off Dauphin Island, Alabama. We also herein redescribe Mobulicola dubium (Euzet and Maillard, 1967) n. comb. on the basis of the holotype (36HG-69-1) and paratypes (36HG-69-2 and 36HG-69-3) collected from the gill of a lesser Guinean devil ray, Mobula rochebrunei (Vaillant, 1879), captured in the eastern Atlantic Ocean off the island of Gorée (14°40'02.26″N, 17°23'4.96″W), Senegal. Mobulicola has the following combination of diagnostic features that differentiate it from other hexabothriid genera: haptor symmetrical; vasa efferentia narrow for entire length (not dilated distally), glandular-walled, joining medially immediately anterior to testicular field; vas deferens glandular for part or all of length and extensively convoluted; male copulatory organ massive, oblong, unarmed, dilated for entire length, lacking prostatic region; seminal receptacle present; ootype lacking longitudinal rows of large cells (ootype côtelé); vaginae parallel, with well-differentiated proximal (narrow, tube-like) and distal (laterally expanded, musculoglandular) portions; uterine eggs with 2 elongate filaments. Mobulicola is morphologically most similar to Branchotenthes Bullard and Dippenaar, 2003 but differs from it by the combination of having short, delicate vasa efferentia that are narrow for their entire length and that each extends slightly anteriad from the testicular field before uniting medially, a vas deferens that is convoluted between the common vitelline duct and male copulatory organ, an ovate, compact seminal receptacle, an ovary that ascends, descends, then ascends, and a proximal uterus that is extensively convoluted posterior to the male copulatory organ. The new species differs from M. dubium by the combination of having a proportionally shorter sclerite hook (19-29% of sclerite shaft total length), a vas deferens that is glandular-walled and laterally expanded proximally and nonglandular and narrow distally, and a common vitelline duct with dextral and sinistral loops extending anteriad. This is only the second report of a hexabothriid from a mobulid and the first report of a monogenoid from Mobula hypostoma.

A novel and easily constructed apparatus for collecting monogenean eggs released by the parasites into the water is described and illustrated. Use of this technique may lead to a better understanding of the parasite's biology, which, in turn, may lead to the improvement of parasite management strategies in fish farms where monogeneans are potentially harmful to their hosts. The technique is also useful for studies of eggs or free-living stages of other fish parasites., (Copyright © 2013 Elsevier Inc. All rights reserved.)

A high infestation of the monogenean Gussevia tucunarense in a cultivation of bujurqui-tucunare was reported. The prevalence was 100%. The mean intensity and abundance of the parasite was 164.4 of parasites per individual. This is the first report of a high infestation by G. tucunarense in C. semifasciatus cultured from the Peruvian Amazon.

An aquaculture research facility experienced high mortality rates in white bass Morone chrysops associated with a monogenean infestation of the gills, but not in striped bass Morone saxatilis in the same facility. All mortalities had pale gills. Monogeneans, identified as Gamacallum macroura (MacCallum and MacCallum 1913) Unnithan 1971, were found on the gills. Pale-gilled and healthy white bass were selected with no particular attention to condition for venipuncture and euthanasia for postmortem examination, including parasite counts from gills. The median packed cell volume (PCV) of fish with gill pallor was 12.5% (range 9-37%) while PVC of fish with more normal color was 30% (27-33%). Association between the PCV and gill pallor score was statistically significant, as was the association between PCV and the number of monogeneans found on the gills of each fish. Median estimated white blood cell count of fish with gill pallor, at 12.05 × 10(3/)μL (range 3.8-24.7), was significantly lower than of apparently healthy fish: 24.7 × 10(3)/μL (17.3-31.5). Histopathology of the gill arches of pale-gilled fish revealed multifocal moderate to severe branchitis, focal areas of dilated hyperplastic lamellae occluded by fibrin, and monogeneans attached to the lamellae. Fish that were apparently healthy had grossly similar histologic lesions, but at lower frequency and severity.

With technological improvements in otolith microchemical analysis, the flexible use of habitat from coastal marine to fresh waters has been discovered in Japanese eels Anguilla japonica. We examined the occurrence of 3 congeneric gill monogeneans-Pseudodactylogyrus anguillae, P. bini, and P. kamegaii-on wild Japanese eels, in relation to the host's flexibility. From April 2008 to October 2009, 114 eels were collected from a brackish-water cove and 2 rivers flowing into the cove in Ehime Prefecture, western Japan. Based on otolith microchemical analysis, the eels were discriminated according to the following 4 types of habitat use: freshwater residents (Type I), individuals utilizing low-salinity habitats (Type II), downstream habitat-shifters (Type III), and cove residents (Type IV). P. anguillae occurred mainly on Type I and II eels, while P. bini was primarily found on Type I eels. In contrast, P. kamegaii occurred mainly on Type III and IV eels. Thus, we conclude that species composition and infection levels of Pseudodactylogyrus spp. clearly differed with habitat-use patterns of Japanese eels. Also, since P. anguillae was scarcely found on either Type III or IV eels, this study suggests that previous identifications of monogeneans collected from European brackish-water localities as P. anguillae may require verification.

The objectives of this study were twofold: to determine the sensitivity of gill biopsies used for the screening of Pseudodactylogyrus bini in subclinically infested American eels (Anguilla rostrata) and to evaluate the effect of bath anesthesia on the proportion of infested eels. Fifty-four eels were euthanized following either intracoelomic injection of T61 or deep anesthesia with tricaine methanesulfonate. Proportions of eels infested by P. bini diagnosed by gill biopsies taken through the gill slit and by microscopic examination of the entire gill arches were compared. The euthanasia protocol had no significant effect on parasite abundance. The prevalence of monogeneans detected by examination of nonterminal antemortem gill biopsies and by complete gill examinations was 20% and 70%, respectively. The sensitivity of gill biopsies (29%) to detect P. bini in subclinically infested eels is therefore low, and should be used for group screening rather than individual screening.

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.

Heterocotyle sulamericana n. sp. is described from the gills of Dasyatis guttata (Bloch & Schneider) caught off the coast of Brazil near Rio de Janeiro. This species can be distinguished from all other members of Heterocotyle Scott, 1904 by a combination of the morphology of the male copulatory organ, which is a short, slightly curved, sclerotised tube with no accessory piece, and the haptor, which has a single ridge surmounting all septa. This is the first Heterocotyle species to be described from the southwestern Atlantic.

Kankana manampoka n. gen., n. sp. (Monogenea, Polystomatidae), is described from the urinary bladder of the narrow-mouthed frog Platypelis pollicaris. This is the first record of a polystome from the Microhylidae and the third polystome genus from Madagascar, next to Metapolystoma and Madapolystoma. The extensive uterus and presence of hamuli resemble Metapolystoma but the vitellarium confined to the lateral fields in Kankana is different. Madapolystoma also has an extensive uterus but contain only up to 32 advanced developed larvae. Based on the extensive uterus filling the body proper and the vitellarium confined to two lateral fields posterior in the body this new polystome resembles Eupolystoma known from Africa and India. However, unlike Eupolystoma, the gonads are in the middle of the body, vaginae are lacking and a pair of hamuli is present. A molecular phylogenetic analysis of concatenated 18S and 28S ribosomal RNA gene sequences supplemented by genetic distances inferred from 28S and COI sequences showed that this new genus is more related to Madapolystoma, a genus only reported from Madagascar, than to Eupolystoma known from Africa and India and Metapolystoma known from Africa and Madagascar., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

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.

Prevalence and intensity of Gyrodactylus colemanensis and G. salmonis (Monogenea) parasitizing juvenile/adult brook trout Salvelinus fontinalis, rainbow trout Oncorhynchus mykiss, brown trout Salmo trutta, and Atlantic salmon Salmo salar at 3 localities over an 8 km stretch in the South River, Nova Scotia, Canada, were calculated 4 times over a 9 mo period (October 2009, December 2009, March 2010, June 2010). G. colemanensis was on all 4 salmonids (endemic and non-endemic), while G. salmonis parasitized mostly S. fontinalis (endemic) and occasionally S. trutta (non-endemic). At an upstream locality, beyond a waterfall barrier, in a small tributary of the main river, G. colemanensis was more common than G. salmonis. In the main river, 7 km downstream, prevalence of G. colemanensis on S. fontinalis was comparable, or higher, than that of G. salmonis, while intensity of G. salmonis was higher than that of G. colemanensis. Downstream a further 1 km, in a tributary of the main river, both prevalence and intensity of G. salmonis on brook trout were higher than those of G. colemanensis. Stocks at a local trout hatchery had only G. colemanensis. The present study reports on a method by which exit water from such farms can be monitored for gyrodactylid parasites through a simple settling procedure. We estimated that up to 230,000 dislodged, live G. colemanensis exit the hatchery daily in discharge water entering the river. It is suggested that such systems are ideal for studying the impact of such parasite export on the nature of local parasite populations.

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 an investigation of the biodiversity and structure of parasite communities among native populations of the erythrinid fish Hoplias malabaricus (Characiformes) from 7 rivers in Brazil, the following monogenoidean (Dactylogyridae) species were found: Urocleidoides malabaricusi n. sp., Urocleidoides naris n. sp., Urocleidoides cuiabai n. sp., Urocleidoides brasiliensis n. sp., and Urocleidoides eremitus Kritsky, Thatcher, and Boeger, 1986. Specimens considered as a new genus of Dactylogyridae were also found. The new species are mainly distinguished from the other 14 species of Urocleidoides in the general morphology of their copulatory and anchors/bar complexes. These new species and the new dactylogyrid genus are described, as well as supplemental observations and new illustrations of U. eremitus are provided. The present findings expand the known geographical distribution of species of Urocleidoides to southeastern and midwestern Brazil. A high speciation of this genus in the tropics is hypothesized, and it is briefly discussed.

Polystoma okomuensis is described as a new species of the Polystomatidae parasitic in the urinary bladder of Boulenger's striped frog Phlyctimantis boulengeri in the Okomu National Park, Edo State, Nigeria. Although other African polystomes have been reported from Nigeria, this is the first to be described from the country and the first from Phlyctimantis. It is distinguished from other African Polystoma species by a combination of characters, including the body size, size and shape of the hamuli, size and shape of marginal hooklets and intestinal location. Phlyctimantis boulengeri was found to be infected in two of four seasonal lakes where specimens were caught with prevalences and mean intensities ranging from 14.3 to 22% and 1.0 to 1.5, respectively. Of the total number of 45 frogs examined, the prevalence was 15.6% and mean intensity 1.4.

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.

Six new and 1 previously described species of Pseudorhabdosynochus (Diplectanidae) are described and/or reported from the gill lamellae of 5 serranid (Perciformes) fish species from the Pacific waters in Guerrero State of Mexico and Panama City, Panama. These species are Pseudorhabdosynochus guerreroensis n. sp. from the Pacific mutton hamlet Alphestes inmaculatus Breder (type host), rivulated mutton hamlet Alphestes multiguttatus (Günther), and spotted grouper Epinephelus analogus Gill from Mexico; Pseudorhabdosynochus urceolus n. sp. from the Pacific graysby Cephalopholis panamensis (Steindachner) from Taboga Island in Panama; Pseudorhabdosynochus spirani n. sp. from the starry grouper Epinephelus labriformis (Jenyns) from Mexico and the Perlas Archipelago and Taboga Island in Panama; Pseudorhabdosynochus fulgidus n. sp. from E. labriformis from Mexico and the Perlas Archipelago and Taboga Island (type locality) in Panama; Pseudorhabdosynochus tabogaensis n. sp. from E. labriformis from Mexico and the Perlas Archipelago and Taboga Island (type locality) in Panama; Pseudorhabdosynochus anulus n. sp. from E. labriformis from Mexico and Taboga Island (type locality) in Panama; and Pseudorhabdosynochus amplidiscatum (Bravo-Hollis, 1954) Kritsky and Beverley-Burton, 1986 from E. analogus and E. labriformis from Mexico and the Perlas Archipelago and Taboga Island in Panama. All new species are mainly distinguished from other species of the genus by the shape and size of the sclerotized vagina and haptoral structures. The present specimens of Alphestes, Cephalopholis, and Epinephelus spp. represent new host records and Panama represents a new geographic record for species of Pseudorhabdosynochus. The apparent common feature supporting a close similarity of these diplectanids is a single, secondary ejaculatory bulb with thickened wall.

Sparicotyle chrysophrii infections were highlighted during a parasitological monitoring carried out on cultured Gilthead sea bream Sparus aurata Linnaeus 1758 from aquaculture sites in Corsica. Factors and biological mechanisms regulating parasites populations, particularly controlling the infestation and survival of monogeneans have been studied. Variations in infection support the hypotheses that the main factor determining the infection of S. chrysophrii was temperature and that the parasite life cycle could be influenced by fish size and fish age. One hundred forty-nine of 280 S. aurata studied were infected. Seasonal differences in prevalence of infection were observed in all farms studied. A similar pattern was observed for parasite abundance with maximal infection levels occurring when water temperature were lower. A statistically significant dependence between infection and host size was also observed. The study of the surface topography of S. chrysophrii with scanning electron microscopy highlighted morphological adaptations not previously described. Parasites have developed diverse mechanisms of survival within the host that facilitate the establishment of infection. We mainly studied sensory structures and the anchoring systems of the parasite, i.e., filaments of eggs and haptor, enabling it to ensure the dispersal and survival of the species.

Various strains of Atlantic salmon exhibit different levels of susceptibility to infections with the ectoparasitic monogenean Gyrodactylus salaris. The basic mechanisms involved in this differential ability to respond to this monogenean were elucidated using controlled and duplicated challenge experiments. Highly susceptible East Atlantic salmon allowed parasite populations to reach up to 3000 parasites per host within 6 weeks, whereas less susceptible Baltic salmon never reached larger parasite burdens than 122 parasites per host during the same period. The present study, comprising immunohistochemistry and gene expression analyses, showed that highly susceptible salmon erected a response mainly associated with an increased expression of interleukin-1beta (IL-1beta), interferon-gamma (IFN-gamma), IL-10 and infiltration of CD3-positive cells in the epidermis of infected fins. Less susceptible salmon showed no initial response in fins but 3-6 weeks post-infection a number of other genes (encoding the immune-regulating cytokine IL-10, cell marker MHC II and the pathogen-binding protein serum amyloid A) were found to be up-regulated. No proliferation of epithelial cells was seen in the skin of less susceptible salmon, and IL-10 may play a role in this regard. It can be hypothesized that resistant salmon regulate the parasite population by restricting nutrients (sloughed epithelial cells and associated material) and thereby starve the parasites. In association with this 'scorched-earth strategy', the production of pathogen-binding effector molecules such as serum amyloid A (SAA) (or others still not detected) may contribute to the resistance status of the fish during the later infection phases.

The gill monogene communities of Pimephales promelas (fathead minnow) in 3 distinct sites on converging streams were investigated from 2004 to 2006 in 3 different seasons. Thirty collections of P. promelas were made in southeastern Nebraska along 3 converging tributaries: Elk Creek (40.88534°N, 96.83366°W), West Oak Creek (40.9082°N, 96.81432°W), and Oak Creek (40.91402°N, 96.770583°W), Lancaster County, Nebraska. In all, 103 P. promelas were collected from Elk Creek, 115 from West Oak Creek, and 78 from Oak Creek and examined for gill monogenes. Among the P. promelas collected, 93.5% were infected with up to 3 species of Dactylogyrus, including Dactylogyrus simplex Mizelle, 1937, Dactylogyrus bychowskyi Mizelle, 1937, and Dactylogyrus pectenatus Mayes, 1977. Mean intensities at Elk Creek, West Oak Creek, and Oak Creek were 17.6, 22.8, and 25.1, and prevalences 88, 95, and 97%, respectively. At these 3 sites: (1) P. promelas does not share Dactylogyrus species with Semotilus atromaculatus (Creek chub) or Notropis stramineus (Sand shiner); (2) fish size and sex are not predictive of Dactylogyrus infection; (3) Dactylogyrus spp. vary (not always predictably) in their seasonal occurrence; (4) populations of Dactylogyrus spp. respond to environmental differences among sites; and (5) the community structure of Dactylogyrus spp. (order of abundance) is independent of environment.