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Recent occasional examinations of two species of eels (Anguilliformes: Anguillidae) in Japan, the Japanese eel Anguilla japonica Temminck & Schlegel from central Japan and the giant mottled eel Anguilla marmorata Quoy & Gaimard from southern Japan, respectively, revealed the following four species of gastrointestinal parasitic nematodes: Cucullanus filiformis Yamaguti, 1935 (Cucullanidae) from A. japonica; Paraquimperia japonica n. sp. (Quimperiidae) from A. japonica (type-host) and A. marmorata; Heliconema anguillae Yamaguti, 1935 (Physalopteridae) from A. marmorata (new host record); and Spinitectus anguillae n. sp. (Cystidicolidae) from A. japonica (type-host) and A. marmorata. Specimens of all species are described based on light and scanning electron microscopical examinations. Paraquimperia japonica n. sp. is mainly characterised by the presence of a ventral sucker, spicules 210-231 µm long and by narrow cervical alae, whereas S. anguillae n. sp. by the number (29-36) of cuticular spines in the first ring, the length of the left spicule (351 µm) and the structure (without polar caps, filaments or lateral swellings), and the size of eggs (36-42 × 21-27 µm).

Cucullanus carettae Baylis, 1923 (Nematoda: Cucullanidae) is found worldwide in loggerhead turtles (Caretta caretta). Regarding the Mediterranean, C. carettae has been identified in the Tyrrhenian and the Ionian Sea and a unique description of a Cucullanus sp. specimen in loggerheads from the Adriatic Sea has been reported in the literature so far. In the framework of a bio-monitoring project of the Abruzzo and Molise coasts, a parasitological survey was performed on stranded and by-caught sea turtles, at the Istituto Zooprofilattico of Abruzzo and Molise “G. Caporale.” During necropsy, the gastrointestinal system of 72 stranded loggerhead turtles was analyzed for the presence of endoparasites and fecal samples were collected for coprological examination. Adult C. carettae (n = 123) was found in the upper intestine of one loggerhead turtle, associated with chronic lymphoplasmocytic enteritis. Additionally, five stool samples (6.9%) were positive for Cucullanus sp. eggs. Molecular characterization of adult nematodes was carried out to study phylogenetic relationships among the Cucullanus species. To our knowledge, this is the first morphological and molecular identification of C. carettae in loggerhead turtles from the Adriatic Sea. Additional studies on the distribution of this parasite in the Mediterranean are encouraged.

Structure of the helminth community and analyses of helminth population parameters of Pimelodus blochii collected in the Xapuri River in comparison with those in the Acre River were evaluated. Eight adult helminth species were found parasitizing P. blochii in the Acre River: the nematodes Orientatractis moraveci, Rondonia rondoni, Philometroides acreanensis, Cucullanus (Cucculanus) pinai pinai, Procamallanus (Spirocamallanus) pimelodus, Rhadochona acuminata, and Brasilnema sp., and the trematode Dadaytrema oxycephala. For Xapuri’s fishes, nine helminth species were found: the nematodes O. moraveci, R. rondoni, C. (C.) pinai pinai, Procamallanus (Spirocamallanus) rarus, P. (S.) pimelodus, R. acuminata, Brasilnema sp., and Cystidicolidae gen. sp., and the trematode D. oxycephala. Nematode and Acanthocephala larvae were also reported. Helminth abundance, prevalence, and diversity were influenced by seasonality and locality (river). The helminth parasites from Acre’s fishes formed a subset of the helminth community of the Xapuri’s. The results indicate an influence of the environmental characteristics of the rivers on the helminth community structure and diversity. This is the first study of the parasite community of P. blochii in the Xapuri River. The paretheses of (Spirocamallanus) and (S.) should not be in italics all along the text and tables.

This paper assesses the role of intestinal helminth parasite of Macrobrachium vollenhovenii on host metal accumulation in Lekki lagoon, Lagos, Nigeria. Lead, zinc, copper, chromium and iron concentrations were determined in water, sediment, intestinal parasite, intestine of infected and non-infected prawns. Intestinal nematode parasite Cucullanus sp. was identified. Pb and Cr were not detected in the water and sediment. The sediment had higher concentrations of the metals than the water medium, and exceeded the WHO limits for Zn, Cu and Fe. Cucullanus sp. accumulated Zn 19 times, Cr several thousand times more and Fe 11 times more than the host intestine (wet wt). This parasite could have accumulated these metals from its host, reducing the concentration of these metals in the tissues of the infected prawns compared to non-infected ones. The infected and non-infected prawns accumulated Zn and Fe several times more than the water medium. The parasite influenced metal accumulation in the host tissue and pose ecological risk.

In the present study, new host and locality records of Cucullanus aliyaii Akhtar and Mujib (2012), a cuculanid nematode isolated from the intestine of the rabbitfish, Siganus canaliculatus collected from the Red Sea, coasts of Hurghada city, Egypt during the period from January to September 2017. Fifteen out of 55 (27.3%) of the examined fish were infected. Worms were recorded by naked eyes on the flesh, stomach, intestines, as well as body cavities of the infected fish. Light and scanning electron microscopy revealed that the isolated worms possessed the important criteria characteristic for members of family Cuculanidae: dimensions of oesophagus, spicules, mucron, size of pseudobuccal capsule, eggs, the position of deirids, excretory pore and vulva, numbers and arrangement of caudal papillae, host groups and zoogeographical regions. The recorded parasite was whitish and small-sized, female worms were 9.40±2 (7.4-10.3) x 2.5±0.2 (2.00-2.60) mm while male worms were 6.30±0.02 (6.00-8.30) mm x 1.60±0.02 (1.59-1.73) mm. Oral aperture was dorsoventrally elongate, slit-like, surrounded by distinct collarette, beared one row of small denticles on its inner surface; four submedian cephalic papillae and a pair of prominent lateral amphids present. Oesophagus was of two distinct portions: anterior pseudobuccal capsule measured 0.50±0.02 (0.47-0.053) mm in length, narrowing immediately below nerve ring; and posterior with a club-shaped muscular structure measured 0.45±0.02 (0.41-0.49) mm in length

Summary The metazoan parasites were investigated of two flatfish the common sole, Solea solea (n:140) and the scaldfish, Arnoglossus laterna (n: 22) in the Sinop coast of Black Sea from June 2015 to June 2017. A total of 15 metazoan parasite species belonging to Digenea (6), Cestoda (3), Acanthocephala (1), Nematoda (4) and Isopoda (1) taxonomic groups were identified. Solea solea was found to be infected by Condylocotyla pilodora, Proctoeces maculatus, Opecoelidae gen. sp., Metadena sp., Stephanostomum sp., Progrillotia sp., Capillaria gracilis, Cucullanus campanae, Solearhynchus rhytidotes and Nerocila orbignyi. Arnoglossus laterna was found to be infected by Lecithochirium musculus and Grillotia erinaceus. Scolex pleuronectis, Hysterothylacium aduncum and Dichelyne minutus were determined in both flatfish. Infection prevalence and mean intensity values were re- corded for each parasite species. Infection values for each parasite species in relation to season and fish size were also determined and compared as comparatively. This study is the first one assessing the metazoan parasites both of S. solea and A. laterna collected from the Turkish coast of Black Sea. While Condylocotyle pilodora and Capillaria gracilis are new parasite records for S. solea, Grillotia erinecaus is new parasite record for A. laterna. Moreover, this paper is the first report on occurrence of Opecoelidae gen. sp., Metadena and Stephanostomum genera in S. solea.

Um estudo ictioparasitológico foi conduzido com 166 indivíduos pertencentes às espécies Poecilia reticulata Peters, 1859 (Poeciliidae), Rhamdia quelen (Quoy & Gaimard, 1824) e Hypostomus ancistroides (Ihering, 1911) (Loricariidae) em riachos afluentes do rio Pirapó, localizados na zona urbana e entorno da cidade de Maringá-PR. A pesquisa objetivou o levantamento da comunidade de endoparasitos nos peixes analisados, assim como um aprofundamento no conhecimento da relação parasita/hospedeiro. Dessa forma, foram analisadas possíveis correlações entre o Comprimento Total dos peixes com os níveis de parasitismo (prevalência, abundância). Em função da existência de dimorfismo sexual na espécie P. reticulata, foram investigadas possíveis influências do sexo deste peixe no parasitismo. De forma complementar, também foi analisada a superfície corporal e narina dos peixes na procura por ectoparasitos. Porém, não foram identificados metazoários parasitos na superfície do corpo e narina de nenhuma das espécies analisadas. Apenas 15,06% de prevalência endoparasitária foi observada nos hospedeiros investigados. Uma espécie de pentastomideo, Sebekia oxycephala (Diesing) Sambon, 1922, e um cestóide da ordem Pseudophyllidea foram os endoparasitos encontrados parasitando o peixe P. reticulata, com prevalência de 13,89 e 0,92 %, respectivamente. Rhamdia quelen apresentou prevalência de 39,13 % para o nematóide da espécie Cucullanus (Cucullanus) pinnai Travassos, Artigas e Pereira, 1928. Aespécie H. ancistroides não apresentou parasitos. Não foi observada correlação entre o sexo de P. reticulatacom a prevalência e abundância parasitária de S. oxycephala. Os comprimentos totais dos hospedeiros não se apresentaram correlacionados com as prevalências e abundâncias dos endoparasitos. Desta forma, devido ao fato dos parasitos encontrados serem generalistas, não foi observada vinculação do parasitismo com características/peculiaridades dos hospedeiros (peixes) analisados, como ocorre com parasitos de elevada especificidade.

The common ponyfish Leiognathus equulus is a marine fish species with very high commercial value. Little information is available about its parasitic infections. Based on light and scanning electron microscopy, as well as sequencing and analysis of the partial regions of the ITS-1, 18S rRNA, COX1 genes, were employed for the systematic evaluation of a nematode parasite, which it first isolated from L. equulus in Jeddah Province, Red Sea, Saudi Arabia. Results revealed that this nematode parasite closely resembles the previously described Cucullanus bulbosus. Microscopic examination showed that it distinguished from congeners by the unique structure of hemispherical elevation at pseudobuccal capsule level, the ratio of esophagus/body length, spicules size, presence of pre-cloacal sucker, rod-shaped gubernaculum, and the arrangement of caudal papillae in males. Phylogenetic analyses based on ITS-1, 18S rRNA, and COX1 gene regions were constructed to investigate phylogenetic relationships between this parasite species and other related taxa. Results supported that Cucullanus bulbosus resembles a sister of Cucullanus genypteri, Cucullanus pulcherrimus, Cucullanus bourdini, Cucullanus extraneus, and Cucullanus hainanensis by using different genetic markers. This study provides more information about combining morphological and molecular data to identify Cucullanus species with the first natural occurrence in the common ponyfish inhabited in Saudi Arabia.

Many nematode species parasitizing marine fishes were reported from Japanese waters. However, considering the wealth of fish species in this zoogeographically interesting region and the host specificity of nematodes, the number of hitherto recorded fish nematodes probably represents only a very small part of the potential Japanese fauna of these organisms. Therefore, new data are needed to recognise the species composition of these parasites in this region. Helminthological examinations of some marine fishes from off Japan, carried out in the years 2005–2017, revealed one new and five insufficiently known species of ascaridoid and seuratoid nematodes. These were studied with the use of light and scanning electron microscopy. All six nematode species recorded are described: Anisakidae: Raphidascaris (Ichthyascaris) multipapillata sp. nov. (male and females) from the intestine of Labracoglossa argenteiventris Peters (Kyphosidae) in the Sea of Japan, Raphidascaris (Ichthyascaris) sp. (third-stage larvae) probably from the digestive tract of Seriola dumerili (Risso) and S. rivoliana Valenciennes (both Carangidae) in the western North Pacific Ocean off Ishigaki-jima Island, Okinawa Prefecture, Hysterothylacium simile Li et al., 2013 (males and females) from the stomach of Lateolabrax japonicus (Cuvier) (Lateolabracidae) in the Sea of Japan, Hysterothylacium sp. 1 (female) from the pyloric caeca of Jaydia lineata (Temminck et Schlegel) (Apogonidae) in the Seto Inland Sea, Hysterothylacium sp. 2 (third- and fourth-stage larvae) from the intestine and mesentery of Etelis coruscans Valenciennes (Lutjanidae) and Pseudorhombus pentophthalmus Gunther (Paralichthyidae) in the western North Pacific Ocean off Ishigaki-jima Island, Okinawa Prefecture and the Seto Inland Sea, respectively; and Cucullanidae: Cucullanus sp. (female) from the intestine of Semicossyphus reticulatus (Valenciennes) (Labridae) in the Seto Inland Sea. Raphidascaris (I.) multipapillata sp. n. differs from congeners mainly in the high number (79) of pairs of caudal papillae, spicules 402 µm long and in the structure of the male and female tail tips. Hysterothylacium simile is redescribed, being recorded from off Japan for the first time. In addition to the discovery of the new nematode species R. (I.) multipapillata sp. nov. and a redescription of H. simile providing some new morphological data of this parasite, the findings of all other species represent new host and geographical records. The present study extends the knowledge of the species composition and host–parasite relationships of nematodes parasitizing marine fishes.

Studies about the parasite fauna of marine fish highlights as an important problem for public health with zoonotic parasites or affecting the fish quality. Thus, this study evaluated the parasite fauna of Lutjanus synagris commercialized in the fish market from Braganca-PA. In laboratory, 58 fish were measured, weighted and conducted to parasitological analysis to determine parasitological indexes and relative dominance. Every parasite was fixed and identified until to the lowest taxonomic level. Through the parasitological analysis, it found Cymothoidae, Digenea, Cucullanus sp. and Procamallanus (Spirocamallanus) sp., with total prevalence 67.24%. Digenea showed the highest prevalence and mean intensity values. For nematode, Cucullanus sp. obtained the greater prevalence and relative dominance, while Procamallanus (Spirocamallanus) sp. showed the greater mean intensity and abundance. Cymothoidae showed the lowest prevalence and mean intensity values. As conclusion, the parasite fauna of L. synagris has been noted with low diversity, reporting the nematode occurrence Procamallanus (Spirocamallanus) .

Pseudoplatystoma (Bleeker, 1862) species are of commercial importance in the region of Rondônia, however studies with the species are scarce, so the objective of the research was to carry out a diagnosis of the composition and structure of the parasite communities of Pseudoplatystoma fasciatum (Linnaeus, 1766) and P. tigrinum (Valenciennes, 1840) of the river basin Jamari, Ariquemes - RO, Brazil. During the period from November / 2016 to February / 2018, 50 specimens of P. tigrinum and 51 specimens of P. fasciatum were collected. Of the total sampled fish, 45 specimens of P. tigrinum and 51 specimens P. fasciatum were parasitized by at least one species of parasite presenting a prevalence level of 90% and 100%, respectively. In the parasitic infrapopulations of P. tigrinum, the groups with the highest prevalence rates were nematodes, with larvae being the largest representative of the group, followed by monogenean Vancleaveus ciccinus Kritsky, Thatcher e Boeger, 1986 and for P. fasciatum the parasite helminths that presented the highest prevalence level were the Cestoda groups: Megathylacus sp. Woodland, 1934; Harriscolex sp. Rego, 1987; Monticellia sp. La Rue, 1911; Nominoscolex sp. Woodland, 1934; Nematoda: larvae; Eustrongylides sp. Jägerskiöld, 1909; Cucullanus sp. Müller, 1777; Contracaecum sp. Railliet Henry, 1912 and Monogenea: Vancleaveus ciccinus One species showed a negative correlation between total length and average abundance for P. tigrinum, while P. fasciatum correlation was positive for three species. The comparison of abundance averages by sex for P. tigrinum showed no significant difference between groups, for P. fasciatum a significant difference was observed among the individuals parasitized by Peltidocotyle sp., Monticellia sp., Nominoscolex sp. where females showed higher average abundance in relation to males.

Cucullanus marajoara n. sp. (Cucullanidae) is reported to parasitize Colomesus psittacus (Tetraodontiformes), which is a fish species from the Marajó Archipelago, state of Pará, estuarine region of the Brazilian Amazon. The new species differs from similar species by the presence of a protruding upper lip on the cloacal opening, the distribution of the cloacal papillae: five pre-cloacal papillae pairs and 5 are ventral and located posteriorly to the pre-cloacal sucker and an unpaired papilla is located on the upper cloacal lip and five post-cloacal pairs, and a pair of lateral phasmids located between papillae pairs. Additionally, Cucullanus marajoara n. sp. is compared to other species of this genus described in Brazil, particularly Cucullanus ageneiosus and Cucullanus oswaldocruzi, which both occur in the same zoogeographic region of this study but parasitize fish of a different order (Siluriformes). Cucullanus dodsworthi and Cucullanus brevicaudatus are the only described species parasitizing fish of the order Tetradontiformes in Brazil, and the new species differs from these species by the distribution of the cloacal papillae and the host habitat. The description of Cucullanus marajoara n. sp. adds data to the biodiversity of described parasites that parasitize Tetradontiformes of the estuarine ichthyofauna in the Brazilian Amazon. Resumo Cucullanus marajoara n. sp. (Cucullanidae) é descrita parasitando Colomesus psittacus (Tetraodontiformes) peixe do arquipélago de Marajó, Estado do Pará, região estuarina da Amazônia brasileira. A nova espécie difere de seus congêneres por apresentar lábio superior da abertura cloacal protrudente e na distribuição de papilas cloacais: 5 pares pré-cloacais, e uma papila não pareada no lábio superior da cloaca e 5 pares pós-cloacais, um par de fasmídeos laterais. Além disso, Cucullanus marajoara n. sp. é comparada com outras espécies do gênero descritas no Brasil, em especial Cucullanus ageneiosus e Cucullanus oswaldocruzi, ambos parasitos de peixes da ordem Siluriformes; porém, ocorrendo na mesma região zoogeográfica deste estudo, diferem da ordem do hospedeiro da nova espécie (Tetraodontiformes). Cucullanus dodsworthi e Cucullanus brevicaudatus são as únicas espécies descritas parasitando peixe da ordem Tetradontiformes no Brasil, e a nova espécie difere dessas na distribuição das papilas cloacais e habitat dos hospedeiros. Cucullanus marajoara n. sp. adiciona dados a biodiversidade de parasitos descritos parasitando Tetradontiformes da ictiofauna estuarina da Amazônia brasileira.

The aim of the study was to examine metazoans parasite communities of European eels (Anguilla anguilla) in freshwater (Tonga Lake) and brackish water (El Mellah lagoon) in the northeast of Algeria. Six parasite taxa were collected: one monogenean, Pseudodactylogyrus sp.; two crustaceans, Ergasilus sp. and Argulus foliaceus; two nematodes, Cucullanus sp. and Anguillicola crassus; one cestode, Bothriocephalus claviceps. Th e most prevalent parasite taxa in freshwater were Pseudodactylogyrus sp., A. crassus and Bothriocephalus claviceps; whereas in the brackish water, eels were infected mainly with A. crassus. Th e characteristics of the parasite component community structure revealed low parasite species diversity and high dominance values in eels from the two localities. Both communities were dominated by a single parasite species: Tonga eels by the monogenean Pseudodactylogyrus sp. and El Mellah lagoon eels by the nematode A. crassus, verified by high Berger-Parker dominance values of 0.76 and 0.87 respectively.

We suggest helminthological investigations of cod as a supplement to traditional biological and hydrographical methods for elucidation of ecological changes in the Baltic Sea. It is under discussion if oxygen deficit or seal abundance should explain the present critical situation of Baltic cod. A comparative investigation of endoparasitic helminths in Baltic cod (Gadus morhua), captured in the same marine habitat with an interval of 35 years (1983/2018) recorded 11 species of helminths comprising trematodes (Hemiurus luehei, Podocotyle atomon, Lepidapedon elongatum), nematodes (Contracaecum osculatum, Hysterothylacium aduncum, Capillaria gracilis, Cucullanus cirratus), cestodes (Bothriocephalus sp.) and acanthocephalans (Echinorhynchus gadi, Pomphorhynchus laevis, Corynosoma semerme). Significant prevalence and intensity increases were recorded for third-stage larvae of the nematode C. osculatum (liver location) and larvae of C. semerme (encapsulated in viscera). Both parasite species use grey seal as their final host, indicating the recent expansion of the Baltic seal population. A lower E. gadi intensity and an increased prevalence of L. elongatum of small cod (31–40 cm body length) suggest a lowered intake of amphipods (intermediate host) and elevated ingestion of polychaetes, respectively, but no significant changes were seen for other helminths.

Eighty-three Vermilion snappers (Rhomboplites aurorubens) from the northern Gulf of Mexico and 1 from off Puerto Rico, U.S.A., were examined for parasites. The survey resulted in recovery of 2 species of Monogenea: Euryhaliotrema tubocirrus and Microcotyloides incisa; 6 species of Digenea: Parahemiurus merus, Lecithochirium floridense, Hirudinella sp., Aponurus laguncula, Prosogonotrema bilabiatum, Preptetos trulla; 3 species of Nematoda: Hysterothylacium reliquens, Cucullanus pargi, unidentified Cucullanidae; and 3 species of Copepoda: 1 species in Chondracanthidae, 1 species in Caligidae, and Hatschekia sp. Stomach parasites dominated the assemblage with Pro. bilabiatum exhibiting the greatest prevalence (63.9%) and A. laguncula exhibiting the greatest mean intensity (4.6 parasites/infected host ± 6.4 SD) among parasites. Preptetos trulla and Hy. reliquens occurred at both locations and represented the only parasites found in the fish from Puerto Rico, U.S.A. Rhomboplites aurorubens represents...

We investigated and compared the structure of parasite communities in two sympatric, commercially exploited sharks. We analysed 188 gastrointestinal tracts from a crustacean- feeder Mustelus punctulatus and 157 gastrointestinal tracts from a piscivorous Squalus acanthias. The overall prevalence of helminth parasites was very high (84.0%) for M. punctulatus with nematode Cucullanus micropapillatus as the most abundant species (mean abundance 13.96) and Anisakis spp. larvae as the most prevalent taxa (47.9%). In contrast, only 21.7% of S. acanthias specimens were infected, showing Anisakis spp. larvae as the most prevalent (17.8%) and abundant taxa (mean abundance 0.39). The subsample of Anisakis spp. larvae, isolated from both hosts, was molecularly identified at ITS locus as A. pegreffii. Significant variations among size classes were recorded for M. punctulatus, mainly as a consequence of higher C. micropapillatus loads in larger sharks. Seasonal patterns in prevalence and abundance of C. micropapillatus were recorded for M. punctulatus, with peaks in autumn, while Anisakis spp. larvae prevailed during spring, for both sharks. Sex contributed little to the observed parasite abundances, although female spiny dogfish were more prone to infections than males, and higher helminth diversity was recorded in females in both shark species. The differences in infection parameters between the two shark species likely reflect the variations in foraging strategies and availability of intermediate hosts. Our findings suggest that crustacean feeder M. punctulatus is more susceptible to helminth infections in the Adriatic Sea, which may affect the health status of local shark populations.

Two species of cucullanid nematodes collected from the intestine of marine fishes off New Caledonia were studied with the use of light and scanning electron microscopy (SEM): Dichelyne (Cucullanellus) bodiani n. sp. from Bodianus perditio (Quoy & Gaimard) (Perciformes: Labridae), characterised mainly by the small size of the body (males and gravid females 2.26-3.13 mm and 2.46-3.32 mm long, respectively), the presence of very long spicules (1.53-1.66 mm in length), the remarkably large seminal vesicle and the arrangement of caudal papillae, is the second known species of Dichelyne Jagerskiold, 1902 parasitising fishes of the Labridae and the second nominal species of this genus recorded from fishes in New Caledonian waters. Cucullanus hansoni Olsen, 1952, originally described from Hawaii, is now, after 67 years, again reported from its type-host, Sufflamen fraenatum (Latreille) (Tetraodontiformes: Balistidae), from off New Caledonia. The SEM examination of C. hansoni, used in this species for the first time, revealed some new morphological details, such as the presence of a median precloacal cuticular elevation or the shape of deirids and distal tips of spicules, as well as the exact location of caudal papillae and phasmids in the male. This is the seventh species of Cucullanus Muller, 1777 recorded from fishes off New Caledonia.

The phylogenetic relationships of Cucullanidae were explored using near-complete sequences of the 18S rDNA (rRNA gene). Sequences (1,750-1,760 bp) were obtained from 7 species of Cucullanidae belonging to 3 genera, Cucullanus (2 spp.), Dichelyne (2 spp.), Truttaedacnitis (3 spp.), and 1 species of Quimperiidae ( Paraseuratum sp.). These sequences were aligned with those of 128 other nematode species available in GenBank, including 3 other cucullanids (Dichelyne mexicanus, Cucullanus robustus, and Cucullanus baylisi) and 2 non-cucullanid seuratoids (Paraquimperia africana, and Linstowinema sp.). Bayesian (BPP) and maximum likelihood (ML) analyses of 2 different datasets strongly supported a monophyletic Cucullanidae. Bayesian analysis placed this family as the sister group to a clade containing species of Diplogasterida, Strongylida, Rhabditida, and Tylenchida with very strong support. Neither BPP nor ML analyses recovered a close relationship of Cucullanidae to Ascaridida. None of the 3 non-cucullanid seuratoid species were sister to Cucullanidae, nor did they form a monophyletic group of their own, which questions the monophyly of Seuratoidea and the relationships among species within this superfamily. The 3 genera of cucullanids were also not monophyletic, although morphologically similar species such as the 2 species of Cucullanus from Neotropical catfishes and 2 species of Dichelyne from Nearctic ictalurid catfishes were sister taxa with strong support. The results were ambiguous with respect to the relationship of 2 Truttaedacnitis spp. in Nearctic freshwater fishes but do not support Truttaedacnitis heterodonti, a parasite of heterodontid sharks, as belonging to this genus. The study shows that all aspects of the conventional classification of Seuratoidea and its taxa should be scrutinized by even more extensive sampling across hosts and habitats.

Parasitological research of two landlocked populations of Dolly Varden (Salvelinus malma) dwelling the river–lake system in the Uzon caldera (Kamchatka) was done for the first time. Twelve species of fresh-water parasites were found. Charrs from the Lake Tsentral’noe–Shumnaya River were infected by Eubothrium salvelini, Diphyllobothrium ditremum, D. dendriticum, Crepidostomum farionis, Cr. metoecus, Ichthyocotylurus erraticus, Sterliadochona ephemeridarum, Philonema oncorhynchi, and Cucullanus truttae. Charrs from the Lake Dal’nee were infected by Henneguya zschokkei, Chloromyxum coregoni, Proteocephalus longicollis, and Cucullanus truttae. Based on stomachs content and parasites abundance, it was found that charrs from the Lake Dal’nee feed on plankton, and at length more than 12 cm, switch to cannibalism. In the contrast, charrs from the Lake Tsentral’noe and Shumnaya River primarily feed on benthos and rarely on plankton, and no cannibalistic specimens were found.

Fry of the coho salmon, Oncorhynchus kisutch (Walbaum, 1792), which were caught in the Kronotskaya River, were found to include six species of parasites belonging to four classes: Monogenea (Salmonchus alaskensis), Cestoda (Proteocephalus longicollis), Nematoda (Sterliadochona ephemeridarum, Cucullanus truttae, Philonema oncorhynchi), and Acantocephala (Neoechinorhynchus salmonis). The intensity of the parasitic invasion was not above three specimens per fish.

Twenty species (sixteen adult and four larval) of parasitic nematodes belonging to the Ascaridoidea, Camallanoidea, Cosmocercoidea, Dioctophymatoidea, Habronematoidea, Oxyuroidea, Seuratoidea, and Thelazioidea were collected from freshwater fishes of the Congo River basin in the Democratic Republic of the Congo and the Central African Republic in 2008 and 2012, respectively. Based on light and scanning electron microscopical examination, many species are redescribed in detail. This material also contained four previously unknown species, Labeonema longispiculatum sp. n. from Synodontis acanthomias Boulenger, Gendria longispiculata sp. n. from Schilbe grenfelli (Boulenger), G. sanghaensis sp. n. from Schilbe marmoratus Boulenger, and Cucullanus congolensis sp. n. from Auchenoglanis occidentalis (Valenciennes). The new species L. longispiculatum is mainly characterised by conspicuously long (210-228 µm) spicules, approximately twice as long as those in other congeners, the length (45-48 µm) of the gubernaculum and the host family (Mochokidae), whereas G. longispiculata by very long (1.2 mm) spicules, the shape of the oesophagus and cephalic vesicle, distribution of postanal papillae and the host family (Schilbeidae). Main characteristic features of G. sanghaensis are the presence of a hexagonal oral aperture surrounded by lip-like structures, the posterior portion of the oesophagus moderately expanded, spicules and the gubernaculum 414-438 µm and 54-57 µm long, respectively, deirids located at the level of the posterior end of the oesophagus and the absence of cervical alae. Cucullanus congolensis differs from congeneric species parasitising African freshwater and brackish-water fishes mainly in the absence of a ventral precloacal sucker and lateral preanal papillae, the presence of a large median precloacal papilla-like formation, spicules 480-489 µm long and the location of the excretory pore in the region of the oesophago-intestinal junction. Chabaudus Inglis et Ogden, 1965 is considered a junior synonym of Gendria Baylis, 1930 and, consequently, species listed in the former genus are transferred to the latter as G. alaini (Alfonso-Roque, 1981) comb. n., G. chabaudi (Inglis et Ogden, 1965) comb. n., G. dehradunensis (Rizvi, Bursey et Maity, 2016) comb. n., G. thysi (Puylaert, 1970) comb. n. and G. williamsi (Puylaert, 1970) comb. n. The findings represent many new host and geographical records.

Cucullanus congolensis sp. n. Figs. 22, 23 ZooBank number for species: urn:lsid:zoobank.org:act: 95D554AD-8D31-47B2-9B10-FBF4BB698FA6 Description. Medium-sized nematodes. Body whitish, elongate, with slightly transversely striated cuticle. Lateral alae absent. Cephalic end somewhat asymmetrical in lateral view. Oral aperture dorsoventrally elongate, surrounded by raised narrow membranous ala (collarette) supported by row of ca 70 minute basal teeth (Figs. 22C, 23A–C). Four submedian cephalic papillae and pair of lateral amphids present (Figs. 22C, 23A–C). Oesophagus muscular, expanded at anterior end to form bulbous pseudobuccal capsule (oesophastome); posterior part of oesophagus also expanded, somewhat narrower than oesophastome in lateral view (Fig. 22A,B). Oesophagus opens into intestine through large valve. Nerve ring encircles oesophagus at distance representing 35–42% of oesophageal length. Deirids small, situated approximately at midway between nerve ring and posterior end of oesophagus (Figs. 22A,B,E, 23H). Postdeirids not found. Excretory pore in region of oesophago-intestinal junction (Fig. 22B). Tail of both sexes conical, sharply pointed at tip. Male (2 specimens; holotype; measurements of paratype in parentheses). Length of body 6.7 mm (5.0 mm), maximum width 231 (163); width at level of oesophastome 165 (150), at middle of oesophagus 159 (136). Length of entire oesophagus 775 (775), representing 12% (16%) of whole body length; length of oesophastome 240 (225), its width 150 (111); minimum width of oesophagus 63 (45); maximum width of posterior part of oesophagus 120 (105). Distance of nerve ring from anterior extremity 313 (326), representing 40% (42%) of oesophageal length. Deirids and excretory pore 517 (707) and 748 (775), respectively, from anterior end of body. Posterior end of body curved ventrally. Ventral sucker and ventral precloacal oblique muscle bands absent (Figs. 22G, 23E). Cloacal region not elevated. Large median papilla-like formation present anterior to cloacal opening (Figs. 22F–H, 23D–G). Spicules equal, 480 (489) long, with rounded posterior ends (Fig. 22G), representing 7% (10%) of body length. Gubernaculum well sclerotised, small, rod-like with narrow proximal part in lateral view, 105 (63) long (Fig. 22F,G). Caudal papillae 11 pairs: 6 pairs of preanal papillae (5 subventral and 1 lateral) and 5 pairs of postanal papillae (3 subventral, 1 lateral and 1 dorsolateral); preanal pair of laterals located well anterior to cloacal opening; first postanal pair of subventrals just posterior to cloacal opening, second and third postanal pairs of subventrals in posterior half of tail; postanal pair of laterals (probably representing phasmids) slightly anterior to level of second subventral pair; papillae of dorsolateral postanal pair slightly anterior to level of last subventrals (Figs. 22F–H, 23D–G). Length of tail 216 (156). Female (2 specimens with immature eggs; allotype; measurements of paratype in parentheses). Length of body 6.2 mm (8.4 mm), maximum width 204 (218); width at level of oesophastome 163 (136), at middle of oesophagus 122 (136). Length of entire oesophagus 816 (898), representing 13% (11%) of whole body length; length of oesophastome 245 (192), its width 136 (105); minimum width of oesophagus 109 (45); maximum width of posterior part of oesophagus 120 (99). Distance of nerve ring from anterior extremity 326 (313), representing 40% (35%) of oesophageal length. Deirids and excretory pore 694 (544) and 775 (870), respectively, from anterior end of body. Vulva postequatorial, 3.7 mm (4.6 mm) from anterior extremity, at 60% (55%) of body length; vulval lips not elevated. Vagina directed anteriorly from vulva. Uteri opposed, containing few immature eggs. Length of tail 231 (340); phasmids indistinct (Fig. 22D). Type host: Bubu Auchenoglanis occidentalis (Valenciennes) (Siluriformes: Claroteidae). Site of infection: Intestine (distal part). Type locality: Lower Congo River, left bank near Pioka, 04°54'25''N; 14°23'53''E, and right bank near Bulu, 05°01'30''N; 14°00'25''E, Democratic Republic of the Congo (collected 7 and 11 July 2008). Prevalence and intensity: 2 fish infected/7 fish examined; 1 and 4 nematodes. Deposition of type specimens: IPCAS N-1134 (holotype mounted on SEM stub, allotype and 2 paratypes in vials). Etymology: The species name congolensis relates to the Congo River, where this parasite was found. Remarks. The following six nominal species of Cucullanu s have been, mostly inadequately, described from freshwater and brackish-water fishes in Africa: C. barbi Baylis, 1923, C. baylisi Campana-Rouget, 1961, C. clarotis Baylis, 1923, C. djilorensis Ndew, Diouf, Bâ et Morand, 2014, C. egyptae Abdel-Ghaffar, Bashtar, Abdel-Gaber, Morsy, Mehlhorn, Al Quraishy et Mohammed, 2014 and C. mormyri Moravec et Scholz, 2017 (see Baylis 1923a, Campana-Rouget 1961, Abdel-Ghaffar et al. 2014, Ndew et al. 2014, Moravec and Scholz 2017). By the absence of a ventral precloacal sucker, the new species can be easily distinguished from C. egyptae, C. barbi and C. djilorensis, parasites of anguilliform, cypriniform and mugilliform fishes, respectively, in which the sucker is present. Cucullanus mormyri, a parasite of osteoglossiform fishes, differs from C. congolensis sp. n. mainly in the location of the excretory pore situated at a long distance posterior to the end of the oesophagus (vs in the region of the oesophago-intestinal junction) and the absence of lateral preanal papillae. Both C. baylisi and C. clarotis are parasites of siluriforms (catfishes) as the new species. However, C. baylisi, a specific parasite of Mochokidae (Synodontis spp.), possesses no lateral preanal papillae (see Moravec and Scholz 2017), in contrast to C. congolensis, in which large lateral preanal papillae are present (Figs. 22F–H, 23D–G). The presence of large lateral preanal papillae, as in C. congolensis, was described and illustrated for C. clarotis (see Baylis 1923a); moreover, both species are parasites of Claroteidae. Baylis (1923a) reported female specimens of C. clarotis also from Synodontis schall (Mochokidae), but these were subsequently assigned to C. baylisi based on a re-examination of Baylis’ original specimens by Campana-Rouget (1961). However, in contrast to the original description of C. clarotis, specimens of the present material possess a large median precloacal papilla-like formation (vs such structure not reported for C. clarotis) and they also differ in the smaller body length of males (5.0– 6.7 mm vs 7.0–10.0 mm), shorter spicules (480–489 µm vs 800 µm) and the oesophagus (775 µm vs 850–1,100 µm), location of the excretory pore in region of the oesophago-intestinal junction (vs approximately at mid-length of oesophagus), the genus and species of fish hosts (Aucheniglanis occidentalis vs Clarotes laticeps [Rüppel]) and different biogeographic affinity (Congolean ichthyological province vs Nilo-Sudanian ichthyological province). Although it cannot be excluded that future studies of C. clarotis may show its conspecificity with C. congolensis, for the time being we consider it more reasonable to deal with these forms as two separate species.

Based on light and scanning electron microscopical studies, two new species of parasitic nematodes are described from marine perciform fishes off New Caledonia: Cucullanus epinepheli sp. n. (Cucullanidae) from the intestine of the brownspotted grouper Epinephelus chlorostigma (Valenciennes) (Serranidae) and Procamallanus (Spirocamallanus) sinespinis sp. n. from the intestine of the silver grunt Pomadasys argenteus (Forsskål) (Haemulidae). Cucullanus epinepheli sp. n. differs from its congeners mainly in possessing a unique structure of the anterior, elevated cloacal lip with a large posterior outgrowth covering the cloacal aperture and in the presence of cervical alae and two small preanal papillae on the median dome-shaped precloacal elevation. This is the second known nominal species of this genus parasitising fishes of the family Serranidae and the second representative of Cucullanus Müller, 1777 recorded from fishes in New Caledonian waters. Procamallanus (Spirocamallanus) sinespinis sp. n. is mainly characterised by 10-12 spiral ridges in the buccal capsule, the presence of wide caudal alae, three pairs of pedunculate preanal papillae, two unequally long spicules (465-525 µm and 218-231 µm) and by the tail tip with a knob-like structure in the male, and the broad, rounded tail with a terminal digit-like protrusion without cuticular spikes in the female. This is the fifth nominal species of the subgenus Spirocamallanus Olsen, 1952 reported from fishes in New Caledonian waters.

Fourteen species (twelve adult and two larval) of nematodes belonging to the Ascaridoidea, Camallanoidea, Cosmocercoidea, Habronematoidea, Oxyuroidea, Seuratoidea and Trichinelloidea were collected from fishes in the Sudan (River Nile and Atbara Dam Lake), whereas only four species (one adult and three larval) of the Ascaridoidea, Camallanoidea, Dioctophymatoidea and Trichinelloideafrom fishes in Ethiopia (Lake Tana). The Sudanese material also contained two previously unknown species, Cucullanus mormyri sp. n. from Mormyrus caschive Linnaeus (type host), Mormyrus sp. and Marcusenius cyprinoides (Linnaeus) (all Mormyridae), and Procamallanus (Spirocamallanus) pseudospiralis sp. n. from Synodontis schall (Bloch et Schneider) (type host), S. frontosus Vaillant and S. nigrita Valenciennes (all Mochokidae), which are described based on light and scanning electron microscopical studies. Cucullanus baylisi Campana-Rouget, 1961, a little-known parasite of Synodontis spp., is redescribed in detail. A key to Procamallanus (Spirocamallanus) spp. from African inland fishes is provided. Falcaustra guiersi Vassiliadès, 1973 is considered a junior synonym of F. hexapapillata (Khalil, 1962). The findings represent several new host and geographical records. Cucullanus baylisi Lakshmi, 2000 (= a homonym to C. baylisi Campana-Rouget, 1961) is re-named as C. dubius nom. n. and is considered a species inquirenda.

Nematoda parasites of five greenling species from the Far-Eastern Seas ( Pleurogrammus azonus , P . monopterygius , Hexagrammos octogrammus , H . lagocephalus , H . stelleri ) are investigated. The family Hexagrammidae is endemic for the North Pacific. In total, 10 species of nematodes are found: Anisakis simplex l., Pseudoterranova decipiens l., Hysterothylacium aduncum , Contracaecum osculatum l., Ascarophis filiformis , A. curvicauda , A. pacifica , Cucullanellus minutus , Cucullanus heterochrous , and Paracapillaria helenae , all of them have wide geographical and hosts distribution. Anisakis simplex l. and Pseudoterranova decipiens l. are the most common for all investigated host species. The highest species diversity of nematodes (7 species) is registered for arabesque greenling P. azonus , particularly its females; Contracaecum osculatum l. and Cucullanus heterochrous are found for the first time for this host in the Japan Sea. The parasites are dispersed irregularly in muscles of all parts of fish body. Large-sized (i.e. elder) fish is higher infected by larvae of P. decipiens .

Cucullanus brevicaudatus n. sp. (Cucullanidae) is described from the intestine of Balistes capriscus Gmelin (Balistidae) off Rio de Janeiro, Brazil. The new species can be differentiated from its congeners in the small body length, the shape of the gubernaculum, the particular size and morphology of the tail in both males and females, the arrangement of the caudal papillae, the narrow oesophageal base, and the eggs with rugged shells. In addition, the combination of some features, i.e. number of caudal papillae, spicule length, oesophagus/body length ratio, host family and geographical distribution, can help to easily distinguish the new species from other cucullanids. Considering these features, C. brevicaudatus differs from the species assigned to Dichelyne Törnquist, 1931 which exhibit morphological proximity with Cucullanus Müller, 1777. Regarding the life-cycle of cucullanid nematodes, available evidence suggests that some species are primarily heteroxenous using invertebrates (i.e. crustaceans, polychaetes) as intermediate hosts, but in other a histotrophic phase in the definitive host replaces the intermediate host.

OBJECTIVE The aim of this study is to determine the parasitic nematodes of fish near Gokceada, their host and infection values. METHODS The fish caught by various fishing methods were transported to the laboratory. The fishes were dissected and studied for nematoda. At first, the nematodes were investigated live and some of these nematodes were fixed. Later these nematodes were cleared in lacthofenol and identified. RESULTS In this study, a total of 887 fish samples belonging to different 50 fish species, were investigated and 7 species of nematoda were found, (Anisakis simplex, Contracaecum fabri, Contracaecum aduncum, Cucullanus micropapillatus, Cucullanus hians, Ascarophis sp,. Echinocephalus spinosissimus). CONCLUSION Anisakis simplex and Contracaecum fabri, found in different 11 fish species, were the dominant species for this region.

Cucullanus elongatus Smedley, 1933 Synonym: Cucullanus smedleyi Campana-Rouget, 1957 Description (after Berland 1983). With characteristics of the genus. Body exceptionally long for a cucullanid, up to over 30 in males, and 40 in females. Head rounded, slit-like mouth opening shifted slightly to dorsal side. Double club-shaped oesophagus. Narrow isthmus between anterior and posterior swollen portions of oesophagus surrounded by nerve ring. Excretory pore between nerve ring and intestine. Cuticle thin in anterior body, increasing to about 0.007 at mid-body, and to about 0.010 near anus. Cuticular striations relatively fine throughout. Pair of lateral deirids at about level of mid-oesophagus, and pair of lateral papillae near mid-body (Fig. 93 A). Mouth opening oval, surrounded by collarette, provided on inner face with about 60 short triangular teeth on each side. Two pairs of large cephalic papillae and one pair lateral amphids external to collarette. Raised, smooth, tubular peribuccal rim lying internal to collarette. Posterior to peribuccal rim on each side a large, bilobed, rounded structure (“peribuccal tooth”) projects into pseudobuccal capsule. Cuticular lining of oesophagus and pseudobuccal capsule complex, with cuticular structures extending into surrounding muscles. Tail simple and conical, tapering evenly to a point. Males: 25.54–30.90 long, tapering posteriorly but widening at pre-cloacal sucker; maximum width 0.33–0.40. Oesophagus 1.96–2.32 long. Nerve ring 0.53–0.60, deirids 1.18–1.44 and excretory pore 1.59–1.79 from anterior end. Small spine on post-cloacal wall. Testis single, in anterior body, a loop extends forward to some distance posterior to oesophagus. Left spicule 1.19–1.45, and right spicule 1.19–1.52 long. Gubernaculum 0.064–0.101 long. Proximal cavity or sac ventral to gubernacular limbs, Y-shaped in ventral view. Ten pairs caudal papillae: five pairs pre-cloacal, five pairs post-cloacal. One pair small phasmids (Fig. 93 B). Females: 38.41–43.25 long; maximum width 0.47–0.54. Oesophagus 2.21–2.51 long. Nerve ring 0.60–0.63, deirids 1.29–1.48, excretory pore 1.64–2.05 and vulva 21.38–24.74 from anterior end. Phasmids at about midlength of long tapering tail (Fig. 93 C). Eggs 0.082–0.099 x 0.040–0.047. Site: intestinal lumen Hosts: Ophiodon elongatus (1, 2, 5); Sebastes caurinus (3, 4); Sebastes maliger (4); Sebastes nebulosus (6); Sebastes ruberrimus (4) Distribution: Pacific Records: 1. Smedley 1933; 2. Margolis 1952b; 3. Arai 1969; 4. Sekerak & Arai 1977; 5. Berland 1983; 6. Holmes 1990, Published as part of Arai, Hisao P. & Smith, John W., 2016, Guide to the Parasites of Fishes of Canada Part V: Nematoda, pp. 1-274 in Zootaxa 4185 (1) on pages 160-163, DOI: 10.11646/zootaxa.4185.1.1, http://zenodo.org/record/165530, {"references":["Smedley, E. M. (1933) Nematode parasites from Canadian marine and freshwater fishes. Contributions to Canadian Biology and Fisheries, 8, 169 - 179. http: // dx. doi. org / 10.1139 / f 33 - 014","Berland, B. (1983) Redescription of Cucullanus elongatus Smedley, 1933 (Nematoda: Seuratoidea) from the lingcod Ophiodon elongatus Girard, 1854 from the Pacific coast of Canada. Canadian Journal of Zoology, 61, 385 - 395. http: // dx. doi. org / 10.1139 / z 83 - 051","Margolis, L. (1952 b) Studies on the parasites and diseases of marine and anadromous fish from the Canadian Pacific coast. Ph. D. Dissertation, Institute of Parasitology, McGill University, Montreal, Quebec.","Arai, H. P. (1969) Preliminary report on the parasites of certain marine fishes of British Columbia. Journal of the Fisheries Research Board of Canada, 26, 2319 - 2337. http: // dx. doi. org / 10.1139 / f 69 - 226","Sekerak, A. D. & Arai, H. P. (1977) Some metazoan parasites of rockfishes of the genus Sebastes from the northeastern Pacific Ocean. Syesis, 10, 139 - 144.","Holmes, J. C. (1990) Helminth communities in marine fishes. In: Esch, G., Bush, A. O. & Aho, J. (Eds.), Parasite Communities: Patterns and Processes. Chapman & Hall, New York, pp. 101 - 130. http: // dx. doi. org / 10.1007 / 978 - 94 - 009 - 0837 - 6 _ 5"]}

Cucullanus heterochrous Rudolphi, 1802 Description (after Berland 1970). With characteristics of the genus. Body fairly stout and of even breadth, greatest width just behind oesophagus. Head straight or slightly bent dorsally, and only slightly swollen. Cuticle transversely striated throughout, 0.003–0.007 thick. Mouth a dorso-ventral slit. Collarette surrounding the mouth well developed, the inner face with about 50 teeth on either side. Characteristic two pairs large papillae and one pair amphids on head. Internal circle of six relatively large papillae. Dorsal half of pseudobuccal capsule wide. Peribuccal rim lies well within mouth opening. Oesophagus relatively short, straight at nerve ring level but slightly dilated just behind it (Fig. 94 A). Males: 5.33–7.55 long; maximum width 0.17–0.22. Oesophagus 0.77–0.94 long. Nerve ring 0.31–0.38, deirids 0.69–0.75 and excretory pore 0.91–1.08 from anterior end. Pre-cloacal sucker present. Left spicule 0.78–1.08 long, right spicule 0.71–0.97 long; one spicule, usually the left one, has a screw-like tip, whilst the other is usually straight and more blunt. Both spicules carry broad alae. Gubernaculum 0.046–0.059 long. Pointed tail narrows abruptly behind cloaca. In addition to the usual 11 pairs of caudal papillae there is one large median papilla behind the cloaca (Fig. 94 B). Females: 7.50–10.78 long; maximum width 0.21–0.29. Oesophagus 0.93–1.03 long. Nerve ring 0.37–0.42, deirids 0.82–0.96, excretory pore 1.11–1.19 and vulva 4.56–6.50 from anterior end. Protrusion (“post-cloacal lip”) behind anus (Fig. 94 C). Eggs 0.072–0.091 x 0.042–0.049. Site: alimentary tract Hosts: Hippoglossus stenolepis (2, 3); Limanda ferrugineus (1); Pseudopleuronectes americanus (1) Distribution: Atlantic, Pacific Records: 1. Ronald 1963 (AT); 2. Blaycock 1996 (PA); 3. Blaycock et al. 1998a (PA), Published as part of Arai, Hisao P. & Smith, John W., 2016, Guide to the Parasites of Fishes of Canada Part V: Nematoda, pp. 1-274 in Zootaxa 4185 (1) on page 163, DOI: 10.11646/zootaxa.4185.1.1, http://zenodo.org/record/165530, {"references":["Berland, B. (1970) On the morphology of the head in four species of the Cucullanidae (Nematoda). Sarsia, 43, 15 - 64. http: // dx. doi. org / 10.1080 / 00364827.1970.10411168","Ronald, K. (1963) The metazoan parasites of the Heterosomata of the Gulf of St. Lawrence. VII. Nematoda and Acanthocephala. Canadian Journal of Zoology, 41, 15 - 21. http: // dx. doi. org / 10.1139 / z 63 - 002","Blaycock, R. B. (1996) The parasites of Pacific halibut, Hippoglossus stenolepis, in the northeastern Pacific: ecological patterns in time and space. Ph. D. Dissertation. Department of Biological Sciences, University of Alberta, Edmonton, Alberta, 156 pp.","Blaycock, R. B., Holmes, J. C. & Margolis, L. (1998 a) The parasites of Pacific halibut (Hippoglossus stenolepis) in the eastern North Pacific: host-level influences. Canadian Journal of Zoology, 76, 536 - 547. http: // dx. doi. org / 10.1139 / z 97 - 214"]}

Cucullanus cirratus Müller, 1777 Description (after Berland 1970). With characteristics of the genus. Head slightly swollen and bent dorsad, with characteristic two pairs cephalic papillae and one pair amphids. Mouth bordered externally by collarette, bearing on its inner face many (60 to 70) small teeth on each side. Body widest just behind oesophagus. Excretory pore about midway between nerve ring and oesophago-intestinal junction. Deirids about midway between excretory pore and nerve ring (Fig. 92 A). Cuticle with fine striations throughout body. Males: 10.4–14.7 long; maximum width 0.26–0.32. Oesophagus 1.33–1.62 long. Nerve ring 0.474–0.586, deirids 0.744–0.944 and excretory pore 0.960–1.157 from anterior end. Anus to tail tip 0.218–0.296. Cuticle 0.006–0.007 thick. Right spicule 0.915–0.978 long, left one 0.914–1.02 long. Y-shaped gubernaculum 0.160–0.178 long. Pre-cloacal sucker without cuticular rim present. Eleven pairs caudal papillae (Fig. 92 B). Females: 13.1–20.8 long; maximum width 0.29–0.44. Oesophagus 1.47–1.95 long. Nerve ring 0.525–0.653, deirids 0.82–1.08, excretory pore 1.02–1.34 and vulva 7.50–11.72 from anterior end. Anus to tail tip 0.460–0.514. Cuticle 0.005–0.007 thick. Anterior end to vulva 7.50–11.72 (Fig. 92 C). Eggs 0.075–0.098 x 0.041–0.052. Sites: intestinal lumen, stomach Hosts: Gadus morhua (2, 4); Hippoglossus hippoglossus (7); Melanogrammus aeglefinus (1, 3); Pollachius virens (5); Urophycis tenuis (6) Distribution: Atlantic Records: 1. Kuitunen-Ekbaum 1937b; 2. Gaevskaya & Umnova 1977; 3. Scott 1981; 4. Appy & Burt 1982; 5. Scott 1985; 6. Scott 1987; 7. Scott & Bray 1989, Published as part of Arai, Hisao P. & Smith, John W., 2016, Guide to the Parasites of Fishes of Canada Part V: Nematoda, pp. 1-274 in Zootaxa 4185 (1) on page 160, DOI: 10.11646/zootaxa.4185.1.1, http://zenodo.org/record/165530, {"references":["Berland, B. (1970) On the morphology of the head in four species of the Cucullanidae (Nematoda). Sarsia, 43, 15 - 64. http: // dx. doi. org / 10.1080 / 00364827.1970.10411168","Kuitunen-Ekbaum, E. (1937 b) Intestinal parasites of haddock in Canadian waters. Fisheries Research Board of Canada Manuscript Report (Biology), No. 303, 16 pp.","Gaevskaya, A. V. & Umnova, B. A. (1977) [On the parasite fauna of the principal commercial fishes of the northwest Atlantic.] Biologiya Morya (Vladivostok), 4, 40 - 48. [In Russian]","Scott, J. S. (1981) Alimentary tract parasites of haddock (Melanogrammus aeglefinus L.) on the Scotian Shelf. Canadian Journal of Zoology, 59, 2244 - 2252. http: // dx. doi. org / 10.1139 / z 81 - 304","Appy, R. G. & Burt, M. D. B. (1982) Metazoan parasites of cod, Gadus morhua L., in Canadian Atlantic waters. Canadian Journal of Zoology, 60, 1573 - 1579. http: // dx. doi. org / 10.1139 / z 82 - 207","Scott, J. S. (1985) Occurrence of alimentary tract parasites of pollock (Pollachius virens L.) on the Scotian Shelf. Canadian Journal of Zoology, 63, 1695 - 1698. http: // dx. doi. org / 10.1139 / z 85 - 252","Scott, J. S. (1987) Helminth parasites of the alimentary tracts of hakes (Merluccius, Urophycis, Phycis: Teleostei) of the Scotian Shelf. Canadian Journal of Zoology, 6, 304 - 311. http: // dx. doi. org / 10.1139 / z 87 - 047","Scott, J. S. & Bray, S. A. (1989) Helminths of the alimentary tract of Atlantic halibut (Hippoglossus hippoglossus L.) and Greenland halibut (Reinhardtius hippoglossoides (Walbaum )) on the Scotian Shelf. Canadian Journal of Zoology, 67, 1467 - 1481. http: // dx. doi. org / 10.1139 / z 89 - 209"]}