Two new species of Contracaecum Railliet & Henry, 1912 (Nematoda: Anisakidae), C. fagerholmi n. sp. and C. rudolphii F from the brown pelican Pelecanus occidentalis in the northern Gulf of Mexico.

DNA sequencing of the nuclear ribosomal DNA internal transcribed spacers (ITS) and mitochondrial rrnS and cox2 genes, and analysis of polymorphisms in restriction profiles in the ITS and rrnS, were used to characterise anisakid nematodes belonging to Contracaecum Railliet & Henry, 1912 infecting the brown pelican Pelecanus occidentalis (L.) in Galveston Bay, Texas and Sarasota Bay, Florida. Molecular data led to the detection of two new species: Contracaecum fagerholmi n. sp., which was also supported by clear morphological evidence, and Contracaecum rudolphii F, a new cryptic species within the Contracaecum rudolphii Hartwich, 1964 complex. Bayesian phylogenetic analysis demonstrated that C. fagerholmi and C. rudolphii F form two well-separated clusters, with C. fagerholmi being closely related to Contracaecum bioccai Mattiucci et al., 2008 and C. rudolphii F being included in the C. rudolphii complex. C. fagerholmi can be readily differentiated morphologically from all of its congeners, other than C. microcephalum (Rudolphii 1809) and the five currently recognised members of the C. rudolphii complex (C. rudolphii A, B, C, D and E). C. fagerholmi differs from C. microcephalum in the length of the spicules and the shape of the distal tip of the spicules, and from C. rudolphii (sensu lato) in the shape and size of the ventro-lateral and dorsal lips and by having interlabia which are not distally bifurcate. Further studies are needed to determine which morphological characteristics can be used to distinguish the cryptic species of the C. rudolphii complex in order to assign them with formal names. The recovery of a third species, C. bioccai, from the brown pelican confirms its occurrence in this host and extends its known geographical distribution.

Two new members in the Contracaecum osculatum complex (Nematoda, Ascaridoidea) from the Antarctic.

The genetic structure of adults and larvae of Contracaecum osculatum (sensu lato) from the Antarctic is analyzed on the basis of 24 enzyme loci. Significant deviations of genotype frequencies from the Hardy-Weinberg equilibrium were found, even in samples recovered from the same host. These data indicate that two distinct, reproductively isolated species coexist in C. osculatum (sensu lato) samples from the Antarctic. They were provisionally designated C. osculatum D and E, as they do not correspond to any of the three species previously detected in this complex from the Atlantic Arctic Boreal region (C. osculatum A, B and C). An allozyme diagnostic key for the identification of the five members of the C. osculatum complex, at the larval and adult stage and in both sexes, is given. Species D and E were found to be genetically quite variable: average P99 = 84.3, A = 3.3 and He = 0.23. Both showed high values of intraspecific gene flow: Nm = 4.6 and 6.1 respectively; similar values were found for the Arctic-Boreal C. osculatum A, B and C. The most related members of the complex are the Antarctic species E and the Arctic-Boreal species A (DNei = 0.21), while the most differentiated ones are the Arctic-Boreal species B and C (DNei = 0.76). The evolutionary divergence of C. osculatum C started more than 3 million years ago, in a Pliocene refugium (Baltic Sea). As to the other C. osculatum species, their evolutionary divergence took place during Pleistocene, when this complex achieved a bipolar distribution. This process involved two distinct colonizations of the marine Antarctic region by ancestors of the northern hemisphere, about 1.5 and 1 million years ago, giving origin to C. osculatum D and E respectively.

Genetic evidence for three species within Pseudoterranova decipiens (Nematoda, Ascaridida, Ascaridoidea) in the North Atlantic and Norwegian and Barents Seas.

Genetic variation of 1017 specimens of codworm, Pseudoterranova decipiens, collected from fish and seals at 23 sampling locations in the North Atlantic and Norwegian and Barents Seas, was analysed on the basis of 16 enzyme loci. Three reproductively isolated species, provisionally designated P. decipiens A, B and C, were detected, showing distinct alleles at the following loci: Mdh-1, 6Pgdh, Np, Pgm, Est-2 (between species A and B); Mdh-3, 6Pgdh, Np, Sod-1, Adk, Pgm, Est-2, Mpi (between A and C); Mdh-1, Mdh-3, Sod-1, Adk, Pgm, Est-2, Mpi (between B and C). One F1 hybrid was observed between P. decipiens A and B, but this apparently does not lead to any gene exchange between the two species, which do not show any evidence of introgression. No hybrids or introgressed individuals were observed between P. decipiens C and either A or B. Genetic distances among conspecific populations were low (average Nei's D 0.001-0.005), even though they were collected thousands of kilometres apart, indicating high levels of gene flow within each of the three species. The values of Nei's index D were 0.44 between P. decipiens A and B, 0.57 between B and C, and 0.79 between A and C. Estimated evolutionary divergence times, using Nei's formula, range from 2 to 4 million years. Differences between P. decipiens A, B and C were also found with respect to genetic variability, morphology, geographical distribution and hosts. Mean heterozygosity values of 0.08, 0.05 and 0.02 were obtained for P. decipiens A, B and C, respectively. Preliminary morphological examination of adult males, previously identified by multilocus electrophoresis, revealed differences in the relative size and pattern of caudal papillae. P. decipiens B is widespread in the study area, whereas P. decipiens A was found only in the North-East Atlantic and Norwegian Sea. In this area P. decipiens A is most common in the grey seal, Halichoerus grypus, while the common seal, Phoca vitulina, is the main host for P. decipiens B. In Canadian Atlantic waters, where P. decipiens A is apparently absent, P. decipiens B infects both grey and common seals; a few specimens were also found in the hooded seal, Cystophora cristata. The only definitive host so far identified for P. decipiens C is the bearded seal, Erignathus barbatus; P. decipiens C appears to be widespread, occurring in both the North-West Atlantic and Barents Sea.

Genetic divergence and reproductive isolation between Anisakis brevispiculata and Anisakis physeteris (Nematoda: Anisakidae)s.

In order to assess the taxonomic status of Anisakis brevispiculata Dollfus, 1966 population samples of this taxon from central and south-eastern Atlantic ocean were compared at 22 enzymatic loci with samples belonging to Anisakis physeteris Baylis, 1923 from the Mediterranean sea and central-eastern Atlantic ocean. Very low interpopulational genetic divergence was observed both within A. brevispiculata (average D(Nei) = 0.008) and within A. physeteris (D(Nei) = 0.009) despite the geographic distance among the samples, indicating high levels of gene flow in both taxa. On the other hand, the average genetic distance between A. brevispiculata and A. physeteris was found to be D(Nei) = 0.80, a value generally observed between well differentiated congeneric species. The reproductive isolation between A. brevispiculata and A. physeteris is indicated by the following observations: (1) no F(1) hybrids or recombinant genotypes were until now observed; and (2) the two Anisakis species do not seem to share their definitive hosts. The main definitive host of A. brevispiculata is the pygmy sperm whale (Kogia breviceps), while for A. physeteris it is the sperm whale (Physeter catodon). Only adult males differ slightly in spicule length, while females and larval stages are not differentiated morphologically. Both A. brevispiculata and A.physeteris show a type II larva. The correct recognition of A. brevispiculata from A. physeteris and from other Anisakis species studied, in either sexes and at any life stage, is made easy by allozyme markers (e.g. Icdh, Gapdh, Sod-1, Np, Aat-2, Adk-2, fEst-2, PepB, PepC-2, Mpi). Diagnostic keys, which can be used for routine identification in the field of these Anisakis worms, based on genetic markers, are given.

Three sibling species within Contracaecum osculatum (Nematoda, Ascaridida, Ascaridoidea) from the Atlantic Arctic-Boreal region: reproductive isolation and host preferences.

Genetic variation within and between population samples from 22 locations of the Atlantic Arctic-Boreal region, including 1657 specimens morphologically assigned to Contracaecum osculatum, was electrophoretically analysed at 17 loci. Highly significant deviations from the Hardy-Weinberg equilibrium were found at various loci in several samples, owing to the existence of three distinct gene pools within C. osculatum (sensu lato) from the study area. These gene pools correspond to three biological species (provisionally designated A, B and C), characterized by distinct genotypes at several diagnostic loci. Reproductive isolation between C.osculatum A, B and C is confirmed by the lack of F1, recombinant, or backcross genotypes in sympatric areas, despite the occurrence of multiple infections. Mean heterozygosity per locus is on average 0.11 in species A, 0.10 in B and 0.07 in C. High levels of gene flow were found within each of the three species, the values of Nm (number of migrant individuals) ranging from 3.41 (C. osculatum C) to 5.77 (C. osculatum A). Average Nei's genetic distance is 0.46 between A and B, 0.50 between A and C and 0.77 between B and C. From these values, times of evolutionary divergence from 2 to 4 million years can be estimated. Genetic relationships among populations and species of the C. osculatum complex are illustrated by principal component analysis. The role of both geographical isolation and host preferences in the speciation of C. osculatum (sensu lato) is discussed. A morphological distinction of the three species has not yet been possible (sibling species). However, there is evidence that the name C. osculatum (sensu stricto) should be used for species C, which shows a geographical distribution and definitive host corresponding to the neotype of C. osculatum (sensu stricto). Finally, a comparison is made between the members of the C. osculatum complex from the Atlantic Arctic-Boreal region and those of the Pseudoterranova decipiens complex from the same area, as to: (i) times of evolutionary divergence, (ii) geographical distribution, and (iii) host preferences.

Genetic markers in ribosomal DNA for the identification of members of the genus Anisakis (Nematoda: ascaridoidea) defined by polymerase-chain-reaction-based restriction fragment length polymorphism.

Polymerase-chain-reaction-based restriction fragment length polymorphism analysis was performed to establish genetic markers in rDNA, for the identification of the three sibling species of the Anisakis simplex complex and morphologically differentiated Anisakis species, i.e. Anisakis physeteris, Anisakis schupakovi, Anisakis typica and Anisakis ziphidarum. Different restriction patterns were found between A. simplex sensu stricto and Anisakis pegreffii with two of the restriction endonucleases used (HinfI and TaqI), between A. simplex sensu stricto and A. simplex C with one endonuclease (HhaI), and between A. simplex C and Aniskis pegreffii with three endonucleases (HhaI, HinfI and TaqI), while no variation in patterns was detected among individuals within each species. The species A. physeteris, A. schupakovi, A. typica and A. ziphidarum were found to be different from each other and different from the three sibling species of the A. simplex complex by distinct fragments using 10-12 of the endonucleases tested. The polymorphisms obtained by restriction fragment length polymorphisms have provided a new set of genetic markers for the accurate identification of sibling species and morphospecies.

Occurrence of recombinant genotypes of Anisakis simplex s.s. and Anisakis pegreffii (Nematoda: Anisakidae) in an area of sympatry.

The anisakid nematode populations collected from fish and stranded cetaceans along from Iberian Peninsula waters were morphologically identified as corresponding to the Anisakis simplex complex. In order to realise their molecular identification and to analyse the extent of genetic variation, the entire ITS (ITS1, 5.8S rDNA gene and ITS2) and the mitochondrial small subunit of rRNA were pcr-amplified and sequenced. Digestions of the amplified its region with HinfI and HhaI allowed the identification of three different genotypes, belonging to A. simplex s.s., A. pegreffii and a yet not described recombinant genotype. The ITS sequences of the recombinant genotypes showed the presence of heterozygotes C/T at position 240 and 256 of the aligned sequence. Otherwise, the analysis of mtDNA sequences showed the existence of a different parental origin for recombinant genotypes. In order to check if they can be the products of a polymorphism normally occurring both in A. pegreffii and in A. simplex s.s., and/or the existence of an incomplete concerted evolution, three samples were also collected as controls in isolated geographic areas, where sympatric coexistence between A. simplex s.s. and A. pegreffii does not occur. The results supports the hypothesis that the recombinant individuals may be a product of interspecific hybridisation, and describe the Iberian Peninsula waters as a hybrid zone for the two sibling species.

Genetic and ecological data on the Anisakis simplex complex, with evidence for a new species (Nematoda, Ascaridoidea, Anisakidae).

Isozyme analysis at 24 loci was carried out on anisakid nematodes of the Anisakis simplex complex, recovered from various intermediate/paratenic (squid, fish) and definitive (marine mammals) hosts from various parts of the world. A number of samples were found to belong to A. simplex sensu stricto and Anisakis pegreffii, widely extending the geographic ranges and the number of hosts of these 2 species. In addition, a new distinct gene pool was detected, showing different alleles with respect to A. simplex s. str and A. pegreffii at 5 diagnostic loci (99% level). Samples with this gene pool were assigned to a new species, provisionally labeled A. simplex C. Reproductive isolation between A. simplex C and the other 2 Anisakis species was directly assessed by the lack of hybrid and recombinant genotypes in mixed samples from sympatric areas, i.e., Pacific Canada for A. simplex C+A. simplex s. str., South Africa and New Zealand for A. simplex C+A. pegreffii, even when such samples were recovered from the same individual host. Similar levels of genetic divergence were observed among the three species (DNei from 0.36 to 0.45). At the intraspecific level, Canadian Pacific and Austral populations of A. simplex C were found to be genetically rather differentiated from one another (average DNei = 0.08), contrasting with the remarkable genetic homogeneity detected within both A. simplex s. str. and A. pegreffii (average DNei about 0.01). Accordingly, a lower amount of gene flow was estimated within A. simplex C (Nm = 1.6) than within the other 2 species (Nm = 5.4 and 17.7, respectively). Anisakis simplex C showed the highest average values of genetic variability with respect to both A. simplex s. str. and A. pegreffii, e.g., expected mean heterozygosity. Hr = 0.23, 0.16, and 0.11, respectively, in the 3 species. Data on geographic distribution and hosts of the 3 members so far detected in the A. simplex complex are given. Their ecological niche is markedly differentiated, with a low proportion of hosts shared. Intermediate and definitive hosts of A. simplex s. str. and A. pegreffii appear to belong to distinct food webs, benthodemersal, and pelagic, respectively; this would lead to different transmission pathways for the parasites.

[Cucculanus bioccai n. sp. (nematoda: cucullanidae), parasite of Mugil cephalus L]. / Cucullanus bioccai n. sp. (Nematoda: Cucullanidae), parassita di Mugil cephalus L.

Cucullanus bioccai n. sp. described from the intestine of Mugil cephalus caught in Lake Sabaudia (Latina, Italy) is compared with C. dodsworthi and C. mugili parasites of mullets. It differs from C. dodsworthi mainly for the position of the 1st pair of precloacal papillae, the position of vulva, the shape of gubernaculum, the measurements of eggs; from C. mugili for the number of papillae, the position of the 1st pair of precloacal papillae, the conformation of cloaca and the position of vulva.

[Tyrrhenia blennii g.n. sp. n. (Hemiurata : Halipegidae Poche, 1925) parasite of Blennius gattorugine and Blennius sanguinolentus]. / Tyrrhenia blennii g.n. sp. n. (Hemiurata: Halipegidae Poche, 1925) parassita di Blennius gattorugine e Blennius sanguinolentus

Trematodes recovered from Blennius gattorugine and Blennius sanguinolentus from the Gulf of Gaeta, Italy, are described and figured as Tyrrhenia blennii g.n. sp.n. The new genus differs from other members of the Arnolinae Skrjabin and Guschanskaja, 1958 (Halipegidae Poche, 1925) chiefly in having acetabulum equatorial, receptaculum seminis uterinum present and eggs without filaments. The diagnosis of the new genus Tyrrhenia and a key to genera of Arnolinae are given.

[New parasite identified in Blennius sanguinolentus Pallas, 1811: Schikhobalotrema longivesiculatum sp. n (Haplosplanchnidae Poche, 1925)]. / Nuovo reperto parassitologico in Blennius sanguinolentus Pallas, 1811: Schikhobalotrema longivesiculatum sp.n. (Haplosplanchnidae Poche, 1925)

Schikhobalotrema longivesiculatum sp.n from Blennius sanguinolentus Pallas, 1811 at Gulf of Gaeta (Italy) is described, figured and compared with other species of the genus Schikhobalotrema Skrjabin et Guschanskaja, 1955. Schikhobalotrema longivesiculatum differs from Schikhobalotrema obtusa (Linton, 1916) Skrjabin et Guschanskaja, 1955, especially for sucker ratio, lobed ovary, seminal vesicle coiled and in larger size of eggs; from Schikhobalotrema pomacentri (Manter, 1937) Skrjabin et Guschanskaja, 1955 for lobed ovary, elongated seminal receptacle, smaller vitelline follicles and coiled seminal vesicle; from Schikhobalotrema sparisomae (Manter, 1937) Skrjabin et Guschanskaja, 1955 for elongated seminal receptacle, coiled seminal vesicle and extent of escretory vesicle.

[Atrispinum mormyri (Lorenz, 1878) n. comb. (Microcotylidae: Atriasterinae) parasites of Lithognathus mormyrus (L.)]. / Atrispinum mormyri (Lorenz, 1878) n. comb. (Microcotylidae: Atriasterinae) parassita di Lithognathus mormyrus (L.).

Atrispinum mormyri (Lorenz, 1878) n. comb. is proposed for Microcotyle mormyri collected on the gills of Lithognathus mormyrus (L.), from the Adriatic and Tyrrhenean Seas on the base of the structure of the genital atrium and the presence of a single vagina with dorsal aperture. The species is included in the keys given by Maillard e Noisy (1978-79) for the species grouped into the genus Atrispinum.

[Acanthocephalan Paracanthocephaloides soleae (Porta, 1905) n. comb. (Arhythmacanthidae: Paracanthocephaloidinae) parasites of Solea impar Benn]. / Paracanthocephaloides soleae (Porta, 1905) n. comb. (Arhythmacanthidae: Paracanthocephaloidinae) acantocefalo parassita di Solea impar Benn.

The authors redescribe an acanthocephalan found in the intestine of Solea impar Benn. formerly considered as belonging to the species Acanthocephaloides soleae (Porta, 1905) Petrotschenko, 1956. The systematic position of the species soleae is discussed. For the absence of the trunk spines and for the morphology of the proboscis it is assigned to the genus Paracanthocephaloides Golvan, 1969 as Paracanthocephaloides soleae (Porta, 1905) n. comb.

[A new species of Plagioporus (Caudotestis) tyrrhenicus sp.n. and its 2 new parasitologic findings in Blennius pavo Risso, 1810]. / Su di una nuova specie Plagioporus (Caudotestis) tyrrhenicus sp.n. e su due nuovi reperti parassitologici in Blennius pavo Risso, 1810.

In a survey of the helminth parasites of Blennius pavo Risso, 1810 three different species of digenea were collected. Plagioporus (Caudotestis) tyrrhenicus sp.n. is described, figured and compared with other species of the subgenus Plagioporus (Caudotestis) Issaitchikov, 1928. Plagioporus (Caudotestis) tyrrhenicus differs from P. (Caudotestis) azurionis Yamaguti, 1951 in the position of cirrus sac, in sucker ratio and size of the eggs; from P. (Caudotestis) sinitzini Mueller, 1934 for extent of excretory bladder and size of the eggs; from P. (Caudotestis) synagris Yamaguti, 1952 for size of the pharynx and oesophagus, extent of the vitellaria and size of the eggs. Lepocreadium album (Stossich, 1890) Stossich, 1904 is redescribed, figured and recorded for the first time in Blennius pavo. Deretrema sp. is figured and recorded for the first time in the same host.

[New faunal and biological observations on ticks in Abruzzo]. / Nuove osservazioni faunistiche e biologiche sulle zecche d'Abruzzo. (Nota i).

Ticks collected during the years 1975-76 in Abruzzo (Prov. l'Aquila and Chieti) Italy are reported. The following species have been identified: Ixodes canisuga, Ixodes frontalis, Ixodes hexagonus, Ixodes ricinus, Dermacentor marginatus, Haemaphysalis sulcata, Rhipicephalus bursa, Rhipicephalus sanguineus, Hyalomma marginatum. New hosts are: Felis catus for Ixodes canisuga; Scolopax rusticola, Motacilla flava, Corvus cornix for Ixodes frontalis; Sciurus vulgaris for Haemaphysalis punctata; Garrulus glandarius for Haemaphysalis sulcata. For Italy the following records are new: hosts: Corvus frugilegus for Ixodes frontalis; Coturnix coturnix and Alauda arvensis for Haemaphysalis sulcata; immature stages: Ixodes canisuga on Vulpes vulpes; Ixodes frontalis on Turdus merula; Haemaphysalis punctata on Coturnix coturnix, Phasianus colchicus, Erinaceus europaeus, Lepus europaeus; Accordingly numerous species, hosts and seasonal records are new for Abruzzo.

[Parasitic fauna of Salmo trutta L. of the Tirino river. I. Redescription of Dentitruncus truttae Sinzar, 1955 and considerations on the genus Dentitruncus Sinzar, 1955]. / Parassitofauna di Salmo trutta L. del fiume Tirino. Nota I. Ridescrizione di Dentitruncus truttae Sinzar, 1955 e considerazioni sul genere Dentitruncus Sinzar, 1955.

Dentitruncus truttae Sinzar, 1955 is redescribed and figured from specimens from Salmo truttae L. collected in the Tirino river (L'Aqula-Italy). The diagnosis of the genus Dentitruncus is completed and the characteristics separating Dentitruncus Sinzar, 1955 from Pseudorhadinorhynchus Achmerov e Drombrowskaja-Achmerova, 1941 are discussed.

Digeneans of fishes from the Adriatic Sea with a description of Lecithaster atherinae n. sp. from Atherina (Hepsetia) boyeri.

A collection of whole mount preparations of digeneans was studied. The parasites were collected from several species of fishes caught in a fishing area of the South Adriatic Sea. A host-parasite list is given. Twenty species of fish were analysed and twenty-seven species of digeneans were found, twenty of which had previously been described in the same host, and six of which were observed in new hosts and/or localities. One digenean, hitherto undescribed, is illustrated in this paper and described as Lecithaster atherinae n.sp. The new species can be distinguished from L. bombayensis by the testes not being lobed; from L. extralobus by having four rather than five ovarian lobes; from L. indicus and L. maeoticus by the ovarian lobes not being finger-like; from L. leiostomi by having definitely smaller eggs.

[Parasites of Salmo trutta L. from the Titino River. Part III. Histological observations of parasites of the intestinal tract]. / Parassitofauna di Salmo trutta L. del Fiume Tirino. nota III - osservazioni istologiche sui parassiti reperiti a livello intestinale.

During researches on helminth parasites of Salmo trutta L. from the River Tirino (L'Aquila - Italy) histological studies of the intestinal tract of brown trout infected by the following species: Crowcrocaecum testiobliquum (Wisnewski, 1932) Skrjabin e Koval, 1956; Cyathocephalus truncatus (Pallas, 1781);o Truttaedacnitis truttae (Fabricius, 1794) Petter, 1974 and Dentitruncus truttae Sinzar, 1955 have been carried out. The attachment of the single species and the histological changes in the host gut due to parasite species have been described.

[Parasites of Salmo trutta L. from the Tirino River. Part IV. Intermediate hosts of Cyathocephalus truncatus (Pallas, 1781) and Dentitruncus truttae Sinzar, 1955]. / Parassitofauna di Salmo trutta L. del Fiume Tirino. nota IV - Ricerca degli ospiti intermedi di Cyathocephalus truncatus (Pallas, 1781) e Dentitruncus truttae Sinzar, 1955.

During studies on helminth parasites of brown trout (Salmo trutta L.) from the river Tirino (L'Aquila - Italy), the intermediate hosts of Cyathocephalus truncatus (Pallas, 1781) and Dentitruncus truttae Sinzar, 1955 have been searched for. A total of 15,444 amphipoda belonging to the following 3 species: Echinogammarus roco Karman, 1973, Echinogammarus tibaldii Pinkster and Stock, 1970, and Gammarus italicus Goedmakers and Pinkster, 1977, have been dissected. E. roco, E. tibaldii and G. italicus were found infected with procercoid of Cyathocephalus truncatus (new hosts record and first procercoid record in Italy). E. roco, E. tibaldii and G. italicus were found infected with acanthella and cystacanth of Dentitruncus truttae (first record of intermediate hosts). Accordingly the ecology of the cestod C. truncatus and of the acanthocephalan D. truttae in their intermediate hosts has been studied considering principally the incidence and the seasonal occurence of the parasites.

[A new Acanthocephala Breizacanthus ligur sp. n. (Palaeacanthocephala: Arhythmacanthidae Yamatugi, 1935) parasite of some species of benthic fishes from the Ligurian Sea]. / Su di un nuovo acantocefalo Breizacanthus ligur sp.n. (Palaeacanthocephala: Arhythmacanthidae Yamaguti, 1935) parassita di alcune specie di pesci bentonici del Mar Ligure

Breizacanthus ligur sp.n. is described and figured from several benthic fishes from the Ligurian Sea. The host species are: Argentina sphyraena, Chlorophthalmus agassizi, Gadiculus argenteus, Phycis blennoides, Coelorhynchus coelorhynchus, Capros aper, Callionymus phaeton, Helicolenus dactylopterus. The parasites were considered as belonging to the family Arhythmacanthidae Yamaguti, 1935 and to the genus Breizancanthus Golvan, 1969. Breizancanthus ligur differs from the only two known species of the genus B. irenae and B. chabaudi for the number of longitudinal rows of hooks and-or numbers of hooks in each longitudinal row, arrangment of cement glands, length of body and lenght of male genital apparatus ratio, lenght of female genital apparatus and shape of embroyophore.