Esteban Montero - Academia.edu (original) (raw)

Papers by Esteban Montero

Parasites & Vectors, 2020

BackgroundMicrocotyle erythrinivan Beneden & Hesse, 1863 (Platyhelminthes: Monogenea) and other c... more BackgroundMicrocotyle erythrinivan Beneden & Hesse, 1863 (Platyhelminthes: Monogenea) and other closely related species of the genus are often considered as cryptic. Records in hosts other than the type-host with no species confirmation by molecular analyses have contributed to this situation.MethodsGill parasites of five sparid fishes,Boops boops(L.),Pagellus erythrinus(L.),P. acarne(Risso), Dentex dentex(L.) andPagrus pagrus(L.), from the Western Mediterranean off Spain were collected. Specimens ofMicrocotylespp. were characterised both molecularly and morphologically. Partial fragments (domains D1-D3) of the28SrRNA gene and the cytochromecoxidase subunit 1 (cox1) gene were amplified and used for molecular identification and phylogenetic reconstruction. Principal components analysis was used to look for patterns of morphological separation.ResultsMolecular analyses confirmed the identity of three species:M. erythriniexP. erythrinusandPa. pagrus;M. isyebiBouguerche, Gey, Justine & ...

Deep Sea Research Part I: Oceanographic Research Papers, 2019

In the last decades fishing activities have spread from coastal to deeper waters with serious eff... more In the last decades fishing activities have spread from coastal to deeper waters with serious effects on the deepsea ecosystems and its fauna, which are considered to be highly susceptible to these impacts. The implementation of protection measures is necessary, but the knowledge on this biome is scant, and often limited to species of commercial value. To the best of our knowledge, this study is the first survey to describe and analyse parasite infracommunities of the deep-sea fish Notacanthus bonaparte sampled from three bathymetric strata between the upper and lower slope in the western Mediterranean Sea (Balearic Sea, Spain). The aim of this work was to assess the effect of host specific parameters as well as environmental conditions and spatial and temporal variation on the composition and structure of the parasite communities. We have found poor parasite infracommunities, usually described rather for bathypelagic fishes than observed in fishes with benthic feeding habits such as N. bonaparte, in which two out of five species are considered as accidental infections. The infracommunity composition is determined by the factors, depth and maturity status (size). The dominating taxon, cucullanid larvae, seem to be accumulated throughout the life of the host showing higher abundances in larger fish in deeper waters on the middle and lower slope. The prevalence and abundance of this parasite could be linked to increased water turbidity and it is supposed that these larvae are free-living in the sediment being ingested by N. bonaparte when feeding on benthic organisms. The results suggest that N. bonaparte acts as important intermediate host for this taxon though, the final host is still unknown. The single monogenean species Tinrovia mamaevi was mainly recorded in the upper slope and its higher prevalence in this depth range could be related to higher host densities observed in these depths. The prevalence and abundance of this parasite species could be linked to temperature and salinity, and although measured variations for these parameters were marginal it is supposed that these and probably further additional abiotic factors may influence its distribution pattern. Considering previously published diet data this study indicates potential pathways other than those expected for parasites transmitted via the food web using N. bonaparte as intermediate and definitive host.

Parasites & Vectors, 2019

Background: Despite their complex life-cycles involving various types of hosts and free-living st... more Background: Despite their complex life-cycles involving various types of hosts and free-living stages, digenean trematodes are becoming recurrent model systems. The infection and penetration strategy of the larval stages, i.e. cercariae, into the fish host is poorly understood and information regarding their entry portals is not well-known for most species. Cardiocephaloides longicollis (Rudolphi, 1819) Dubois, 1982 (Digenea, Strigeidae) uses the gilthead seabream (Sparus aurata L.), an important marine fish in Mediterranean aquaculture, as a second intermediate host, where they encyst in the brain as metacercariae. Labelling the cercariae with in vivo fluorescent dyes helped us to track their entry into the fish, revealing the penetration pattern that C. longicollis uses to infect S. aurata. Methods: Two different fluorescent dyes were used: carboxyfluorescein diacetate succinimidyl ester (CFSE) and Hoechst 33342 (NB). Three ascending concentrations of each dye were tested to detect any effect on labelled cercarial performance, by recording their survival for the first 5 h post-labelling (hpl) and 24 hpl, as well as their activity for 5 hpl. Labelled cercariae were used to track the penetration points into fish, and cercarial infectivity and later encystment were analysed by recording brain-encysted metacercariae in fish infected with labelled and control cercariae after 20 days of infection. Results: Although the different dye concentrations showed diverse effects on both survival and activity, intermediate doses of CFSE did not show any short-term effect on survival, permitting a brighter and longer recognition of cercariae on the host body surface. Therefore, CFSE helped to determine the penetration points of C. longicollis into the fish, denoting their aggregation on the head, eye and gills region, as well as on the dorsal fin and the lower side. Only CFSE-labelled cercariae showed a decreased number of encysted metacercariae when compared to control. Conclusions: Our study suggests that CFSE is an adequate labelling method for short-term in vivo studies, whereas NB would better suit in vivo studies on long-term performance. Cardiocephaloides longicollis cercariae seem to be attracted to areas near to the brain or those that are likely to be connected to migration routes to neuronal canals.

International Journal for Parasitology, 2019

Highlights  Morpho-molecular incongruences were found on diplectanid richness and host specifici... more Highlights  Morpho-molecular incongruences were found on diplectanid richness and host specificity.  Only five species were detected with molecular methods although 11 have been described.  Two new genera are proposed for diplectanids from Mediterranean sciaenids.  Most Diplectaninae gen. spp. are mainly generalists of Mediterranean sciaenids.  Genetic structure suggests different cross-infection potential amongst sciaenids.

Systematic parasitology, Jun 26, 2017

A new microcotylid, Tinrovia mamaevi n. sp. (Monogenea: Polyopisthocotylea), is described from th... more A new microcotylid, Tinrovia mamaevi n. sp. (Monogenea: Polyopisthocotylea), is described from the gills of Notacanthus bonaparte Risso (Notacanthiformes: Notacanthidae), sampled in the Western Mediterranean and North East Atlantic. This species is allocated to the subfamily Syncoelicotylinae Mamaev & Zubchenko, 1978 due to the possession of a symmetrical haptor with two separate frills. The clamps in T. mamaevi n. sp. are of the "microcotylid" type, arranged in two distinct lateral haptoral frills; the genital atrium and the copulatory organ are armed and the vaginal pore is unarmed. The new species differs from the type- and only species of the genus, T. papiliocauda Mamaev, 1987, in having a shorter and narrower haptor with a smaller number of clamps. Clamps are also smaller in the new species, testes are more numerous, the genital atrium is smaller, divided into two lateral lobes (instead of five) with a smaller number of spines and the eggs have a short and a long fil...

Parasites & Vectors, 2015

Background: Accacoelium contortum (Rudolphi, 1819) Monticelli, 1893 is a frequent but poorly know... more Background: Accacoelium contortum (Rudolphi, 1819) Monticelli, 1893 is a frequent but poorly known trematode found on gills, pharynx and digestive tract of the ocean sunfish Mola mola (L.). Although the morphology of A. contortum agrees with that of a typical endoparasitic trematode, with two relatively small suckers and no large holdfasts, this parasite is normally ectoparasitic. The main objective of this paper is to explore this peculiar host-parasite relationship. Methods: A total of 106 ocean sunfish were examined for the presence of A. contortum. The oropharyngeal chamber (gills and pharynx) and the digestive tract were analysed. As the previous descriptions of this species seem to be based on contracted specimens, for the morphological study the parasites were killed using two methods: with hot 70 % ethanol (with relaxed bodies) and with 70 % ethanol at room temperature (with contracted bodies). For histological studies, samples from fresh fish with parasitised left gills, pharynx and digestive tract were fixed in buffered 10 % formalin. For molecular studies the 18S, 28S and ITS-2 sequences were provided and compared with the available data in GenBank®. Results: New information on the morphology of A. contortum and on the parasite-related response and pathological alterations in the host are given. New diagnostic traits for some structures are provided: e.g. tegumental papillae of the forebody with apical digitiform swellings and mouth surrounded by a circum-oral crown of simple papillae. The length of the ventral sucker peduncle and the position of the vitellarium were found to be associated with the contraction degree of the specimen. Immature individuals of this species are described for the first time. An intense proliferative inflammatory response of host gill and pharynx epithelium at the host-parasite interface was detected and parasites became partially covered by overgrowths of host tissues. Conclusions: The induction of prominent histological alterations associated with A. contortum seems to be an adaptation to the external environment, an unusual location for trematodes.

Systematic Parasitology, 2015

Systematic Parasitology, 2014

Systematic Parasitology, 2009

Saccocoelium Looss, 1902 is revised and a key to its recognised species is presented. S. obesum L... more Saccocoelium Looss, 1902 is revised and a key to its recognised species is presented. S. obesum Looss, 1902 (type-species) and S. tensum Looss, 1902 are redescribed based on material from Liza spp. (Pisces: Mugilidae) in Spanish Mediterranean and, in the case of the former, Bulgarian Black Sea waters. Two new species, S. cephali n. sp. and S. currani n. sp., are described from Mugil cephalus L. in Spanish Mediterranean waters. S. gohari Ramadan, Saoud, Ashour & Mansour, 1989b is recognised and commented upon.

Scientia Marina, 2010

The usefulness of fish parasite communities as bioindicators of environmental stress was tested o... more The usefulness of fish parasite communities as bioindicators of environmental stress was tested on two benthic fish species, the red mullet (Mullus barbatus) and the spotted flounder (Citharus linguatula), during the spring of 2006 at two sites of the Catalan coast (northwestern Mediterranean): an anthropogenic-impacted area located close to the city of Barcelona, and a less polluted area close to Blanes (Girona). Gonadosomatic and hepatosomatic indices and condition factor were determined for the fishes caught. Prevalence, mean intensity, mean abundance and species richness of the parasites found in the survey were calculated for both species and locations, and the main histological alterations were recorded. Cysts of unknown aetiology and intestinal coccidians were reported only in red mullets from the area close to Barcelona, which were highly parasitized by the digenean Opecoeloides furcatus and the nematode Capillaria sp. However, a higher prevalence of Ichthyophonus sp. was reported in the spotted flounder from Blanes. Cysts of unknown aetiology, some nematodes and Ichthyophonus sp. may be associated with pollution.

Parasitology International, 2011

This study describes a new aporocotylid genus and species, Skoulekia meningialis n. gen., n. sp. ... more This study describes a new aporocotylid genus and species, Skoulekia meningialis n. gen., n. sp. which was detected in the ectomeningeal veins surrounding the optic lobes of the brain of the common two-banded seabream Diplodus vulgaris (Geoffroy Saint-Hilaire, 1817) from the Gulf of Valencia (Mediterranean Sea). A detailed morphological description of S. meningialis is provided, including drawings, measurements and scanning electron microscopy images as well as a phylogenetic study of S. meningialis and closely related taxa using DNA sequence data obtained from whole ITS2 and partial 18S and 28S rDNA regions. Morphology as well as molecular phylogeny strongly support the erection of a new genus and demonstrate its close relationship with the genera Psettarium (Goto & Ozaki, 1930) and Pearsonellum Overstreet & Køie, 1989. Skoulekia is the second aporocotylid genus described in the Sparidae, a family including economical important fishes. In contrast to the majority of the aporocotylids, which inhabit the heart or the blood vessels of the gills, S. meningialis inhabits the ectomeningeal veins surrounding the optic lobes. Eggs were found trapped within the gill vessels. Normally, blood fluke pathology is almost exclusively related to the eggs. However, in the case of S. meningialis, main histopathological alterations were related to the adult blood flukes which were found to cause mild localised meningitis.

Parasitology International, 2008

Marine Pollution Bulletin, 2012

We examined parasite populations and communities in the Mediterranean sentinel fish species, Mull... more We examined parasite populations and communities in the Mediterranean sentinel fish species, Mullus barbatus, sampled at a small-scale PCB gradient at the shelf sediments off Catalonian coasts of the Western Mediterranean. A recurrent feature at both the population and community level was the differentiation of the samples along the increasing PCB levels simultaneously registered in the sediments. Both directly transmitted ectoparasites and endoparasites with complex life-cycles transmitted via food chains exhibited a decrease in abundance with the increase in PCB levels. Parasite numerical responses translated into significant differences in infracommunity structure with decreasing predictability associated with increasing PCB levels. The abundance of two species, the specialist Opecoeloides furcatus and the generalist nematode Hysterothylacium fabri, contributed substantially to the observed dissimilarity between infracommunity samples along the gradient. The observed parasite responses to moderate levels of pollution were simultaneously validated by both chemical monitoring and effect biomarkers.

Journal of Parasitology, 2010

Journal of Parasitology, 2006

Journal of Parasitology, 2012

We describe a new heterophyid species, Ascocotyle (Ascocotyle) patagoniensis n. sp., based on spe... more We describe a new heterophyid species, Ascocotyle (Ascocotyle) patagoniensis n. sp., based on specimens collected from the intestines of the South American sea lion Otaria flavescens from Patagonia (Argentina). Ascocotyle (A.) patagoniensis n. sp. is distinguished from the other species of the subgenus by the number of circumoral spines, which are arranged in 2 rows of 18 to 23. The new species also differs from the other species in having a gonotyl without papillae. The specimens exhibited the widest seminal receptacle described for a species of this subgenus. Species of the subgenus Ascocotyle usually infect fish-eating birds or mammals in freshwater or brackish habitats. Ascocotyle (A.) patagoniensis n. sp. is the first species of the subgenus described from a marine mammal. However, no metacercariae of Ascocotyle spp. were found in 542 marine teleosts from 20 species collected in the same locality. The life cycle of the marine species from the Ascocotyle-complex infecting pinnipeds remains elusive.

Parasites & Vectors, 2020

BackgroundMicrocotyle erythrinivan Beneden & Hesse, 1863 (Platyhelminthes: Monogenea) and other c... more BackgroundMicrocotyle erythrinivan Beneden & Hesse, 1863 (Platyhelminthes: Monogenea) and other closely related species of the genus are often considered as cryptic. Records in hosts other than the type-host with no species confirmation by molecular analyses have contributed to this situation.MethodsGill parasites of five sparid fishes,Boops boops(L.),Pagellus erythrinus(L.),P. acarne(Risso), Dentex dentex(L.) andPagrus pagrus(L.), from the Western Mediterranean off Spain were collected. Specimens ofMicrocotylespp. were characterised both molecularly and morphologically. Partial fragments (domains D1-D3) of the28SrRNA gene and the cytochromecoxidase subunit 1 (cox1) gene were amplified and used for molecular identification and phylogenetic reconstruction. Principal components analysis was used to look for patterns of morphological separation.ResultsMolecular analyses confirmed the identity of three species:M. erythriniexP. erythrinusandPa. pagrus;M. isyebiBouguerche, Gey, Justine & ...

Deep Sea Research Part I: Oceanographic Research Papers, 2019

In the last decades fishing activities have spread from coastal to deeper waters with serious eff... more In the last decades fishing activities have spread from coastal to deeper waters with serious effects on the deepsea ecosystems and its fauna, which are considered to be highly susceptible to these impacts. The implementation of protection measures is necessary, but the knowledge on this biome is scant, and often limited to species of commercial value. To the best of our knowledge, this study is the first survey to describe and analyse parasite infracommunities of the deep-sea fish Notacanthus bonaparte sampled from three bathymetric strata between the upper and lower slope in the western Mediterranean Sea (Balearic Sea, Spain). The aim of this work was to assess the effect of host specific parameters as well as environmental conditions and spatial and temporal variation on the composition and structure of the parasite communities. We have found poor parasite infracommunities, usually described rather for bathypelagic fishes than observed in fishes with benthic feeding habits such as N. bonaparte, in which two out of five species are considered as accidental infections. The infracommunity composition is determined by the factors, depth and maturity status (size). The dominating taxon, cucullanid larvae, seem to be accumulated throughout the life of the host showing higher abundances in larger fish in deeper waters on the middle and lower slope. The prevalence and abundance of this parasite could be linked to increased water turbidity and it is supposed that these larvae are free-living in the sediment being ingested by N. bonaparte when feeding on benthic organisms. The results suggest that N. bonaparte acts as important intermediate host for this taxon though, the final host is still unknown. The single monogenean species Tinrovia mamaevi was mainly recorded in the upper slope and its higher prevalence in this depth range could be related to higher host densities observed in these depths. The prevalence and abundance of this parasite species could be linked to temperature and salinity, and although measured variations for these parameters were marginal it is supposed that these and probably further additional abiotic factors may influence its distribution pattern. Considering previously published diet data this study indicates potential pathways other than those expected for parasites transmitted via the food web using N. bonaparte as intermediate and definitive host.

Parasites & Vectors, 2019

Background: Despite their complex life-cycles involving various types of hosts and free-living st... more Background: Despite their complex life-cycles involving various types of hosts and free-living stages, digenean trematodes are becoming recurrent model systems. The infection and penetration strategy of the larval stages, i.e. cercariae, into the fish host is poorly understood and information regarding their entry portals is not well-known for most species. Cardiocephaloides longicollis (Rudolphi, 1819) Dubois, 1982 (Digenea, Strigeidae) uses the gilthead seabream (Sparus aurata L.), an important marine fish in Mediterranean aquaculture, as a second intermediate host, where they encyst in the brain as metacercariae. Labelling the cercariae with in vivo fluorescent dyes helped us to track their entry into the fish, revealing the penetration pattern that C. longicollis uses to infect S. aurata. Methods: Two different fluorescent dyes were used: carboxyfluorescein diacetate succinimidyl ester (CFSE) and Hoechst 33342 (NB). Three ascending concentrations of each dye were tested to detect any effect on labelled cercarial performance, by recording their survival for the first 5 h post-labelling (hpl) and 24 hpl, as well as their activity for 5 hpl. Labelled cercariae were used to track the penetration points into fish, and cercarial infectivity and later encystment were analysed by recording brain-encysted metacercariae in fish infected with labelled and control cercariae after 20 days of infection. Results: Although the different dye concentrations showed diverse effects on both survival and activity, intermediate doses of CFSE did not show any short-term effect on survival, permitting a brighter and longer recognition of cercariae on the host body surface. Therefore, CFSE helped to determine the penetration points of C. longicollis into the fish, denoting their aggregation on the head, eye and gills region, as well as on the dorsal fin and the lower side. Only CFSE-labelled cercariae showed a decreased number of encysted metacercariae when compared to control. Conclusions: Our study suggests that CFSE is an adequate labelling method for short-term in vivo studies, whereas NB would better suit in vivo studies on long-term performance. Cardiocephaloides longicollis cercariae seem to be attracted to areas near to the brain or those that are likely to be connected to migration routes to neuronal canals.

International Journal for Parasitology, 2019

Highlights  Morpho-molecular incongruences were found on diplectanid richness and host specifici... more Highlights  Morpho-molecular incongruences were found on diplectanid richness and host specificity.  Only five species were detected with molecular methods although 11 have been described.  Two new genera are proposed for diplectanids from Mediterranean sciaenids.  Most Diplectaninae gen. spp. are mainly generalists of Mediterranean sciaenids.  Genetic structure suggests different cross-infection potential amongst sciaenids.

Systematic parasitology, Jun 26, 2017

A new microcotylid, Tinrovia mamaevi n. sp. (Monogenea: Polyopisthocotylea), is described from th... more A new microcotylid, Tinrovia mamaevi n. sp. (Monogenea: Polyopisthocotylea), is described from the gills of Notacanthus bonaparte Risso (Notacanthiformes: Notacanthidae), sampled in the Western Mediterranean and North East Atlantic. This species is allocated to the subfamily Syncoelicotylinae Mamaev & Zubchenko, 1978 due to the possession of a symmetrical haptor with two separate frills. The clamps in T. mamaevi n. sp. are of the "microcotylid" type, arranged in two distinct lateral haptoral frills; the genital atrium and the copulatory organ are armed and the vaginal pore is unarmed. The new species differs from the type- and only species of the genus, T. papiliocauda Mamaev, 1987, in having a shorter and narrower haptor with a smaller number of clamps. Clamps are also smaller in the new species, testes are more numerous, the genital atrium is smaller, divided into two lateral lobes (instead of five) with a smaller number of spines and the eggs have a short and a long fil...

Parasites & Vectors, 2015

Background: Accacoelium contortum (Rudolphi, 1819) Monticelli, 1893 is a frequent but poorly know... more Background: Accacoelium contortum (Rudolphi, 1819) Monticelli, 1893 is a frequent but poorly known trematode found on gills, pharynx and digestive tract of the ocean sunfish Mola mola (L.). Although the morphology of A. contortum agrees with that of a typical endoparasitic trematode, with two relatively small suckers and no large holdfasts, this parasite is normally ectoparasitic. The main objective of this paper is to explore this peculiar host-parasite relationship. Methods: A total of 106 ocean sunfish were examined for the presence of A. contortum. The oropharyngeal chamber (gills and pharynx) and the digestive tract were analysed. As the previous descriptions of this species seem to be based on contracted specimens, for the morphological study the parasites were killed using two methods: with hot 70 % ethanol (with relaxed bodies) and with 70 % ethanol at room temperature (with contracted bodies). For histological studies, samples from fresh fish with parasitised left gills, pharynx and digestive tract were fixed in buffered 10 % formalin. For molecular studies the 18S, 28S and ITS-2 sequences were provided and compared with the available data in GenBank®. Results: New information on the morphology of A. contortum and on the parasite-related response and pathological alterations in the host are given. New diagnostic traits for some structures are provided: e.g. tegumental papillae of the forebody with apical digitiform swellings and mouth surrounded by a circum-oral crown of simple papillae. The length of the ventral sucker peduncle and the position of the vitellarium were found to be associated with the contraction degree of the specimen. Immature individuals of this species are described for the first time. An intense proliferative inflammatory response of host gill and pharynx epithelium at the host-parasite interface was detected and parasites became partially covered by overgrowths of host tissues. Conclusions: The induction of prominent histological alterations associated with A. contortum seems to be an adaptation to the external environment, an unusual location for trematodes.

Systematic Parasitology, 2015

Systematic Parasitology, 2014

Systematic Parasitology, 2009

Saccocoelium Looss, 1902 is revised and a key to its recognised species is presented. S. obesum L... more Saccocoelium Looss, 1902 is revised and a key to its recognised species is presented. S. obesum Looss, 1902 (type-species) and S. tensum Looss, 1902 are redescribed based on material from Liza spp. (Pisces: Mugilidae) in Spanish Mediterranean and, in the case of the former, Bulgarian Black Sea waters. Two new species, S. cephali n. sp. and S. currani n. sp., are described from Mugil cephalus L. in Spanish Mediterranean waters. S. gohari Ramadan, Saoud, Ashour & Mansour, 1989b is recognised and commented upon.

Scientia Marina, 2010

The usefulness of fish parasite communities as bioindicators of environmental stress was tested o... more The usefulness of fish parasite communities as bioindicators of environmental stress was tested on two benthic fish species, the red mullet (Mullus barbatus) and the spotted flounder (Citharus linguatula), during the spring of 2006 at two sites of the Catalan coast (northwestern Mediterranean): an anthropogenic-impacted area located close to the city of Barcelona, and a less polluted area close to Blanes (Girona). Gonadosomatic and hepatosomatic indices and condition factor were determined for the fishes caught. Prevalence, mean intensity, mean abundance and species richness of the parasites found in the survey were calculated for both species and locations, and the main histological alterations were recorded. Cysts of unknown aetiology and intestinal coccidians were reported only in red mullets from the area close to Barcelona, which were highly parasitized by the digenean Opecoeloides furcatus and the nematode Capillaria sp. However, a higher prevalence of Ichthyophonus sp. was reported in the spotted flounder from Blanes. Cysts of unknown aetiology, some nematodes and Ichthyophonus sp. may be associated with pollution.

Parasitology International, 2011

This study describes a new aporocotylid genus and species, Skoulekia meningialis n. gen., n. sp. ... more This study describes a new aporocotylid genus and species, Skoulekia meningialis n. gen., n. sp. which was detected in the ectomeningeal veins surrounding the optic lobes of the brain of the common two-banded seabream Diplodus vulgaris (Geoffroy Saint-Hilaire, 1817) from the Gulf of Valencia (Mediterranean Sea). A detailed morphological description of S. meningialis is provided, including drawings, measurements and scanning electron microscopy images as well as a phylogenetic study of S. meningialis and closely related taxa using DNA sequence data obtained from whole ITS2 and partial 18S and 28S rDNA regions. Morphology as well as molecular phylogeny strongly support the erection of a new genus and demonstrate its close relationship with the genera Psettarium (Goto & Ozaki, 1930) and Pearsonellum Overstreet & Køie, 1989. Skoulekia is the second aporocotylid genus described in the Sparidae, a family including economical important fishes. In contrast to the majority of the aporocotylids, which inhabit the heart or the blood vessels of the gills, S. meningialis inhabits the ectomeningeal veins surrounding the optic lobes. Eggs were found trapped within the gill vessels. Normally, blood fluke pathology is almost exclusively related to the eggs. However, in the case of S. meningialis, main histopathological alterations were related to the adult blood flukes which were found to cause mild localised meningitis.

Parasitology International, 2008

Marine Pollution Bulletin, 2012

We examined parasite populations and communities in the Mediterranean sentinel fish species, Mull... more We examined parasite populations and communities in the Mediterranean sentinel fish species, Mullus barbatus, sampled at a small-scale PCB gradient at the shelf sediments off Catalonian coasts of the Western Mediterranean. A recurrent feature at both the population and community level was the differentiation of the samples along the increasing PCB levels simultaneously registered in the sediments. Both directly transmitted ectoparasites and endoparasites with complex life-cycles transmitted via food chains exhibited a decrease in abundance with the increase in PCB levels. Parasite numerical responses translated into significant differences in infracommunity structure with decreasing predictability associated with increasing PCB levels. The abundance of two species, the specialist Opecoeloides furcatus and the generalist nematode Hysterothylacium fabri, contributed substantially to the observed dissimilarity between infracommunity samples along the gradient. The observed parasite responses to moderate levels of pollution were simultaneously validated by both chemical monitoring and effect biomarkers.

Journal of Parasitology, 2010

Journal of Parasitology, 2006

Journal of Parasitology, 2012

We describe a new heterophyid species, Ascocotyle (Ascocotyle) patagoniensis n. sp., based on spe... more We describe a new heterophyid species, Ascocotyle (Ascocotyle) patagoniensis n. sp., based on specimens collected from the intestines of the South American sea lion Otaria flavescens from Patagonia (Argentina). Ascocotyle (A.) patagoniensis n. sp. is distinguished from the other species of the subgenus by the number of circumoral spines, which are arranged in 2 rows of 18 to 23. The new species also differs from the other species in having a gonotyl without papillae. The specimens exhibited the widest seminal receptacle described for a species of this subgenus. Species of the subgenus Ascocotyle usually infect fish-eating birds or mammals in freshwater or brackish habitats. Ascocotyle (A.) patagoniensis n. sp. is the first species of the subgenus described from a marine mammal. However, no metacercariae of Ascocotyle spp. were found in 542 marine teleosts from 20 species collected in the same locality. The life cycle of the marine species from the Ascocotyle-complex infecting pinnipeds remains elusive.