Metazoan parasite communities of wild Leporinus friderici (Characiformes: Anostomidae) from Amazon River system in Brazil

This study compared the structure of metazoan parasite communities in two populations of Leporinus friderici from two rivers of the Amazon River system in Brazil. Jainus leporini, Urocleidoides paradoxus, Urocleidoides sp., Tereancistrum parvus, Tereancistrum sp., Clinostomum marginatum, Procamallanus (Spirocamallanus) inopinatus, Contracaecum sp., Octospiniferoides incognita and Ergasilus sp. were found in both hosts. There were differences in species richness of parasites, Shannon index and the evenness between both host populations, because the parasite community showed a similarity of only 33%. Parasites of both host populations had an aggregated dispersion. Host size also contributes to the differences between the populations of hosts investigated, and the feeding habit contributes to the occurrence of endoparasites in L. friderici, an intermediate host for these parasites. The existence of variation in infracommunity and community of parasites for the same host species from different localities indicates the presence of an uneven distribution in terms of species and density of parasites, which are intermediate hosts, and some of them constitute food items for L. friderici in the localities surveyed.     

Diversity of parasites in Cichlasoma amazonarum Kullander, 1983 during rainy and dry seasons in eastern Amazon (Brazil)

This study investigated the influence of the rainy and dry seasons on the parasite communities of Cichlasoma amazonarum (Kullander, 1983) in a tributary of the Amazon River system, northern Brazil. Of 112 fish examined, 95.5% were parasitized by Ichthyophthirius multifiliis, Piscinoodinium pillulare, Gussevia disparoides, Posthodiplostomum sp., Procamallanus (Spirocamallanus) inopinatus, and Echinorhynchus paranensis, as well as by the Glossiphoniidae leech. Ichthyophthirius multifiliis and P. pillulare were the dominant parasite species, with I. multifiliis the most prevalent and abundant; the leech (Glossiphoniidae) was the least prevalent and least abundant. Parasites presented an aggregate dispersion pattern and seasonal variations in infestation levels, influenced by the environmental conditions in the rainy season. Variation in the parasite dynamics created overall changes in the parasite communities, characterized by greater diversity, species richness and evenness during the rainy season. However, there was a high similarity (99.8%) in the parasite community structure between the rainy and dry seasons. During the dry season the hosts had predominantly 1–3 parasite species compared to 3–4 parasites in the rainy season. Some parasites in the eastern Amazon undergo population changes relating to seasonality. These results thus indicate the correct season to apply adequate prophylactic measures to reduce negative impacts of parasites in this wild ornamental fish when captured.     

Incipient genetic divergence or cryptic speciation? Procamallanus (Nematoda) in freshwater fishes (Astyanax)

Hosts provide the main environmental traits parasites have to deal with, resulting in covariation between both associates at both micro- and macro-evolutionary scales; phylogenetic analyses of highly host-specific parasites have shown that parasite and host phylogeny might be highly congruent, and adaptation of a host species to new environments may lead to concordant changes of their parasites. Procamallanus (Spirocamallanus) neocaballeroi is a highly host-specific parasitic nematode of the Neotropical freshwater fish genus Astyanax in Mexico. One of the host species of the nematode is the emblematic Mexican tetra, A. mexicanus, which exhibits two contrasting phenotypes, a cave-dwelling morph (with troglomorphic features), and the surface-dwelling morph; other congeneric species inhabit rivers and lakes, and some of them occur in sympatry, displaying trophic specializations. Here, we explored the hypothesis that contrasting environments (surface rivers vs cave rivers), and host morphological divergence (sympatric ecomorphs in a lacustrine environment) might result in the divergence of their parasites, even though the hosts maintain a cohesive genetic structure as the same species. To test the hypothesis, several populations of Astyanax spp. were sampled to search for P. (S.) neocaballeroi. The nematode was found in 10 of the 52 sampled sites; two localities corresponded to cave populations. The phylogenetic analysis based on COI sequences yielded three major lineages for P. (S.) neocaballeroi. We found no concordance between the three lineages and the habitat where they occur in Astyanax mexicanus, even considering those living in drastic environmental conditions (caves), or between these lineages and lacustrine ecomorphs of Astyanax aeneus and A. caballeroi occurring in sympatry. Instead, genetic lineages of the nematode exhibit a clearer pattern of host species association and geographical distribution; our results showed that P. (S.) neocaballeroi is experiencing an incipient divergence although the morphological study of lineages shows no conspicuous differences.     

Seasonality affects the parasitism levels in two fish species in the eastern Amazon region

Fish parasite communities have strong interactions with the environment, the host fish, and the aquatic invertebrate communities. Thus, factors directly involving their different life cycles, such as different host populations and environments, as well as seasonal fluctuations in water levels can cause different responses. The main factors structuring parasite communities may be the hydrodynamic variations, together with seasonal variations in the availability of infectious stages of parasites in the environment. The purpose of this study was therefore to investigate the influence of the rainy and dry seasons on parasite infracommunities in fish species in the Amazon River System of Brazil. Between October 2009 and April 2011, specimens of Colossoma macropomum and Colossoma macropomum × Piaractus brachypomus hybrids (tambatinga) were examined for the presence of parasites. The parasite communities were similar in these two species that both showed aggregate dispersion, although the hybrid specimens were less parasitized. For both hosts, the Brillouin diversity, species richness, evenness and Berger‐Parker dominance indices were similar in the rainy season and dry season, except that the Berger‐Parker dominance index for the C. macropomum × P. brachypomus hybrid was higher during the dry season. Ichthyophthirius multifiliis was the dominant parasite, followed by Piscinoodinium pillulare, in both hosts. However, C. macropomum had a higher prevalence and abundance in the dry season, while in the C. macropomum × P. brachypomus hybrid, only the I. multifiliis prevalence increased. The abundance of monogenean species (Anacanthorus spathulatus, Linguadactyloides brinkmanni, Mymarothecium and Notozothecium janauachensis) was higher during the dry season in the gills of C. macropomum. Despite overdispersion of the lernaeid Perulernaea gamitanae, a seasonal pattern was seen only in the C. macropomum × P. brachypomus hybrid, with higher prevalence in the rainy season. The low prevalence and abundance of the ectoparasites Tetrahymena sp., Trichodina sp. and Braga patagonica, as well as of the endoparasites Procamallalus (Spirocamallanus) inopinatus and Neoechinorhynchus buttnerae, were not affected by seasonality. This information is applicable in farming practice for these economically important fish, as it indicates the best time for prophylactic management and treatment against parasites, in order to prevent economic losses in fish farms.     

The importance of gobies (Gobiidae,Teleostei) as hosts and transmitters of parasites in the SW Baltic

The parasite fauna of five goby species (Gobiidae, Teleostei) was investigated in the Baltic Sea during the period 1987 to 1990. 13 parasite species were found in samples from the Lübeck Bight:Bothriocephalus scorpii, Schistocephalus sp. (Cestoda);Cryptocotyle concavum, Cryptocotyle lingua, Podocotyle atomon, Derogenes varicus (Digenea);Hysterothylacium sp. (cf.auctum),Contracaecum sp.,Anisakis simplex (Nematoda);Corynosoma sp.,Echinorhynchus gadi, Neoechinorhynchus rutili, Pomphorhynchus laevis (Acanthocephala). The number of parasite species were: 10 in the sand gobyPomatoschistus minutus, 8 in the black gobyGobius niger, 7 in the two-spotted gobyGobiusculus flavescens, 6 in the common gobyPomatoschistus microps, and 5 in the painted gobyPomatoschistus pictus. Neoechinorhynchus rutili occurred only inP. minutus, andCorynosoma sp. only inG. niger. The extent to which the gobies were parasitized clearly depended on the respective ways of life and, moreover, on the kind of prey ingested by the hosts. Additionally, the age of the hosts might be important. The highest rate of parasitism, more than 60%, was reached byHysterothylacium sp. inG. niger and byCryptocotyle concavum inP. microps. Infestation incidence lay mostly below 40% which means a satellite species status (Holmes, 1991). The number of parasite species was highest in summer; the highest intensities of single parasites occurred in spring (Podocotyle atomon) or autumn (Crytocotyle concavum).Bothriocephalus scorpii, Hysterothylacium sp. andPodocotyle infested their juvenile hosts very early, but onlyHysterothylacium was accumulated byG. niger during its whole life span, whereasBothriocephalus persisted also in older gobies in low intensities. The cercariae ofCryptocotyle spp. penetrate actively into their hosts; all the other parasites named were transmitted in larval form by prey organisms which consisted mainly of planktonic and benthic crustaceans. The gobies were final hosts for only 5 parasites; but two species may be transmitted to larger fish, and 6 species to sea birds or mammals. The parasite community of the five gobies may possibly be taken to characterize the ecological quality of the environment of the Lübeck Bight.     

Metazoan parasites of African annual killifish (Nothobranchiidae): abundance,diversity, and their environmental correlates

Estimates of biodiversity and its global patterns are affected by parasite richness and specificity. Despite this, parasite communities are largely neglected in biodiversity estimates, especially in the tropics. We studied the parasites of annual killifish of the genus Nothobranchius that inhabit annually desiccating pools across the African savannah and survive the dry period as developmentally arrested embryos. Their discontinuous, non‐overlapping generations make them a unique organism in which to study natural parasite fauna. We investigated the relationship between global (climate and altitude) and local (pool size, vegetation, host density and diversity, and diversity of potential intermediate hosts) environmental factors and the community structure of killifish parasites. We examined metazoan parasites from 21 populations of four host species (Nothobranchius orthonotus, N. furzeri, N. kadleci, and N. pienaari) across a gradient of aridity in Mozambique. Seventeen parasite taxa were recorded, with trematode larval stages (metacercariae) being the most abundant taxa. The parasites recorded were both allogenic (life cycle includes non‐aquatic host; predominantly trematodes) and autogenic (cycling only in aquatic hosts; nematodes). The parasite abundance was highest in climatic regions with intermediate aridity, while parasite diversity was associated with local environmental characteristics and positively correlated with fish species diversity and the amount of aquatic vegetation. Our results suggest that parasite communities of sympatric Nothobranchius species are similar and dominated by the larval stages of generalist parasites. Therefore, Nothobranchius serve as important intermediate or paratenic hosts of parasites, with piscivorous birds and predatory fish being their most likely definitive hosts.     

Host–parasite interactions and vectors in the barn swallow in relation to climate change

Recent climate change has affected the phenology of numerous species, and such differential changes may affect host–parasite interactions. Using information on vectors (louseflies, mosquitoes, blackflies) and parasites (tropical fowl mite Ornithonyssus bursa, the lousefly Ornithomyia avicularia, a chewing louse Brueelia sp., two species of feather mites Trouessartia crucifera and Trouessartia appendiculata, and two species of blood parasites Leucozytozoon whitworthi and Haemoproteus prognei) of the barn swallow Hirundo rustica collected during 1971–2008, I analyzed temporal changes in emergence and abundance, relationships with climatic conditions, and changes in the fitness impact of parasites on their hosts. Temperature and rainfall during the summer breeding season of the host increased during the study. The intensity of infestation by mites decreased, but increased for the lousefly during 1982–2008. The prevalence of two species of blood parasites increased during 1988–2008. The timing of first mass emergence of mosquitoes and blackflies advanced. These temporal changes in phenology and abundance of parasites and vectors could be linked to changes in temperature, but less so to changes in precipitation. Parasites had fitness consequences for hosts because intensity of the mite and the chewing louse was significantly associated with delayed breeding of the host, while a greater abundance of feather mites was associated with earlier breeding. Reproductive success of the host decreased with increasing abundance of the chewing louse. The temporal decrease in mite abundance was associated with advanced breeding of the host, while the increase in abundance of the lousefly was associated with earlier breeding. Virulence by the tropical fowl mite decreased with increasing temperature, independent of confounding factors. These findings suggest that climate change affects parasite species differently, hence altering the composition of the parasite community, and that climate change causes changes in the virulence of parasites. Because the changing phenology of different species of parasites had both positive and negative effects on their hosts, and because the abundance of some parasites increased, while that of other decreased, there was no consistent temporal change in host fitness during 1971–2008.     

Two new species of Copepoda (Crustacea) parasitic on marine fishes

Two new species of parasitic Copepoda (Crustacea) are described and illustrated. Paeon australis n. sp. (Sphyriidae) is the first member of its genus discovered in Australian waters. It is parasitic on Rhinobates batillum, an elasmobranch fish. The other species, Lateracanthus curtus n. sp., is a parasite of an unspecified Macrourus, a deep-water teleost, taken in the northwestern Atlantic. The systematics of the genus Lateracanthus are discussed. Lateracanthus macrurus is relegated to the status of a species inquirenda.     

Helminth parasite diversity discloses age and sex differences in the foraging behaviour of southern lapwings (Vanellus chilensis)

Parasites with heteroxen cycles are important sources of information on the trophic relations of hosts. This is particularly instructive for species whose age‐based or sex‐based differences are hardly detected by behavioural observations. Here, we describe the helminth community of the omnivorous southern lapwing (Vanellus chilensis) and evaluate whether it is affected by the host's sex, age and body size. The species is sexually monomorphic in body length, but males are slightly heavier than females. We analysed 112 individuals collected in Curitiba, Brazil, in March 2010. All hosts were parasitized. The helminth community was composed of 10 species (the digeneans Leucochloridium parcum and Athesmia sp., the cestode Infula macrophallus, the acantocephalans Plagiorhynchus sp., Centrorhynchus sp., Mediorhynchus sp., and an unidentified Gigantorhynchida, and the nematodes Heterakis psophiae, Dispharynx nasuta and an unidentified Capillariidae), seven of which were novel reports for this host species. Prevalence ranged from <1% to 99%. Whereas I. macrophallus was the most prevalent species, D. nasuta showed the highest mean intensity and abundance of infection. The former was found in most hosts as single male–female pairs, suggesting the occurrence of intrasexual competition. The infracommunities of juvenile birds showed a higher parasite species richness than those of adult males and females, suggesting the exploitation of a wider array of prey. However, the three classes harboured seven parasite species. Differences in parasite diversity (lower in juveniles, intermediate in adult males and higher in adult females) reflect the evenness in the distribution of parasite specimens among taxa in each age–sex class and are compatible with differences in their foraging strategy. Finally, we conclude based on the cycles of the heteroxen species that southern lapwings preyed upon molluscs, coleopterans, woodlice and earthworms.     

Parasites of the introduced Amur sleeper, Perccottus glenii (Osteichthyes): Alpha-diversity of parasites and age of the host

Three age groups of the Amur sleeper have been studied: underyearlings (0+), two-year-olds (1+), and three- and four-year-olds (2+ and 3+). The long-cycle parasites prevalent in all three age groups are the merocercoids of Ophiotaenia europaea, third-stage juveniles of Spiroxys contortus, and metacercariae of Isthmiophora sp. and Prohemistomidae gen. sp. Different age groups of the Amur sleeper have different roles in the life cycle of O. Europaea. Underyearlings are second intermediate hosts of O. europaea, and Amur sleepers aged 1+ and older are parathenic hosts. The alpha-diversity of long-cycle parasites of the Amur sleeper increases with the age of the host.     

Diversity of the Schizophoria lineage (Brachiopoda: Orthida) in the Lower and Middle Devonian of Poland and adjacent areas

The nominative subgenus of Schizophoria (Brachiopoda, Orthida) is represented in the Lower and Middle Devonian of Poland and of the western Ukraine by six taxa: late Emsian Schizophoria (S.) interstrialis, late Eifelian S. (S.) schnuri biscissa, early Givetian S. (S.) schnuri schnuri, middle to late Givetian S. (S.) schnuri prohibita ssp.n., middle Givetian S. (S.) parvaepunctata and late Givetian S. (S.) sp.n. (unnamed for lack of sufficient material). Morphotypes referable to S. (S.) schnuri biscissa and to S. (S.) schnuri junkerbergiana co-occur in the same outcrop (not necessarily in the same levels), wherefore the separation of these subspecies may be maintained only if they are considered as chronosubspecies (unverifiable on the studied material) but not as geographic variants (hypothesis falsified by the studied material). A lectotype for S. (S.) interstrialis and a neotype for S. (S.) parvaepunctata are selected. Punctae diameter and density (either an important systematic character according to some authors or devoid of such value according to other ones) were investigated: they show important within-individual and within-sample variation, wherefore they cannot serve to distinguish related species. On the contrary, punctae character combinations are sufficiently constant to help differentiate subgenera or groups of species. In the studied material, three clusters are distinguished on the basis of the punctae characteristics: S. (Pachyschizophoria) and S. (S.) parvaepunctata differ between each other and from all other investigated species of S. (Schizophoria); the latter are indistinguishable on the sole basis of punctae characteristics.     

Les Toxorhynchites Theobald de Madagascar (Diptera: Culicidae)

L’analyse taxonomique de quelques dizaines d’adultes de Toxorhynchites provenant de Madagascar et appartenant à la collection de l’IRD (Centre de Montpellier), a montré que tous les spécimens faisaient partie du sous-genre Afrorhynchus Ribeiro, 1991 qui domine sur le continent africain. Ces Toxorhynchites de Madagascar présentent aussi les caractères du nouveau groupe Pauliani que nous décrivons. Ils constituent un ensemble d’espèces jumelles dont la morphologie externe est très homogène. En utilisant quelques nouveaux caractères présents sur les genitalia mâles ainsi que des diagrammes de dispersion, nous avons mis en évidence cinq espèces nouvelles qui viennent s’ajouter à Tx. (Afr.) pauliani (Doucet, 1951). Il s’agit de: Tx. (Afr.) madagascarensis n. sp., Tx. (Afr.) brunhesi n. sp., Tx. (Afr.) grjebinei n. sp., Tx. (Afr.) fontenillei n. sp. et Tx. (Afr.) lemuriae n. sp. Des clés d’identification des mâles, des femelles, des larves et des nymphes sont proposées. En conclusion, nous avançons quelques considérations théoriques concernant la systématique et l’évolution des Toxorhynchites.     

Metazoan parasites of Neogobius fishes in the Slovak section of the River Danube

Metazoan parasites were investigated in three non‐native fishes (monkey goby Neogobius fluviatilis, bighead goby Neogobius kessleri and round goby Neogobius melanostomus) collected from the former and current main channel of the River Danube and from the River Hron, Slovakia, in November 2003. Thirteen parasite species were identified: Triaenophorus crassus, Diplostomum sp., Tylodelphys clavata, Metorchis xanthosomus, Nicolla skrjabini, Gyrodactylus proterorhini, Pomphorhynchus laevis, Contracoecum sp., Raphidascaris acus, Anguillicola crassus, Unio tumidus, Anodonta anatina and Pseudoanodonta complanata. The maximum parasite diversity was found in N. fluviatilis. Total parasite abundance was significantly higher in N. kessleri, but no significant differences among sampling sites were observed. Pomphorhynchus laevis and glochidia of Anodonta anatina reached 100% prevalence in N. kessleri in the new channel of the Danube and, in general, these species were also the most prevalent parasites in all three goby species. For endoparasites, gobies served mostly as intermediate (digenean, cestodes and nematodes) or paratenic (acantocephalan and nematodes) hosts. All parasite species found are common parasites in the Middle Danube basin. No parasites specific to Neogobius, known from their native populations, were observed.     

Polystomatidae (Monogenea) of African Anura: Polystoma dawiekoki n. sp. parasitic in Ptychadena anchietae (Bocage)

Polystoma dawiekoki n. sp. is described as a new species of the Polystomatidae parasitic in the urinary bladder of the plain grass frog Ptychadena anchietae. This parasite was collected at Mkuze town and Mkuze Game Reserve in northern Kwazulu-Natal Province, in the Kruger National Park in Mpumalanga Province, South Africa, and at Bulwa in Tanga Province, East Usambara Mountains, Tanzania. It is distinguished from other African Polystoma species by a combination of characters, including the body size, size and shape of marginal hooklets and the haptor length to body length ratio. The presence of adult, as well as subadult, parasites in the same individuals, as is known for Eupolystoma, represents a significant evolutionary departure from the pattern of transmission typical of Polystoma in most of the other anuran hosts.     

Larval parasites ofOulema melanopus in Europe and their colonization in the United States

The cereal leaf beetle,Oulema melanopus (L.), of minor economic importance in Europe, was found in Michigan, USA, in 1959, and has caused increasing damage to small grains. Studies in Europe prompted the introduction into the United States, of 3 hymenopterous parasites of the larval stage:Tetrastichus julis (Walker),Diaparsis carinifer (Thomson), andLemophagus curtus Townes, as a multiplespecies biological control attempt. From 1964 to 1970, field collections in 10 European countries showed that parasitism averaged 12.3% byD. carinifer, 10.4% byT. julis, and 5.6% byL. curtus. Parasites are discussed with respect to life-history, distribution, constancy, hostrange, synchrony with host, and effects of encapsulation by the host larva. Techniques are described for parasite collection, rearing, shipment, overwintering in quarantine, field release, and recovery. Adult parasite releases in the USA (1964–1971) totaled 43,054D. carinifer, 31,123T. julis, and 3,109L. curtus. BothD. carinifer andT. julis are known to be established at several sites in Michigan, andT. julis is also established in Ohio.Lemophagus curtus was recovered in Michigan in 1972.     

Heterotrophic carbon gain by the root hemiparasites, Rhinanthus minor and Euphrasia rostkoviana (Orobanchaceae)

Hemiparasitic plants gain virtually all mineral nutrients and water from their host plant whilst organic carbon is provided, at least in part, by their own photosynthetic activity, although their rates of assimilation are substantially lower than that found in non-parasitic plants. Hence, hemiparasites must gain at least some of their organic carbon heterotrophically from the host plant. Despite this, heterotrophic carbon gain by root hemiparasites has been investigated only for a few genera. We investigated heterotrophic carbon gain by two root hemiparasites, Rhinanthus minor L. and Euphrasia rostkoviana Hayne (Orobanchaceae), using natural abundance stable isotope (δ¹³C) profiles of both parasites attached to C₃ (wheat) and C₄ (maize) hosts coupled to a linear two-source isotope-mixing model to estimate the percentage of carbon in the parasite that was derived from the host. Both R. minor and E. rostkoviana attached to maize hosts were significantly more enriched in ¹³C than those attached to wheat hosts with R. minor becoming more enriched in ¹³C than E. rostkoviana. The natural abundance ¹³C profiles of both parasites were not significantly different from their wheat hosts, but were less enriched in ¹³C than maize hosts. Using a linear two-source isotope-mixing model, we estimated that R. minor and E. rostkoviana adult plants derive c. 50 and 25% of their carbon from their hosts, respectively. In light of these results, we hypothesise that repeatedly observed negative effect of competition for light on hemiparasites acts predominantly in early ontogenetic stages when parasites grow unattached or the abstraction of host nutrients is less effective.     

Trypanoxyuris croizati n.sp. andT. callicebi Hugot & Vaucher, 1985 (Nematoda: Oxyuridae), two vicariant forms parasitic inCallicebus spp. (Primatia,Cebidae)

Trypanoxyuris croizati n. sp., a parasite ofCallicebus torquatus from Venezuela, is described. The following characters differentiate the new species from the nearest species,Trypanoxyuris callicebi Hugot & Vaucher, 1985 fromCallicebus moloch in Paraguay: inT. callicebi, (i) the hexagonal feature of the cephalic outline is less marked; (ii) crests forming the lateral alae are more developed; (iii) the body is less than half as wide; (iv) the oesophagus is much shorter and the oesophageal bulb less voluminous; (v) the excretory pore and the vulva are closer to the anterior extremity; (vi) the tail is much longer; and (vii) the eggs are more voluminous and their major axis is more elongate.T. callicebi andT. croizati n. sp. are considered to be vicariant forms, stemming from the same species when two populations and their respective hosts were isolated by a geographical barrier, the Amazon. The distribution of these two parasites, which closely matches the zoogeography of hosts, reinforces the hypothesis of Cameron (1929) who postulated a strict co-evolution of primates and their oxyurid parasites.

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Résumé Trypanoxyuris croizati n. sp., parasite d'unCallicebus torquatus du Venezuela, est décrite. La nouvelle espèce diffère de l'espèce la plus proche,T. callicebi Hugot & Vaucher, 1985, décrite chez unCallicebus moloch du Paraguay, pour les caractères suivants: chezT. callicebi, (i) la forme hexagonale du contours céphalique est moins marquée; (ii) les crêtes constituant les ailes latérales sont plus développées; (iii) la largeur du corps est inférieure presque de moitié, (iv) l'oesophage est relativement beaucoup plus court et le bulbe oesophagien moins volumineux; (v) le pore excréteur et la vulve sont plus rapprochés de l'apex; (vi) la queue est beaucoup plus longue; (vii) les oeufs sont plus volumineux et leur grand axe est plus allongé.T. callicebi etT. croizati n. sp. sont interprétées comme des formes vicariantes, issues d'une même espèce parasites dont deux populations, et leurs hôtes respectifs, se sont trouvés isolés par un obstacle géographique, le cours de l'Amazone. La répartition de ces parasites, qui souligne de façon étroite la zoogéographie de hôtes, renforce l'hypothèse de Cameron (1929), qui supposait l'existence d'un phénomène d'étroite co-évolution entre les Primates et leurs oxyures.

     

Some remarks on parasitic infections of the invasive Neogobius spp. (Pisces) in the Hungarian reaches of the Danube River, with a description of Goussia szekelyi sp. n. (Apicomplexa: Eimeriidae)

During a survey of the parasite fauna Neogobius spp., which only recently invaded Hungarian reaches of the Danube River upstream from Budapest, it was found that Neogobius melanostomus and N. fluviatilis had become common species. Neogobius kessleri was less frequent and the previously widespread Proterorhinus marmoratus was drastically reduced. The parasite fauna of the newcomer fish species was characterized by ubiquitous parasites of a wide host range, such as the trematode Nicolla skrjabini, the metacercariae of Metagonimus yokogawai and Apatemon cobitidis, the larval stages of the acanthocephalan Pomphorhynchus laevis and the nematode Rhaphidascaris acus, the glochidia of an Anodonta sp. (Mollusca) and the ciliophoran Ichthyophthirius multifiliis. The specific parasites of Neogobius spp. were represented by three intestinal coccidia: Eimeria daviesae, Goussia kessleri, and a new species described here as Goussia szekelyi sp. n. This survey showed that the rapid invasion of Ponto‐Caspian gobies in the northern Danube caused important changes in the fish fauna composition of the Danube River and enriched the parasite fauna of Hungarian fishes.     

A molecular and ecological study of Grillotia (Cestoda: Trypanorhyncha) larval infection in small to mid‐sized benthonic sharks in the Gulf of Naples,Mediterranean Sea

AimTrypanorhyncha cestodes comprise a wide range of heteroxenous parasites infecting elasmobranchs as definitive hosts. Limited data exist on the larval infection of these cestodes and the role of intermediate and paratenic hosts in the life cycle of these parasites. We investigated the factors that determine the occurrence and the level of infection of Grillotia plerocerci in the skeletal muscles of various benthonic sharks and analyzed the parasites through an integrative taxonomic approach.LocationMediterranean Sea.MethodsSharks obtained as bycatch of commercial trawling activities (i.e., Etmopterus spinax, Galeus melastomus, and Scyliorhinus canicula) were used in this study. Data from a limited number of Dalatias licha and Scyliorhinus stellaris were also included. Grillotia plerocerci were molecularly characterized using the partial 28S large subunit rDNA. Boosted regression trees were used to model the relationship between the abundance of infection with both morphological and physiological predictors in each host.ResultsPlerocerci of Grillotia were detected in all shark species except S. stellaris. Host species significantly differed in terms of parasite abundance, with the highest and lowest prevalence and abundance of infection detected in G. melastomus and E. spinax, respectively. The relative influence of the traits involved in explaining the parasite abundance was related to the host size in G. melastomus, while both morphology‐ and physiology‐related traits explained the patterns observed in E. spinax and S. canicula. The 28S rDNA sequences shared an identity of ∼99.40% with a Grillotia species previously found in the Mediterranean Sea. At intraspecific level, two different genotypes were found. A first type was retrieved only from D. licha, whereas a second type was found in G. melastomus, E. spinax, and S. canicula.Main conclusionsPresent results suggest that the two genotypes could be involved in different consumer‐resource systems and confirm most of the examined shark species as transport hosts of Grillotia species for unknown larger top predators.     

A PHYLOGENETIC STUDY OF PARASITIC GENERA PLACED IN THE FAMILY CHOREOCOLACACEAE (RHODOPHYTA)1

Red algal parasites are common and have a unique type of development in which parasite nuclei are transferred to host cells and “control” host cell development. Previous phylogenetic studies have concentrated on parasites closely related to their hosts, termed adelphoparasites. A second set of parasites, usually classified in a different family or tribe from their host, termed alloparasites, have not been studied phylogenetically. This study concentrates on the wholly parasitic family, the Choreocolacaceae (Gigartinales). Using small subunit rDNA sequence data, we found that all the parasites studied are within the same family as their host. Our data support the placement of Holmsella, species of which parasitize Gracilaria and Gracilariopsis, in the order Gracilariales and suggest that Holmsella is an old parasitic genus. Most other species of the Choreocolacaceae parasitize species of the Rhodomelaceae. The one exception is the hyperparasitism between Harveyella mirabilis (Reinsch) F. Schmitz et Reinke (Rhodomelaceae) and the parasite Gonimophyllum skottsbergii Setchell (Delesseriaceae). The parasites Bostrychiocolax australis Zuccarello et West and Dawsoniocolax bostrychiae (Joly et Yamaguishi‐Tomita) Joly et Yamaguishi‐Tomita are placed within the tribe Bostrychiae as are their hosts. Harveyella mirabilis has a single origin and has switched hosts several times during its passage between the Atlantic and Pacific Oceans. Evidence does not support the continued recognition of the family Choreocolacaceae. Our results also indicate that the distinction between adelphoparasites and alloparasites is unwarranted, with a continuum between newly evolved parasites closely related to their hosts and parasites less closely related to their hosts.