A new whipworm from arvicolid rodents, Trichuris arvicolae Feliu et al., 2000, in the helminth fauna of Poland

During the parasitological examination of wild rodents from the vicinity of Wroc?aw a single whipworm female was isolated from a field vole Microtus agrestis. The nematode was determined as Trichuris arvicolae. This is the first report of this parasite in Poland.     

New records of helminth species and their hosts in Poland

Information on species of parasitic helminths native to Poland is provided by the Pasozytnicze helminty Polski. Gatunki. Zywiciele. Bia?e Plamy. Until the middle of 2007, there were 1205 species of recorded helminths including 126 species of Monogenea, 338 of Trematoda (Digenea), 279 of Cestoda, 427 of Nematoda and 35 of Acanthocephala. They represented 32.9% of the species recorded in Europe (i.e., registered in the Fauna Europaea database). During the following three years up to the middle of 2010, 64 new species of Polish helminths were detected: 7 Monogenea, 15 Trematoda (Digenea), 21 Cestoda, 20 Nematoda and one Acanthocephala. Most hosts of the new helminth species were reported from birds (40 species), but also from fish (13 species) and mammals (10 species). Only one new species of helminth was detected in amphibians.     

Diversity of the parasite fauna of cyprinid (Cyprinidae) and percid (Percidae) fishes in the Vistula Lagoon, Poland

A total of 2398 fish specimens (1091 Percidae and 1307 Cyprinidae) belonging to 16 species (3 Percidae and 13 Cyprinidae), caught in the Polish part of the Vistula Lagoon were examined within December 1994-March 1997. The parasites found were identified as belonging to 63 taxa (61 species as well as Diplostomum spp. flukes and glochidia Unionidae gen. sp. which could not be identified to species) of the Microsporea (1), Protozoa (1), Myxozoa (2), Monogenea (10), Digenea (15), Cestoda (11), Nematoda (11), Acanthocephala (5), Hirudinea (1), Mollusca (1), Copepoda (4), and Branchiura (1). The percids and cyprinids were found to support 37 and 40 parasitic taxa, respectively, the taxon-richest parasite fauna occurring in zander, Sander lucioperca (26 taxa), followed by carp bream, Abramis brama (24), European perch, Perca fluviatilis (24), roach, Rutilus rutilus (19), ruffe, Gymnocephalus cernuus (15), and Prussian carp, Carassius gibelio (11). The remaining fish species hosted less than 10 parasitic species each. Metacercariae of the genus Diplostomumn, found in about 37% of the fish examined, and Tylodelphys clavata, recorded in about 24% of the fish, proved the commonest parasites. The study showed the Vistula Lagoon cyprinid and percid parasite fauna to be dominated by freshwater species, frequencies of their occurrence in the brackishwater lagoon being lower than those in freshwater reservoirs. Frequencies of the 6 marine parasitic species found in the lagoon were, too, lower than those in the sea. It is suggested that some of the parasites (Ancyrocephalus paradoxus, Diplozoon paradoxum of the Monogenea, Diplostomum spp., Tylodelphys clavata of the Digenea, and Achtheres percarum of the Copepoda) prefer brackishwater habitats.     

Genetic calibration of species diversity among North America's freshwater fishes

Freshwater ecosystems are being heavily exploited and degraded by human activities all over the world, including in North America, where fishes and fisheries are strongly affected. Despite centuries of taxonomic inquiry, problems inherent to species identification continue to hamper the conservation of North American freshwater fishes. Indeed, nearly 10% of species diversity is thought to remain undescribed. To provide an independent calibration of taxonomic uncertainty and to establish a more accessible molecular identification key for its application, we generated a standard reference library of mtDNA sequences (DNA barcodes) derived from expert-identified museum specimens for 752 North American freshwater fish species. This study demonstrates that 90% of known species can be delineated using barcodes. Moreover, it reveals numerous genetic discontinuities indicative of independently evolving lineages within described species, which points to the presence of morphologically cryptic diversity. From the 752 species analyzed, our survey flagged 138 named species that represent as many as 347 candidate species, which suggests a 28% increase in species diversity. In contrast, several species of parasitic and nonparasitic lampreys lack such discontinuity and may represent alternative life history strategies within single species. Therefore, it appears that the current North American freshwater fish taxonomy at the species level significantly conceals diversity in some groups, although artificially creating diversity in others. In addition to providing an easily accessible digital identification system, this study identifies 151 fish species for which taxonomic revision is required.     

Landscape dynamics and diversification of the megadiverse South American freshwater fish fauna

Landscape dynamics are widely thought to govern the tempo and mode of continental radiations, yet the effects of river network rearrangements on dispersal and lineage diversification remain poorly understood. We integrated an unprecedented occurrence dataset of 4,967 species with a newly compiled, time-calibrated phylogeny of South American freshwater fishes—the most species-rich continental vertebrate fauna on Earth—to track the evolutionary processes associated with hydrogeographic events over 100 Ma. Net lineage diversification was heterogeneous through time, across space, and among clades. Five abrupt shifts in net diversification rates occurred during the Paleogene and Miocene (between 30 and 7 Ma) in association with major landscape evolution events. Net diversification accelerated from the Miocene to the Recent (c. 20 to 0 Ma), with Western Amazonia having the highest rates of in situ diversification, which led to it being an important source of species dispersing to other regions. All regional biotic interchanges were associated with documented hydrogeographic events and the formation of biogeographic corridors, including the Early Miocene (c. 23 to 16 Ma) uplift of the Serra do Mar and Serra da Mantiqueira and the Late Miocene (c. 10 Ma) uplift of the Northern Andes and associated formation of the modern transcontinental Amazon River. The combination of high diversification rates and extensive biotic interchange associated with Western Amazonia yielded its extraordinary contemporary richness and phylogenetic endemism. Our results support the hypothesis that landscape dynamics, which shaped the history of drainage basin connections, strongly affected the assembly and diversification of basin-wide fish faunas.

Geological and climatic events are widely believed to shape the biodiversity of continental biotas (1–3), yet we are only beginning to understand the nuanced ways in which individual geological and climatic events have contributed to evolutionary diversification (speciation minus extinction) across large spatial scales (4–7). South America harbors the most diverse fauna of continental freshwater fishes in the world (~5,750 species), providing unique opportunities to study the effects of geological history and river dynamics on diversification in obligate aquatic taxa (8, 9). Hydrogeographic processes, operating over tens of millions of years, have caused predictable changes in the geometry of river drainage networks, by isolating and merging portions of adjacent river basins and their connections to the sea, and by altering the physiochemical characteristics of water discharge (10, 11). Here, we evaluate the influence of major geological events on diversity patterns of obligate freshwater fishes of South America over the past 100 Ma, the time period over which hydrogeographic events shaped the origins of modern fluvial systems (4, 5, 12). We conducted the most comprehensive assessment of diversification in this group to date, using an extensive dataset on species geographic occurrences and a newly compiled, species-dense phylogeny of South American freshwater fishes (13). This new synthesis afforded us the opportunity to link unique hydrogeographic events with the spatial and temporal diversification and dispersal of individual fish clades.The historical dynamics of South American river basins and aquatic biotas were strongly shaped by four prominent geophysical events (Fig. 1) (11, 14). The first was the final separation of South America from Africa during the Late Cretaceous (c. 100 Ma). Between the Late Cretaceous and Early Paleogene (c. 100 to 55 Ma), river drainage patterns of South America were controlled by the location of the preexisting continental uplands (cratons and shields), ongoing uplift of the Andean cordilleras, super greenhouse climatic conditions characterized by high temperatures and precipitation, and dramatically fluctuating eustatic sea levels. As a result, most low-elevation coastal plains and interior structural basins were covered by nearshore marine habitats, and upland freshwater riverine and riparian habitats were intermittently isolated and connected (4, 15). During the Paleogene (c. 55 to 33 Ma), the Proto-Amazon-Orinoco river basin (Proto-Amazon basin, hereafter) drained the Sub-Andean Foreland basin, including much of northern South America and the northern La Plata region (Fig. 1 A and B; 5, 16).Open in a separate windowFig. 1.Bioregions, principle current landforms and sub-basins, and approximate chronology and location of the principal landscape evolution events that shaped the current drainage basins of South America and influenced the diversification of freshwater fishes. (A) Current river basins and geological formations mentioned in the text and the six bioregions proposed (detailed in SI Appendix). (B–E) Between 100 and 55 Ma, aquatic systems in South America were intermittently connected by multiple marine transgressions and regressions.Thus drainages across the continent during this time were intermittently connected by epicontinental seaways. During this time, the Proto-Amazon basin was the main drainage of northern South America, flowing through the sub-Andean foreland. At the same time, the Paraná and Paraguay basins (La Plata bioregion) represented major aquatic systems in South America (4, 5, 10, 11). Additional information about principal landforms controlling basin connectivity at each time interval and for each bioregion delineation appears in SI Appendix, Table S1.Second, intraplate compression and tectonic subduction along the Pacific margin during the Oligocene (c. 33 to 23 Ma) drove tectonic uplift of the Altiplano and Michicola Arch (c. 30 Ma) associated with formation of the Bolivian Orocline (17). These orogenic deformations intermittently isolated and connected rivers among the Western Amazonian, Upper Madeira, and Upper Paraguay sedimentary basins of the Sub-Andean Foreland, facilitating vicariance and biotic exchanges across their watershed divides (Fig. 1C; 4, 18–20). Third, tectonic reactivation and uplift of Serra do Mar and Serra da Mantiqueira ranges in southeastern Brazil during the Early Miocene (c. 23 to 16 Ma) re-routed some rivers from the La Plata basin directly to the Atlantic (Fig. 1D; 21, 22–24), isolating many terrestrial and aquatic species in the coastal basins of the Atlantic Forest. Also, at about this time (c. 23 to 10 Ma), the Pebas Megawetland extended over large areas of the modern Western Amazonia and Orinoco basins (Fig. 1D; 5, 7, 22–26). Fourth, the uplift of the Northern Andes during the Late Miocene and Pliocene (c. 10 to 4.5 Ma), which profoundly reorganized regional river drainage networks, isolated the modern Amazon, Orinoco, Magdalena, and Maracaibo river basins and connected the modern Western and Eastern Amazon basins, thereby forming the modern transcontinental Amazon River (Fig. 1E; 16, 27).Variation in connectivity and configuration of regional river networks resulting from these four major geological events strongly shaped diversity patterns of the Neotropical freshwater fish fauna (4, 12). In particular, river capture, in which a river drainage system is diverted from its historic bed to a neighboring bed, is a landscape evolution process that exerts a potent influence on diversification in obligate freshwater organisms, because it both severs existing and constructs new corridors of aquatic habitat among portions of adjacent drainage basins (18, 28). Because continental fishes are eco-physiologically restricted to freshwater habitats within drainage basins, watersheds represent natural dispersal barriers, as evidenced by the strong spatial concordance of geographic ranges in freshwater fish species with basin boundaries (28, 29). By isolating and connecting populations of aquatic taxa across watershed divides, river capture exerts complex effects on the diversity of freshwater organisms, for example by elevating extinction risk through geographic-range contraction, promoting speciation by genetic isolation and vicariance, and increasing biotic homogenization by dispersal and gene flow (16, 30–32).Although the role of geological events in shaping the evolution of rivers and freshwater diversity has long been recognized, the relative contributions of particular geological events remain poorly understood. Insights into their contributions can be gained only by studying diversity patterns at appropriate spatial, temporal, and taxonomic scales (28, 33–36). For instance, recent studies identified Western Amazonia as the center of Amazon fish diversity (high species richness, low phylogenetic diversity (PD), and high phylogenetic clustering, compared to Eastern Amazonia), with younger fish lineages dispersing progressively eastward across Amazonia after the formation of the modern transcontinental river c. 10 Ma (37–39). However, this interpretation did not consider the more ancient history of Neotropical fishes in the upland Brazilian and Guianas Shields, the formation of the modern lowland (< 250 m.a.s.l.) fauna in the Proto-Amazon basin, and the phenotypically and taxonomically modern composition of all the known Miocene paleo-ichthyofaunas (4, 40). Taking this deeper history into account, Pliocene and Pleistocene events may have served more as buffers against extinction than as drivers of speciation in the formation of Amazonian fish species diversity (Fig. 2; 15, 41). In fact, the most species-rich clades of Neotropical freshwater fishes are thought to have radiated during the Paleogene (c. 63 to 23 Ma) (4, 42, 43).Open in a separate windowFig. 2.Changes in the rates of net lineage diversification among South American freshwater fishes. Tips represent 2,523 fish species. (A) Branch colors indicate net lineage diversification rate estimated by BAMM, where red indicates highest and blue lowest diversification rates. Significant shifts in diversification rates are shown as pale green circles on the branches. Selected representative clades of Melanorivulus, Orestias, Ancistrini, Hypostomus, and Corydoras species are illustrated. The principal orders are represented by colored columns to the right of the tree tips. The timescale at the bottom is expressed in millions of years ago (Ma). Vertical dashed lines indicate timing of the main principal hydrogeographic events detailed in the inset legend on the left. (B) Rates-through-time plots based on BAMM estimations, considering all bioregions together (see Material and Methods for parametrization details). The shaded areas around the curves correspond to 95% CIs of the estimated rates. Dashed lines indicate the time period when most of shifts in diversification rates were estimated. (C) Rates-through-time plots considering the species present in each bioregion separately. Rates of diversification, speciation, and extinction were estimated mainly within crown taxa. The five photographs: Wikipedia Commons. *Ancistrini species of genera Hopliancistrus, Guyanancistrus, Pseudolithoxus, Lasiancistrus, Pseudancistrus, Panaque, and Pterygoplichthys.In the case of South American freshwater fishes, previous macroevolutionary studies have been hindered by the large number of species (~5,750), remote sampling localities, and logistical difficulties of gathering reliable data (8). Our new data on fish distributions, which we combine with a new, time-calibrated molecular phylogeny, offer powerful resources to study the role of geomorphological events and associated river captures in shaping fish diversity over longer time periods and larger spatial scales than has previously been attempted. In particular, we evaluate the prediction that the high diversity in Western Amazonia was influenced by biogeographical bridges formed across different aquatic systems and time periods, which led to both accelerated diversification rates and a role for Western Amazonia as a principal source of freshwater fish species for all of South America.     

广西横县淡水鱼吸虫囊蚴感染情况调查

目的 了解广西横县野生鱼类吸虫囊蚴感染情况.方法 从横县旺天塘水库采集常见的小型野生鱼类,用肌肉压片法和消化法检测吸虫囊蚴,根据囊蚴形态、排泄囊结构和囊壁厚度等特征区分吸虫的种类.结果 检查490尾鱼,共查到4种鱼源性吸虫囊蚴,分别是华支睾吸虫、台湾棘带吸虫、棘隙吸虫和台湾次睾吸虫,感染率依次为43.88％、1.84％、1.84％和0.61％.华支睾吸虫囊蚴寄生于尾鳍基部的概率高于其他部位.结论 横县野生鱼类的鱼源性吸虫感染严重,其中华支睾吸虫感染率最高,鱼尾鳍基部寄生的囊蚴最多.     

Digenea species in chosen populations of freshwater snails in northern and central part of Poland

BACKGROUND: The aim of this work was to determine the biodiversity of digenean larvae in the snail populations from various water bodies. MATERIAL AND METHODS: Snails under study were collected from 29 reservoirs situated in northern and central part of Poland. During the period 1999-2005 10.581 snails from 6 species (among which two species dominated: Lymnaea stagnalis--9.469, and Planorbarius corneus--737 specimens) were examined for shedding cercariae. The total number of 4.404 molluscs was parasitized by 25 species of Digenea. The dominant species found were: Diplostomum pseudospathaceum (Diplostomidae), Echinoparyphium aconiatum (Echinostomatidae) Plagiorchis elegans and Opisthioglyphe ranae (Plagiorhiidae) in Lymnaeidae, while Rubenstrema exasperatum/Neoglyphe locellus (Omphalometridae) and Tylodelphys excavata (Diplostomatidae) in Planorbidae. The adults of the most of Digenea species found in snails were reported from birds.     

Parasymphylodora parasquamosa Kulakova, 1972 (Trematoda, Digenea)--new species of the parasite fauna of Poland

The present short note deals with atypical specimens of the digeneans, collected from fish Leuciscus idus caught in the Vistula mouth, and earlier described (Rokicki 1975) as Asymphylodora kubanicum (Issaitschikoff, 1923) Markewitsch, 1951. The reexamination of these specimens indicated that they represent the species Parasymphylodora parasquamosa Kulakova, 1972. This is a new digenean species in the parasitic fauna of Poland.     

Biological and ecological background of nematode fauna structure formation in the alimentary tracts of wild Anatinae ducks in north-western Poland

The study involved a total of 250 wild ducks representing 17 species of three ecologically different tribes: the Anatini (113 individuals), the Aythyini (71), and the Mergini (66). The ducks, obtained mainly from fishermen and hunters, were examined for the presence of parasites, using the generally accepted methods. Analyses of nematode assemblage structure were conducted with methods described in the literature. In addition, significance of differences in intensity of infestation was determined in relation to the hosts' age and sex as grouping variables. Significance of differences in infestation prevalence was tested with the Pearson Chi2 test or its modifications (V-square test, Chi2 test with Yates' correction, and the exact Fisher's test), while the Mann-Whitney U test was applied to infestation intensity and relative density. Similarity coefficients were ordered using the cluster analysis module of the STATISTICA 6.0 computer software; Ward's algorithm was used for grouping, Euclidean distance being applied as the similarity measure. The ducks examined were found to host a highly diverse nematode assemblage, consisting of a total of 22 species representing the following 7 families: Amidostomatidae, Anisakidae, Ascarididae, Tetrameridae, Acuariidae, Dioctophymatidae, and Capillariidae, the core of the assemblage being formed by the following 7 species: Amidostomoides acutum, A. monodon, A. petrovi, Tetrameres fissispina, Echinuria uncinata, Eucoleus contortus, and Capillaria anatis. The assemblage of parasitic nematodes in the ducks examined was found to be characterized by a high organ specificity, as the parasites selected mainly the gizzard and proventriculus as their microhabitats (10 and 8 typical species, respectively) and firmly avoided the duodenum and cloaca. Individual parasite species were observed to show a clear preference with respect to location in the host's alimentary tract, which means that, for a distinct majority of the parasitic species, typical sites could be identified. No significant effects of host's age and sex on nematode infestation parameters could be revealed, although - in certain species - those variables proved of a key importance for their specificity. The nematodes showing a distinct preference towards young birds include E. uncinata and Ingliseria cirrohamata, a still higher specificity being displayed by T fissispina and A. petrovi (selectively parasitising young females) and C. anatis (selective with respect to young males). The species which were more frequently recorded in the ducks aged two years and more, particularly in the adult males, include A. monodon and A. acutum. A clear relationship between the ecology of a host and the structure of its parasitic nematode assemblage was observed. Each of the tribes was distinct in the specific nematofauna of its members, each nematofauna possessing its own well-expressed core. The nematofauna of swimming ducks (Anatini) consisted of 11 species, the core being formed by A. acutum, E. uncinata, T fissispina, and E. contortus. The diving ducks (Aythyini) were found to host 8 nematode species, the core being formed by A. petrovi, T. fissispina, and C. anatis. The nematofauna of the predacious Mergini was found to consist of as many as 17 species, although one of them (A. monodon) was a distinct dominant. The nematode fauna of those birds showed also a relatively high proportion of T. fissispina, the most polyxenic nematode, recorded in 10 host species of all the tribes studied. Although the problem of habitat partitioning between various components of a nematode assemblage could not be unambiguously resolved, it was evident that cases of co-occurrence involved mainly co-invasions at different sections of the alimentary tract of the same host, the strongest relations being found for those species that formed the core of a nematode assemblage. Co-invasions affecting a host's organ concerned almost exclusively representatives of the families Amidostomatidae and Acuariidae in the gizzard and those of the Tetrameridae and Acuariidae in the proventriculus. The similarities between nematofaunas of the ducks studied are only weakly related to the systematic position of the respective ducks; much stronger relationships with ecological characteristics (mainly food type and feeding habits) were revealed. It seems that this is why the nematofauna of Common Goldeneye is much more similar to that of the Aythyini than to that of the Mergini to which the species is taxonomically assigned.     

Myxosporidians of freshwater fishes in Cameroon. I. New species of Myxidium Bütschli, 1882

This work deals with the study of myxosporidians parasitizing freshwater fishes in Cameroon. Fishes belonging to four families are concerned: Cyprinodontidae, Distichodontidae, Cyprinidae and Mormyridae. Five new species of Myxidium, all inhabiting the gall-bladder of their hosts, are described and named. They are as follows: Myxidium birgii, M. camerounensis, M. petrocephali, M. nyongensis and M. brienomyri. We have paid particular attention to vegetative stages in distinguishing species.