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1.
Phylogenetic relationships between Bothriocephalus species from freshwater and marine teleosts from different geographical regions were studied using internal transcribed spacer-2 and partial 18S ribosomal DNA. The analyses revealed a paraphyly of Bothriocephalus with respect to the genera Polyonchobothrium, Anantrum, and Clestobothrium. The freshwater species Bothriocephalus claviceps, B. acheilognathi, and Bothriocephalus sp. from Dorosoma petenense formed a well-supported monophyletic cluster, with Polyonchobothrium at its base. In contrast, the type species, B. scorpii, clustered within a distinct lineage formed by a heterogeneous assemblage of marine species, Clestobothrium crassiceps and Anantrum tortum, and the freshwater species B. cf. japonicus. This shows that the current morphology-based classification is unlikely to reflect the phylogenetic relationships within this group and will require a thorough revision.  相似文献   

2.
The paper presents a systematic survey of some cestodes parasitizing freshwater fish in Italy. The following eight species were recorded: Monobothrium wageneri, Cyathocephalus truncatus, Triaenophorus nodulosus (plerocercoids and adults), Bothriocephalus acheilognathi, B. claviceps, Ligula intestinalis (plerocercoids), Schistocephalus sp. (plerocercoids) and Proteocephalus percae from Perca fluviatilis which is reported from freshwater fish in Italy for the first time. All the tapeworms recovered are described and figured.  相似文献   

3.
One hundred extended growth walleye fingerlings, Sander vitreus (Percidae), collected on 6 October 2004, from 1 rearing pond at the Lake Mills State Fish Hatchery in Lake Mills, Wisconsin, were examined for parasites. Diplostomum sp. (Trematoda: Diplostomatidae), Contracaecum sp. (Nematoda: Anisakidae), Bothriocephalus cuspidatus (Cestoda: Bothriocephalidae), and Proteocephalus sp. (Cestoda: Proteocephalidae) were the only parasites found. The first 3 species occurred as larval stages. Diplostomum sp. and Contracaecum sp. had similar prevalences, mean intensities, and mean abundances (72%, 2.2, and 1.6 and 71%, 2.1, 1.5, respectively) in walleye fingerlings. A headlamp technique used by the Wisconsin Department of Natural Resources personnel generated a prevalence of Diplostomum sp. in the lens that overestimated the prevalence of Diplostomum sp. found in a random subsample of 100 fingerlings examined with a microscope. Proteocephalus sp. and B. cuspidatus infected 14 and 12 fingerlings, respectively.  相似文献   

4.
Morphological identification of fish taxa can sometimes prove difficult because phenotypic variation is either being affected by environmental factors, phenotypic characters are highly conserved or marker selection has been inappropriate. DNA based markers especially neutral mitochondrial DNA (mtDNA) have been used widely in recent times to provide better resolution of systematic relationships among vertebrate taxa. The Asian Arowana (Scleropages formosus) is a high value ornamental fish belonging to the family Osteoglossidae with a number of different colour variants distributed geographically across different locations around Southeast Asia. Systematic relationships among colour variants still remain unresolved. Partial sequences of the Cytochrome B (Cyt B) and DNA barcoding gene, Cytochrome C Oxidase I (COI) were used here to assess genetic relationships among colour variants and as a tool for molecular identification for differentiating among colour variants in this species. Results of the study show that in general, colour pattern shows no relationship with extent of COI or Cyt B mtDNA differentiation and so cannot be used to identify taxa. Partial sequences of the mtDNA genes were sufficient however, to identify S. formosus from a closely related species within the order Osteoglossidae.  相似文献   

5.
Tribe Condamineeae appears to be well supported in recent phylogenetic studies. However, the species of Bathysa were divided into two clades, leading to restoration of Schizocalyx. We studied the reproductive biology of one species from each clade, which occur sympatrically in the montane Brazilian Atlantic forest. Flowering overlap was short (from December to March in B. australis and from February to June in S. cuspidatus). The flowers of both species are protogynous and homostylous and last for about 3 days. The unit of pollination in B. australis is the inflorescence. Its flowers have a greenish hypocrateriform corolla (tube about 5 mm long) and were mainly pollinated by bees and wasps in search of nectar. Schizocalyx cuspidatus has white flowers with an infundibuliform corolla (tube about 8 mm long), and its main pollinators were stingless bees in search of pollen. The pollination systems of the two species did not correspond to their pollination syndromes. Morphological differences between Bathysa and Schizocalyx were reflected in their pollination systems, with greater phenotypic specialization in S. cuspidatus, the flowers of which offer pollen as the main resource, an unusual feature within Rubiaceae. Schizocalyx cuspidatus showed higher reproductive capacity by having more inflorescences per plant, more ovules per flower, and twice the proportion of flowering individuals. However, the reproductive efficiency (fruit set, seed/ovule ratio) did not differ between the species, despite the higher frequency of visits by pollinators to S. cuspidatus. Self-compatibility in B. australis and self-incompatibility in S. cuspidatus seem to explain these results.  相似文献   

6.
Component communities of perch (Perca fluviatilis L) in Eurasia and the North American yellow perch (Perca flavescens Mitchill) were examined to determine the nature of their parasite communities. The scale of this investigation is continental and includes data collected across the distribution of each host species. Data were compiled from the literature and from 5 sample sites in North America. Four parasite species were found to occur frequently in the helminth component communities of P. flavescens. The cestodes Bothriocephalus cuspidatus and Proteocephalus pearsei, the digenean Crepidostomum cooperi, and the nematode Dichelyne cotylophora comprised a suite of species of which some or all occurred in most samples. Similarly, a group of 4 predictable parasite species was identified for P. fluviatilis in Eurasia, the digenean Bunodera luciopercae, the nematode Camallanus lacustris, the cestode Proteocephalus percae, and the acanthocephalan Acanthocephalus lucii. Specificity was not a requirement for predictability. Despite geographical isolation for millions of years, and different fish species interactions within and between continents, the predictability of these parasite assemblages indicates they are shaped by a biology, especially feeding patterns, common to both perch species. This is evidence that parasite assemblages comprised of nonhost-specific parasites in freshwater fishes are not merely stochastic assemblages but have key components that are predictable at this broad continental scale.  相似文献   

7.
Cortinarius is one of the most species-rich genera of mushroom-forming fungi. Based on phylogenetic and morphological evidence, Cortinarius, sect. Riederi, is introduced at sectional level (= subsect. Riederi sensu Brandrud & Melot). The taxonomy, phylogeny, ecology and distribution of not only mainly European but also including some North American taxa of this section are treated, which includes nine species and two varieties. Of these, three taxa are described as new (C. burlinghamiae, C. pallidoriederi and C. argenteolilacinus var. dovrensis). The sect. Riederi species possess morphological features similar to Phlegmacium group(s) and forms a phylogenetically isolated lineage, with no supported affinity to other phlegmacioid groups. Three taxa are known from both Europe and North America, two species are known only from North America and five only from Europe. Altogether, eight of the ten taxa are associated with conifers or northern (boreal-subalpine) deciduous trees (Betula spp.). Only two species occur in more temperate forests (Fagus forests), and no species have so far been found in thermophilous Quercus forests  相似文献   

8.
The North Pacific Ocean has been of great significance to understanding biogeography and speciation in temperate faunas, including for two species of char (Salmonidae: Salvelinus) whose evolutionary relationship has been controversial. We examined the morphology and genetics (microsatellite and mitochondrial DNA) of Arctic char (Salvelinus alpinus) and Dolly Varden char (Salvelinus malma) in lake systems in western Alaska, the eastern and western Arctic, and south of the Alaskan Peninsula. Morphologically, each lake system contained two forms: one (Arctic char) largely confined to lake habitats and characterized by greater numbers of pyloric caeca, gill rakers, and shallower bodies, and another (Dolly Varden) predominated in adjacent stream habitats and was characterized by fewer pyloric caeca, gill rakers, and deeper bodies. MtDNA partial (550 bp) d-loop sequences of both taxa were interspersed with each other within a single 'Bering' clade and demographic inferences suggested historical gene flow from Dolly Varden to Arctic char had occurred. By contrast, the taxa were strongly differentiated in sympatry across nine microsatellite loci in both lakes. Our data show that the two taxa are highly genetically distinct in sympatry, supporting their status as valid biological species, despite occasional hybridization. The interaction between these species highlights the importance of the North Pacific, and Beringia in particular, as an evolutionary wellspring of biodiversity.  相似文献   

9.
Forty-three taxa of Synurophyceae were identified by means of transmission electron microscopy of samples from ten different localities in southeastern Louisiana, USA, on the southern portion of the Atlantic Coastal Plain Province of North America. Samples were collected during a one month period when water temperatures ranged from 15.5–24.5"C. Sample pH values ranged from 4.4–7.2. Notable scale morphology variation was described for some taxa. The flora included three warm water taxa but was dominated by temperate and cosmopolitan taxa. Mallomonas prora and Synura australiensis are reported for the first time from North America. Comparisons with related studies from New World subtropical regions in Florida, USA, and Argentina were made, and significant North American range expansions were noted. The large number of aquatic habitats, 7–8 consecutive months at temperatures (6–20°C) best suited for development of synurophycean populations, and proximity to major bird migrations routes are postulated as explanations for the large number of reported species.  相似文献   

10.
Four species of Balansia (clavicipitaceous systemic grass pathogens) isolated from pastures where cattle showed signs of ergot toxicity were grown in culture. Balansia epichlo?, one isolate of B. claviceps, B. henningsiana and two isolates of B. strangulans produced conidia in submerged culture during the first stage of a two-stage fermentation procedure. When tranferred to a glucose/sorbitol/inorganic salts medium during the second stage, these four species produced ergot alkaloids in stationary cultures. The transfer of fungi cultured in the first medium to the second medium was necessary for alkaloid biosynthesis. One isolate of B. claviceps did not produce alkaloids. Balansia epichlo? produced chanoclavine (I), agroclavine, penniclavine, elymoclavine, ergonovine and ergonovinine. Balansia claviceps produced chanoclavine (I), ergonovine and ergonovinine. This is the first report of isolating ergonovine and ergonovinine, two lysergic acid derivatives, from fungi outside the genus Claviceps. Only chanoclavine (I) was identified from extracts of B. strangulans and B. henningsiana. Chanoclavine (I) and ergonovine were identified from smut grass (Sporobolus poiretii) parasitized by B. epichlo?, indicating that this endophyte produces alkaloids both in vivo and in vitro.  相似文献   

11.
Several European species of the terrestrial slug genus Arion have been introduced into North America. A case in point is the species complex A. subfuscus s.l. which has become one of the most abundant slug taxa in North America. In Europe this complex consists of at least two cryptic species, viz. A. fuscus and A. subfuscus s.s., the latter of which is further subdivided in five strongly divergent mtDNA lineages (A. subfuscus S1–S5). In order to determine which of these A. subfsucus s.l. taxa are present in the NE USA and in order to assess their population genetic structure, we compared mtDNA, nDNA and allozyme variation between populations from the NE USA and Europe. Our results show that (1) at least A. subfuscus S1 has become successfully established in the NE USA, (2) founder effects are the most likely explanation for the loss of a large amount of molecular genetic variation in populations from the NE USA (i.e. a loss of 96% of the 16S rDNA haplotypes, 67% of the ITS1 alleles and 46% of the alleles at polymorphic allozyme loci), and (3) part of the remaining genetic variation in NE USA populations was probably due to multiple introductions from the British Isles and the European mainland, and the hybrid structure of most of these source populations. Apparently, the extreme loss of molecular genetic variation in this introduced species has not prevented it from successfully establishing and spreading in novel environments.  相似文献   

12.
Senecio pauciflorus and S. indecorus (= Packera pauciflora and P. indecora ) are autogamous, high polyploid species with similar geographic ranges in North America. Their east-west distribution pattern including a disjunction in California is unusual within the aureoid Senecio complex and may provide insights into the origins of the aureoid complex. Taxonomic treatment of the two taxa has varied in the past due to the similarity and variability of the taxa. Results of morphological analyses of 192 herbarium specimens show that the taxa are best treated as two distinct species and that infraspecifìc variation is not related to geographical distribution. Separation of taxa remains difficult. California specimens are the most difficult to classify and may represent the ancestral group. Based on morphology and chromosome number it is suggested that the 5. pauciflorus-S. indecorus group may have originated from the arctic-alpine aureoid group including S. cymbalaria .  相似文献   

13.
Freshwater gomphonemoid diatom phylogeny: preliminary results   总被引:1,自引:0,他引:1  
Kociolek  J.P.  Stoermer  E.F. 《Hydrobiologia》1993,(1):31-38
A cladistic analysis of eleven freshwater gomphonemoid diatom taxa yielded three equally most parsimonious cladograms. The three cladograms suggest Gomphoneis Cleve is non-monophyletic as originally and recently circumscribed. Gomphoneis elegans and G. transsilvanica (Pant.) Krammer are more closely related to Gomphopleura Reichelt ex Tempère than to other members of the genus. Gomphoneis geitleri Kociolek & Stoermer appears to represent a monotypic lineage. Among the taxa with differentiated apical pore fields Gomphonema kaznakowi Mereschkowsky appears to be primitively astigmate.The three cladograms vary with regard to systematic affinities among the Gomphoneis herculeana (Ehrenberg) Cleve group, Miocene gomphonemoid species from Idaho (USA), gomphonemoid taxa from East Africa and Gomphonema sensu stricto. Despite variability in number of puncta rows per stria and presence of an axial plate in the Miocene species from North America, inclusion of these taxa in the analysis provided better resolution of relationships than if they were excluded.  相似文献   

14.
In 2003, the parasite fauna of 197 European eels Anguilla anguilla, captured at three different locations (Laufenburg, Karlsruhe and Beneeden Leeuwen) in the River Rhine, was analysed. The eels harboured a total of 18 species, among them the protozoa (Myxidium giardi, Myxobolus kotlani and Trypanosoma granulosum), acanthocephalans (Acanthocephalus anguillae, Acanthocephalus lucii, Echinorhynchus truttae, Pomphorhynchus laevis), nematodes (Paraquimperia tenerrima, Pseudocapillaria tomentosa, Camallanus lacustris, Raphidascaris acus, Spinitectus inermis and Anguillicola crassus), cestodes (Bothriocephalus claviceps and Proteocephalus macrocephalus) and monogeneans (Pseudodactylogyrus sp.). The parasite fauna at the different locations is discussed with respect to the crustacean fauna present at these locations. The investigation shows that changes in the composition of the crustacean fauna, due to the anthropogenic breakdown of a biogeographic barrier, are reflected in the composition of the intestinal eel parasite fauna.  相似文献   

15.
Members of the genus Clinostomum Leidy, 1856 are parasites that mature in birds, with occasional reports in humans. Because morphological characters for reliable discrimination of species are lacking, the number of species considered valid has varied by an order of magnitude. In this study, sequences from the DNA barcode region of cytochrome c oxidase I (CO1) and/or internal transcribed spacer (ITS) from specimens from Mexico, Bolivia, Peru, Brazil, Kenya, China and Thailand were analysed together with published sequences from Europe, Africa, Indonesia and North America. Although ITS and CO1 distances among specimens were strongly correlated, distance‐based analysis of each marker yielded different groups. Putative species indicated by CO1 distances were consistent with available morphological identifications, while those indicated by ITS conflicted with morphological identifications in three cases. There was little overlap in sequence variation within and between species, particularly for CO1. Although ITS and CO1 distances tended to increase in specimens that were further apart geographically, this did not impair distance‐based species delineation. Phylogenetic analysis suggests a deep division between clades of Clinostomum inhabiting the New World and Old World, which parallels the distribution of their principal definitive hosts, the Ardeidae.  相似文献   

16.
17.

With only six recognised genera, the family Clinostomidae Lühe, 1901 remains a global research interest of parasitologists and ecologists. Recent efforts have focused on providing molecular data to investigate species diversity, elucidate life-cycles, and make inferences on the group’s evolutionary history. Of the clinostomid genera, the monotypic Ithyoclinostomum Witenberg, 1926 has remained more enigmatic compared to the commonly encountered Clinostomum Leidy, 1856. Recent morphological and molecular evidence from metacercariae suggests a second Ithyoclinostomum species may exist in freshwater cichlids in Central America and Mexico. In a recent survey of great blue herons Ardea herodias L. from commercial catfish production farms in Mississippi, USA, two specimens of an abnormally large (> 20 mm) clinostomid were encountered in the oesophagus of a single bird. These specimens were identified as an Ithyoclinostomum sp. morphologically distinct from the only nominal species Ithyoclinostomum dimorphum (Diesing, 1850). Using morphological and molecular data these adult specimens were confirmed as conspecific with the larval metacercariae previously described from Central America and Mexico and represent the novel species, Ithyoclinostomum yamagutii n. sp.

  相似文献   

18.
A new species, Klasea yunus-emrei B. Dogan, Ocak & A. Duran (Asteraceae), is described from central Anatolia, Turkey. The species grows on calcareous soils in the Alpu district (Eski¸ehir province) in central Anatolia. It is morphologically similar to Klasea lasiocephala (Bornm.) Greuter & Wagenitz. Diagnostic morphological characters from closely similar taxa are discussed and arranged in a key. Ecology, conservation status and biogeography of the species are also presented. The achene surface of K. yunus-emrei and K. lasiocephala are examined by Scanning Electron Microscope. In addition, the geographical distribution of the new species and other related species are mapped.  相似文献   

19.
A new genus and three new species of Figitinae (Hymenoptera: Figitidae) are described from Colombia: Ferpereira Pujade-Villar n. gen., Ferpereira fiorellae Pujade-Villar n. sp., Neralsia levis Pujade-Villar & Petersen-Silva n. sp., and Figites colombiensis Pujade-Villar & Paretas-Martínez n. sp., which is the first species of Figites Latreille from Colombia and the second from South America. The diagnostic characters of these new taxa are illustrated.  相似文献   

20.
Megalonychidae are known from the Deseadan of Argentina and Bolivia to the present, represented by the tree sloth Choloepus Illiger. The principal fossil records of this clade are those from the Quaternary of Central America and the Antilles (e.g., Megalocnus Leidy, Acratocnus Anthony) and North America (e.g., Megalonyx Harlan, Pliometanastes Hirschfeld and Webb). From the Quaternary of South America, Megalonychidae are recorded in Peru (Diabolotherium Pujos, De Iuliis, Argot and Werdelin) and Brazil (e.g., Ahytherium Cartelle, De Iuliis and Pujos, Australonyx De Iuliis, Pujos and Cartelle). In Argentina they also have been recorded in the Santa Cruz Formation (early-middle Miocene) on the coast of Santa Cruz Province (Eucholaeops Ameghino), Arroyo Chasicó Formation (Protomegalonyx Kraglievich), Río Negro Formation, in the “conglomerado osífero” (ossiferous conglomerate) or “Mesopotamiense” (late Miocene) at the base of Ituzaingó Formation, Entre Ríos Province, and Pleistocene of Buenos Aires Province. Several authors have studied the Megalonychidae from the “conglomerado osífero”, but no systematic revision of the group has been undertaken beyond the original naming of species. Taking into account that a broad range of individual variation has been observed in the Megalonychidae from the Pleistocene of North America and the West Indies, and that a similar range probably existed among the megalonychids from the “conglomerado osífero”, then the number of valid species might be lower than previously proposed. Thus, the valid species recovered from the “conglomerado osífero” are Ortotherium laticurvatum Ameghino, Pliomorphus mutilatus Ameghino, Amphiocnus paranense Kraglievich, Protomegalonyx doellojuradoi Kraglievich, Pr. Praecursor Kraglievich, Megalonychops primigenius Kraglievich, and Paranabradys vucetichae Scillato-Yané. However, the establishment of synonymies, as well as the generic and specific assignation of the specimens is not an easy task, due to the peculiar taphonomical context of this stratigraphic unit.  相似文献   

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