BACKGROUND: Recent molecular studies have discovered substantial unrecognised diversity within the genus Diplostomum in fish populations in Europe and North America including three species complexes. However, data from the first intermediate host populations are virtually lacking. This study addresses the application of an integrative taxonomic approach to the cryptic species diversity of Diplostomum spp. in natural lymnaeid snail populations in Europe with a focus on the 'D. mergi' species complex. METHODS: Totals of 1,909 Radix auricularia, 349 Radix peregra, 668 Stagnicola palustris and 245 Lymnaea stagnalis were sampled at five reservoirs of the Ruhr river system in Germany and screened for infections with Diplostomum spp. Cercariae were examined and identified alive, fixed and under scanning electron microscopy. Sequences from the barcode region of the cytochrome c oxidase subunit 1 (cox1) mitochondrial gene and from the internal transcribed spacer cluster (ITS1-5.8S-ITS2) of the rRNA gene were amplified for 51 and 13 isolates, respectively. RESULTS: Detailed morphological and molecular analyses provided evidence for three named species (Diplostomum spathaceum, D. pseudospathaceum and D. parviventosum), and a further four species-level lineages ('D. mergi Lineages 2-4' and 'Diplostomum sp. Clade Q' in the lymnaeid snail populations from the Ruhr river basin. The paper provides the first descriptions of molecularly identified cercariae of D. spathaceum and of the cercariae of D. parviventosum, three lineages of the 'D. mergi' species complex and of 'Diplostomum sp. Clade Q'. CONCLUSION: The integration of molecular and morphological evidence for Diplostomum spp. achieved in this study will serve as a baseline for species identification of these important parasites of snail and fish populations and thus advance further studies on the distribution of Diplostomum spp. in Europe.

• MeSH
• biodiverzita MeSH
• fylogeneze MeSH
• hlemýždi klasifikace   parazitologie   MeSH
• infekce červy třídy Trematoda parazitologie   veterinární   MeSH
• molekulární sekvence - údaje MeSH
• nemoci ryb parazitologie   MeSH
• ryby klasifikace   parazitologie   MeSH
• Trematoda klasifikace   genetika   izolace a purifikace   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Německo MeSH
• Severní Amerika MeSH

Frequent infections with Diplostomum spp. (Digenea: Diplostomidae) were found in the freshwater snail Radix peregra (Müller) and three fish species, the salmonids Salmo trutta fario L., Salvelinus alpinus (L.) and the gasterosteid Gasterosteus aculeatus L., collected in four lakes in south-western Iceland in 2012. Detailed analysis of the isolates integrating molecular, morphological and ecological data revealed that these belong to Diplostomum spathaceum (Rudolphi, 1819) and five putative new species (three infecting both snails and fish). This paper provides detailed descriptions of the metacercariae of the six species-level lineages of Diplostomum spp. and of the cercariae of three of the lineages discovered in Iceland with comments on the application of ITS1 rDNA for species distinction within Diplostomum von Nordmann, 1832 in the light of the novel data. We strongly suggest the use of molecular evidence based on cox1 gene sequences (in addition to ITS1-5.8S-ITS2 sequences) in association with detailed assessment of the morphology of the larval stages in future studies of Diplostomum spp. in fish and snails.

• MeSH
• cerkárie anatomie a histologie   MeSH
• druhová specificita MeSH
• fylogeneze * MeSH
• hlemýždi parazitologie   MeSH
• jezera MeSH
• larva anatomie a histologie   MeSH
• Salmonidae parazitologie   MeSH
• Trematoda anatomie a histologie   klasifikace   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Island MeSH