Abstract
BackgroundEuropean species of the large genus Phyllodistomum Braun, 1899 had historically been erected based solely on morphological characters. Unfortunately, many of them are still poorly known and inadequately described. Molecular approaches are critical to delineate species which were impossible to differentiate based on morphology alone.MethodsNew samples of adult Phyllodistomum spp. were collected from the urinary bladder and/or ureters of European freshwater fishes and fixed to conduct a light and scanning electron microscopy study, and to obtain sequences of nuclear (ITS2 spacer and 28S rRNA gene), to be analysed in the context of a molecular phylogeny.ResultsBased on new findings, a new species of Phyllodistomum from the urinary bladder of the European perch, Perca fluviatilis, in Volga River basin, Russia, is described. Additionally, new data on the morphology and tegumental surface topography of P. macrocotyle (Lühe, 1909) Odhner, 1911 from ureters of the common rudd, Scardinius erythrophthalmus, is presented. The host range of P. folium, confirmed by DNA analysis, is extended to other cyprinid fish species.ConclusionsThe present study has again shown that species of the genus Phyllodistomum are in dire need of revision based on both molecular analysis and detailed morphological redescriptions of the forms attributed to the genus. Morphologically, P. kupermani n. sp. most closely resembles P. pseudofolium, a highly host-specific parasite of Gymnocephalus cernuus (L.), but molecular phylogenetic analyses based on ITS2 and 28S rDNA sequences showed that these species are distantly related. Phyllodistomum kupermani n. sp. was found to be phylogenetically most closely related to the type-species of Phyllodistomum, P. folium. Phylogenetic analyses revealed that Phyllodistomum kupermani n. sp. and P. folium formed a clade with other freshwater species for which cystocercous cercariae develop in bivalves of the family Sphaeriidae. The micromorphology and tegumental surface topography of P. macrocotyle revealed in the present study provide a valuable taxonomic criterion for congeneric species differentiation.
Highlights
European species of the large genus Phyllodistomum Braun, 1899 had historically been erected based solely on morphological characters
P. kupermani n. sp. most closely resembles P. pseudofolium, a highly host-specific parasite of Gymnocephalus cernuus (L.), but molecular phylogenetic analyses based on internal transcribed spacer 2 region (ITS2) and 28S rDNA sequences showed that these species are distantly related
Phylogenetic analyses revealed that Phyllodistomum kupermani n. sp. and P. folium formed a clade with other freshwater species for which cystocercous cercariae develop in bivalves of the family Sphaeriidae
Summary
European species of the large genus Phyllodistomum Braun, 1899 had historically been erected based solely on morphological characters. To validate the independent taxonomic status of this genetic linage, a comparative morphological study of Phyllodistomum species from P. fluviatilis was required. Phyllodistomum trematodes found in D. polymorpha were referred to as P. folium sensu Sinitsin, 1905 or P. dogieli Pigulevsky, 1953 but recent molecular evidence has shown that P. macrocotyle is the only valid Phyllodistomum species far documented from D. polymorpha [5]. It should be noted that the study of Peribáñez et al [11] used comparative analysis of ITS1-5.8S-ITS2 sequence data in order to link digeneans (named as P. folium) from the urinary system of three cyprinid species, S. erythrophthalmus, Cyprinus carpio and R. rutilus, and the sporocysts found in zebra mussels, D. polymorpha, in the Ebro River, Spain. Adult digeneans were not observed by microscopic examination and no morphological characteristics of these specimens are available from this study
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
