Diversity and Phylogenetic Relationships of European Species of Crepidostomum Braun, 1900 (Trematoda: Allocreadiidae) Based on rDNA, with Special Reference to Crepidostomum oschmarini Zhokhov & Pugacheva, 1998

Authors

Romualda Petkevičiūtė, Institute of Ecology and Nature Research Centre, Vilnius, Lithuania
Virmantas Stunžėnas, Intstitute of Ecology and Nature Research Centre, Vilnius, Lithuania
Alexander E. Zhokhov, Papanin Institute of Inland Waters, Russian Academy of Sciences
Larisa G. Poddubnaya, Papanin Institute of Inland Waters, Russian Academy of Sciences
Gražina Stanevičiūtė, Institute of Ecology and Nature Research Centre, Vilnius, Lithuania

Date of this Version

2018

Citation

Parasites & Vectors (2018) 11: 530, 17 pages

doi: 10.1186/s13071-018-3095-y

Also available at https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-018-3095-y

Comments

Copyright 2018, the authors. Open access material

License: Creative Commons Attribution 4.0 International (CC BY 4.0 International)

Abstract

Background

Within the genus Crepidostomum Braun, 1900, identification of species and taxonomic decisions made only on the basis of adult morphology have resulted in great problems associated with evaluating actual diversity and validity of species. Life cycle data, while equal in importance to adult characters, are scarce, controversial or incomplete for most Crepidostomum spp. In this study, rDNA sequences generated from adult and larval Crepidostomum spp. and some other allocreadiid species were analyzed to reveal the diversity and phylogenetic relationships of the species and their host range. Detailed morphological description based on light microscopy, SEM tegumental surface topography and genetic data are provided for the poorly known trematode C. oschmarini Zhokhov & Pugacheva, 1998 found in the intestine of two teleost fish species, Barbatula barbatula (L.) and Cottus gobio L.

Results

We characterized 27 isolates of adult and larval parasites. Based on newly obtained 28S and ITS1-5.8S-ITS2 rDNA sequences, new intermediate and final hosts were ascertained, and life cycles clarified for some allocreadiids. New knowledge on the diversity and phylogenetic relationships of European Crepidostomum spp. was gained. The validity of C. oschmarini was verified based on comparative sequence analysis. Ophthalmoxiphidiocercariae of C. oschmarini were recorded in sphaeriid bivalves Pisidium (Euglesa) casertanum (Poli). Additionally, morphological differences between gravid specimens of C. oschmarini and other related species were observed.

Conclusions

Species of the Allocreadiidae parasitizing fishes in Europe are distributed among two monophyletic genera, Allocreadium and Bunodera, and two paraphyletic Crepidostomum clades. A complex of Crepidostomum metoecus (syn. C. nemachilus), C. oschmarini and Crepidostomum sp. 2 clustered in one clade, and a complex of C. farionis, Crepidostomum sp. 1 and, probably, C. wikgreni in the other. Molecular data indicated that C. oschmarini and Crepidostomum sp. 2 presumably have a wide geographical distribution in Europe. The new data provided evidence that Crepidostomum is a more diverse genus than can be judged from morphological data and host switching in this genus may occur independently of fish-host phylogeny