title: Integrative taxonomy of European parasitic flatworms of the genus Metorchis Looss, 1899 (Trematoda: Opisthorchiidae).
abstract: Metorchis spp. are flukes (Platyhelminthes: Digenea) that infect vertebrates, including humans, dogs, cats, poultry and wild game, with cyprinid freshwater fish serving as typical second intermediate hosts. In their definitive hosts, the Metorchis spp. are difficult to identify to species. We provide and analyze sequences of two nuclear (18S rDNA and ITS2) and two mitochondrial (CO1 and ND1) DNA loci of four morphologically identified European species of the Metorchis, namely Metorchis albidus, Metorchis bilis, Metorchis crassiusculus and Metorchis xanthosomus, and of another opisthorchiid, Euamphimerus pancreaticus. DNA analysis suggests that the Metorchis specimens identified morphologically as M. albidus (from Lutra lutra), M. bilis (from Phalacrocorax carbo) and M. crassiusculus (from Aquila heliaca and Buteo rufinus) represent a single species. Thus, M. albidus (Braun, 1893) Loos, 1899 and M. crassiusculus (Rudolphi, 1809) Looss, 1899 are recognized as junior subjective synonyms of M. bilis (Braun, 1790) Odening, 1962. We also provide comparative measurements of the Central European Metorchis spp., and address their tissue specificity and prevalence based on the examination of extensive bird cohort from 1962 to 2015. M. bilis and M. xanthosomus can be morphologically diagnosed by measuring the extent of genitalia relative to body length and by the size ratio of their suckers. They also differ in their core definitive hosts, with ducks (Anas, Aythya) and coots (Fulica) hosting M. xanthosomus, and cormorants (Phalacrocorax), the birds of prey (Buteo, Aquila, etc.), piscivorous mammals (Lutra, Vulpes, Ursus, etc.) and humans hosting M. bilis. Previous reports on the Metorchis spp. contain numerous suspected misidentifications.
authors.affiliation: Comenius Museum, Moravian Ornithological Station, Přerov, Czech Republic.
authors.forename: Jiljí
authors.initials: J
authors.lastname: Sitko
authors.affiliation: Charles University in Prague, Third Faculty of Medicine, Prague, Czech Republic.
authors.forename: Jiří
authors.initials: J
authors.lastname: Bizos
authors.affiliation: Cardiff University, School of Biosciences, Cardiff, United Kingdom; Imperial College London, Department of Infectious Disease Epidemiology, London, United Kingdom.
authors.forename: Eleanor
authors.initials: E
authors.lastname: Sherrard-Smith
authors.affiliation: Cardiff University, School of Biosciences, Cardiff, United Kingdom.
authors.forename: David W G
authors.initials: DW
authors.lastname: Stanton
authors.affiliation: Slovak Academy of Sciences, Institute of Parasitology, Košice, Slovakia.
authors.forename: Petronela
authors.initials: P
authors.lastname: Komorová
authors.affiliation: Charles University in Prague, Third Faculty of Medicine, Prague, Czech Republic. Electronic address: petr.heneberg@lf3.cuni.cz.
authors.forename: Petr
authors.initials: P
authors.lastname: Heneberg
mesh_terms: D000818:Animals; D001717:Birds; D004275:DNA, Ribosomal / Q000235:genetics; D006801:Humans; D008322:Mammals; D009890:Opisthorchidae / Q000145:classification* / Q000166:cytology / Q000235:genetics / Q000302:isolation & purification; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D014201:Trematode Infections / Q000469:parasitology*
chemical_list: D004275:DNA, Ribosomal; D012337:RNA, Ribosomal, 18S
keywords: Bile duct; Cholangitis; Diarrhea; Liver; Platyhelminthes; Zoonosis