Molecular prospecting for European Diplostomum (Digenea: Diplostomidae) reveals cryptic diversity

Diversity, specificity and speciation in larval Diplostomidae (Platyhelminthes: Digenea) in the eyes of freshwater fish, as revealed by DNA barcodes

“…First, the fidelity of sequenced metacercariae of Diplostomum spp. for either lens or non-lens tissues (e.g., Locke et al, 2010a;Georgieva et al, 2013;Blasco-Costa et al, 2014) supports the diagnostic utility of the infection site. Second, molecular phylogenetic analysis shows lens and non-lens species each form a clade of closely related Diplostomum spp.…”

“…Aside from their importance in fish health, eye-dwelling diplostomids are frequent subjects of evolutionary and ecological studies (e.g., Ballabeni and Ward, 1993;Kalbe and Kurtz, 2006). However, diplostomid metacercariae are difficult to identify morphologically and molecular methods are often used to distinguish species (Locke et al, 2010a,b;Rellstab et al, 2011;Cavaleiro et al, 2012;Behrmann-Godel, 2013;Chibwana et al, 2013;Désilets et al, 2013;Georgieva et al, 2013;Ndeda et al, 2013;Blasco-Costa et al, 2014;Pérez-del-Olmo et al, 2014;Kuhn et al, 2015;García-Varela et al, 2015;Mateos-Gonzalez et al, 2015;Otachi et al, 2015). Consequently, DNA sequences from diplostomids are accumulating from all over the world, particularly from Diplostomum spp.…”

“…Sequences can clarify whether morphological heterogeneity represents interspecific (BlascoCosta et al, 2014;Faltý nková et al, 2014;Pérez-del-Olmo et al, 2014) or intraspecific variation among metacercariae (Cavaleiro et al, 2012;Otachi et al, 2015). Molecular links to adults from avian definitive hosts are usually needed to identify, rather than merely discriminate, species of metacercariae (Galazzo et al, 2002;Locke et al, 2010aLocke et al, , 2011Georgieva et al, 2013;Pérez-delOlmo et al, 2014). However, even when sequences are obtained from adult diplostomids, often not all species detected in surveys of metacercariae are resolved (Galazzo et al, 2002;Georgieva et al, 2013;Pérez-del-Olmo et al, 2014).…”

“…Molecular links to adults from avian definitive hosts are usually needed to identify, rather than merely discriminate, species of metacercariae (Galazzo et al, 2002;Locke et al, 2010aLocke et al, , 2011Georgieva et al, 2013;Pérez-delOlmo et al, 2014). However, even when sequences are obtained from adult diplostomids, often not all species detected in surveys of metacercariae are resolved (Galazzo et al, 2002;Georgieva et al, 2013;Pérez-del-Olmo et al, 2014). The result is a sequence database dominated by unidentified, provisional species, many of which have been distinguished primarily through DNA sequence analysis.…”

“…Contrary to what Gibson (1996) expected based on the mobility and distribution of their avian hosts, none of the genetically distinguished Diplostomum spp. are common to both the Nearctic and Palearctic (Galazzo et al, 2002;Locke et al, 2010a;Cavaleiro et al, 2012;Georgieva et al, 2013). Intriguingly, it appears this biogeographic partition results mainly from two waves of Nearctic to Palearctic colonisation, one in the lens clade, the other in the clade of non-lens species (BlascoCosta et al, 2014).…”