Can host-specific monogeneans shed new light into evolutionary history of peri-Mediterranean cyprinids?
|Fakulta / Pracoviště MU|
|Popis||Cyprinidae are considered as one of the largest freshwater fish family in the world. In the western palearctic ecozone dual distribution pattern of cyprinid species is observed. While in the northern and central regions the cyprinid fauna is relatively uniform, comprising only low number of species with wide distribution range, in the southern parts of the region the number of endemic species is extremely high. The southern European Peninsulas are the most interesting regions inhabited by majority of cyprinid species from western Palearctic area. For example, Balkan freshwater fish fauna includes 59% of all European cyprinid species. In the Europe, cyprinids harbour different monogenean parasites such as diplozoids (e.g. Diplozoon, Eudiplozoon and Paradiplozoon), gyrodactylids (Gyrodactylus) or dactylogyrids (Dactylogryus). The most remarkable is the latter one, species rich genus of gill parasites, exhibiting narrow host specificity and high degree of morphological adaptation for their respective hosts. It is hypothesized that each cyprinid species can be parasitized by its own Dactylogyrus species and even within the single host they are specialized on the specific microhabitat. Due to the high host specificity we can also expect that the evolutionary history of Dactylogyrus is intimately linked to the speciation and historical dispersion of the cyprinids. Therefore, by study of this remarkable parasitic group we can shed new light on the evolutionary history of the cyprinids. From 2014 to 2018 we collected Dactylogyrus parasites from 127 endemic cyprinid species in 9 peri-Mediterranean countries – Albania, Algeria, Bosnia and Herzegovina, Croatia, Greece, Italy, Morocco, Portugal and Spain. In total, we identified representatives of 81 Dactylogyrus species from which 25 are potentially new for science. The phylogenetic reconstructions based on sequences of 18S and 28S rDNA combined with ITS1 region suggest multiple origin of Dactylogyrus in the Balkans and also in Iberian Peninsula. In the Balkans the results outlined the recent contact between endemic cyprinids and species with wide distribution range. In regards to Iberian Peninsula, our results revealed that endemic cyprinids are parasitized by Dactylogyrus species originating from two separated colonization events. According to the cophylogenetic analyses, there is a significant coevolutionary signal between phylogenies of endemic peri-Mediterranean cyprinids and Dactylogyrus. The most significant coevolutionary signal was detected between species belonging to tribus Barbini and their respective Dactylogyrus species. Our findings suggest that host-switch played an important role in the evolutionary history of Dactylogyrus parasitizing Balkan and Apennine cyprinids. Moreover, we showed that genetic structure and geographic distribution of these host-specific parasites are strongly influenced by recent introduction of the non-native cyprinid species into peri-Mediterranean area. Preliminary analysis based on molecular data also implies that several supposedly generalist species are in fact complexes of the cryptic species and therefore, the endemic Dactylogyrus fauna is probably far more diverse than was expected.|