First successful hybridization experiment between native European weatherfish (Misgurnus fossilis) and non-native Oriental weatherfish (M. anguillicaudatus) reveals no evidence for postzygotic barriers

The European weatherfish Misgurnus fossilis (Linnaeus, 1758) is a threatened freshwater species in large parts of Europe and might come under pressure from currently establishing exotic species. Additional threats arise if those hybridize which has been questioned previous research. Regarding the hybridization M. × anguillicaudatus (Cantor, 1842), we demonstrate that despite considerable genetic distance between parental species, estimated long divergence time different ploidy levels do not represent postzygotic barrier for Oriental weatherfish. paternal can be easily differentiated based on external pigment patterns with hybrids showing intermediate patterns. No difference standard metabolic rate, indicating lack hybrid vigour, renders predictions potential to difficult. Therefore, physiological basis invasiveness via remains elusive requires further existence prezygotic reproductive isolation mechanisms fertility F1 tested predict globally invasive