The freshwater ichthyofauna in North and Central America is particularly diverse with high rates of endemism. Yet, the knowledge on their ectoparasitic flatworms is still limited and their richness is so far underestimated and may considerably increase with further study efforts. Thus, the proposed topic will specifically focus on ectoparasitic monogeneans with the aim to reveal the hidden diversity of this parasite group in largely diversified hosts belonging to distinct teleost fish families of the Nearctic region. Monogenean specimens were collected and fixed during the field expeditions in the USA, Canada, and Mexico. The student will first perform literature research and summarize the knowledge on host-parasite associations mainly focusing on monogeneans of the targeted fish representatives. Next, the student will focus on the morphology of monogeneans by measuring and drawing the haptoral and reproductive sclerotized parts of the flattened worms. Genetic data of monogenean communities will be further obtained in order to investigate the phylogenetic and evolutionary relationships among parasite fauna and their relatives worldwide.