Metazoan parasites of the Ocellated killifish, Floridichthys polyommus (Cyprinodontidae) in La Carbonera coastal lagoon, Yucatán, Mexico

The Ocellated killifish or “bolín yucateco”, Floridichthys polyommus, is an endemic resident of the Yucatan Peninsula, Mexico; it tolerates hypersaline and oligohaline conditions and is considered the dominant species in these ecosystems. In this study, we analyzed 108 individuals of F. polyommus between 2019 and 2013 from La Carbonera coastal lagoon, northern Yucatán Peninsula. We report the taxonomic composition of their metazoan parasite fauna at the infracommunity (individual hosts) and component community (whole sample) levels, estimating parasite community attributes such as species richness, abundance, and diversity. Fish individuals were measured, dissected, and examined for ecto and endoparasites. Metazoan parasites were identified using morphological and molecular data. Sixteen parasite taxa were found, including six digeneans, three nematodes, and one of the following: cestode, acanthocephalan, copepod, isopod, argulid, hirudinean, and pentastomid. Ten of them were found as larval stages. The prevalence and mean intensity of infection were calculated for each parasite taxon. The cestode Glossocercus caribaensis was the most prevalent taxon, whereas the digenean Ascocotyle sp.1 was the most abundant. For ecological analyses, three species of Contracaecum were lumped together. The species richness and diversity of the component community were 14 and 0.049, respectively, whereas at the infracommunity level, both parameters were 1.9 ± 1.27 and 0.147 ± 0.225. The parasite species richness values in F. polyommus at both levels were higher than those previously reported in other species of Cyprinodontidae. We discuss that the parasite community of F. polyommus reflect its importance in energy transport in coastal lagoons of the Yucatán Peninsula.