Abstract Monogeneans are a diverse group of flatworms, being ectoparasites of marine and freshwater fish, with great morphological and ecological variety. Analyzes of monogenetics in fish with great habitat diversity such as snappers are scarce in the literature, which already emphasizes the need for an update in this regard. The presente study found, morphologically characterized and mapped the geographic distribution and in known hosts the species Microcotyloides incisa and Microcotyloides impudicus, describing the first occurrence of these monogeneans for South America and in new hosts. The survey of hosts in the literature shows that M. incisa seems to have a greater Affinity with congener species of Lutjanidae and fish from other families, which may indicate a preference or specificity for fish of this family because they are congeners of their host type. The introduction of these parasites into South American waters may have occurred due to the migratory behavior of snappers, which are well distributed along the Mexican coast, where the parasites are usually reported. Here, we also bring the first occurrence of M. incisa for Lutjanus analis and Lutjanus jocu and M. impudicus for Ocyurus chrysurus and Lutjanus synagris, helping in the mapping and distribution of these monogenetic species in the Americas. flatworms variety regard found M families type coast reported Here synagris Americas

Abstract: Lutjanids are marine fish and commonly inhabit coral reefs, which have migratory habits and feed in a general way, due to these characteristics, are susceptible to infections by parasites, such as cuculanid nematodes. This work aimed to report for the first time, the occurrence of Dichelyne (Dichelyne) bonacii in Brazil, in two new hosts, Lutjanus analis and Rhomboplites aurorubens, acquired from local artisanal fishermen at the Aracaju city public fishing terminal (10 ° 54’17 “S37 ° 2’56” W), northeast coast of Brazil. Adult nematodes were collected from the intestinal tract of the hosts, clarified in Aman’s Lactophenol and were briefly described here. Three adult males and five gravid females were found, indicating that the two species of fish acted as definitive hosts. Currently, this species of parasite has been reported only from fish collected in the coast of Mexico, which makes this work the first record of this parasite in Brazilian coastal waters. The results show that probably the range of hosts and the distribution of D. (Dichelyne) bonacii is not as restricted as data pointed in the literature, being a little wider, extending also to waters that bathe the Brazilian coast.

ABSTRACT Parasites are important components of communities and constitute great part of the biological diversity found in ecosystems, providing valuable information about their hosts and the environment in which they live. However, despite its importance, parasitic diversity is still not well known in some regions of Brazil, especially with respect to fish parasites in the Northeast Region. The present study aims to perform the survey of gill parasites of fish from two tropical estuaries located in northeastern Brazil: Paraíba and Mamanguape rivers. Two collections were made in each estuary, one during the dry period (November / 2013) and the other during the rainy season (July / 2014). The fish were caught using a beach seine net, dragged along the main channel margin. After the identification, biometry and necropsy of the fish, their parasites were collected, stored and identified. For each species of parasite, the values of prevalence, mean intensity and mean abundance were calculated. Of the 882 examined fish, belonging to four species, 145 were parasitized by at least one species of parasite. In total, 18 taxa of parasites of the groups Monogenea, Digenea, Nematoda, Copepoda and Isopoda were recorded, being the copepod Acusicola brasiliensis the most abundant species of parasite.