Microcotylidae (Monogena) parasites of snappers (Perciformes: Lutjanidae) collected from the northeast coast of Brazil.

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.

First record of Dichelyne (Dichelyne) bonacii (Nematoda, Cucullanidae) parasitizing the intestine of two species of lutjanid fish (Perciformes, Lutjanidae) on the northeast Brazilian coast.

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.

Occurrence of Isopods in Two Species of Snappers (Lutjanidae) from Northeast Brazil.

Parasitic isopod species are poorly known in the northeastern coast of Brazil. In this sense, this study presents novel records of Isopoda of the families Aegidae, Cymothoidae, and Corallanidae. A total 69 specimens of Lutjanus analis and 19 of Lutjanus jocu, of which 46 isopods from 3 different species were collected, i.e. Rocinela signata, Cymothoa excisa, and Excorallana richardsoni. The species R. siganata and E. richardsoni are reported for the first time in L. jocu. A significant relationship between the parasite R. signata and the size of the fish L. jocu was also observed. The isopod C. excisa is considered an incidental finding in L. analis. To the authors' knowledge, this is the first report of this species in fish from Brazil. The three species of isopods are new occurrences in the State of Sergipe, northeast region of the country. An additional morphological characteristic observed in the dorsal setae of pleotelson in specimens of E. richardsoni was that one end of this structure wws bifid. This information contributes to the current body of knowledge of the morphology of this particular species.