Estudo morfológico de três espécies de Copépodes ergasilídeos (cyclopoida) parasitos de peixes actinopterígios no Brasil

Abstract

Copepoda Milne Edwards, 1840 harbors more than 14.000 species that show a high adaptative capacity, which reflects a rich morphological diversity in its representatives. Within parasitic copepods, the family Ergasilidae Burmeister, 1835 stands out as the most specious, being one of the common groups of parasitic crustaceans found in fish from Brazil. Despite this richness, some authors claim that the diversity and distribution of parasitic copepods in Brazil are underestimated, since only a small part of local ichthyofauna has been studied pertaining these organisms. Therefore, in the first chapter, two new species of ergasilid copepods of the genus Acusicola Cressey, 1970, i.e., A. iamarinoi Couto, Pereira, Luque, Paschoal & Pereira, 2022 and A. pasternakae Couto, Pereira, Luque, Paschoal & Pereira, 2022, are described based on specimens found infesting the gills of Lobotes surinamensis (Bloch, 1790) (Acanthuriformes: Lobotidae) off the coast of Pará, and Centropomus ensiferus Poey, 1860 (Carangaria incertae sedis: Centropomidae) off Sepetiba Bay, Rio de Janeiro, Brazil, respectively. This study represents the first report of a representative of Acusicola infesting fish from Lobotidae and Centropomidae, as well as expand the geographical distribution of the genus. In the second chapter, Ergasilus n. sp. is described based on individuals found on the gills of Sternopygus macrurus (Bloch & Schneider, 1801) (Gymnotiformes: Sternopygidae), in the Viana lagoon complex, Maranhão, Brazil. This ergasilid has a morphological pattern that differs from all congeners, including a lyre-shaped ornamentation on the ventral surface of first pediger somite, feature that have never been reported in the family before. The high morphological heterogeneity of Ergasilus von Nordmann, 1832 and its parafiletic status highlights the need for further revision on the genus in order to confirm its validity. This work also represents the first report of a parasitic copepod parasitizing S. macrurus, as well as the first time that an ergasilid is recorded infesting a representative of the family Sternopygidae.