Narciso, Rodrigo Bravin [UNESP]Brandão, HelenoPerbiche-Neves, Gilmarda Silva, Reinaldo José [UNESP]2020-12-122020-12-122020-06-01Acta Parasitologica, v. 65, n. 2, p. 327-334, 2020.1896-18511230-2821http://hdl.handle.net/11449/198433Purpose: To describe a new species of a parasitic copepod, Rhinergasilus digitus n. sp. (Cyclopoida, Ergasilidae), collected from the gills of the red-tailed lambari Astyanax fasciatus (Characiformes, Characidae) in two tributaries of the Jurumirim Reservoir (Upper Paranapanema River), São Paulo State, Brazil: Ribeirão dos Veados and Paranapanema River. Methods: Fish were collected using multi-panel gills nets. The gill of each fish was washed and examined in a stereo microscope for copepods. The copepods found were stored in 70% ethanol, cleared in lactic acid, and mounted in Hoyer’s medium. Drawings were made with the aid of a Leica microscope DMLS equipped with a drawing tube. Results: The new species differs from its congeneric species, Rhinergasilus piranhus (type-species), in having comparatively biggest body size (body length: 535–598 µm in the new species vs. 237–282 µm in R. piranhus); second antennary segment armed with a minute sensillum near middle of inner margin and a row of spinules on outer margin; third exopodal segment of leg 1 with digitiform process; interpodal plates two and three both ornamented with spinules along posterior margin; leg 5 reduced and represented by two unequal setae. Conclusions: Based on the morphological differences described above, we erected a new species of Rhinergasilus. Rhinergasilus digitus n. sp. is the second ergasilid described from A. fasciatus, as well as it represents the first report of this genus in a characid fish.327-334engCrustaceaCyclopoidaEctoparasiteJurumirimParanapanemaRibeirão dos veadosArtigo10.2478/s11686-020-00168-42-s2.0-85078308632