The female of Ergasilus coatiarussp. n. (Copepoda, Poecilostomatoida, Ergasilidae) is described from the gills filaments of Cichla monoculusSpix, 1831 from the Amazon basin. The new species differs from the others known for the genus in having only one segment in the exopod of the 4th leg and one serrate spine at the union of the 3rd and 4th segments of the antenna.
Copepoda; Ergasilus coatiarus sp. n; Amazon; Fishes parasites