Description of three new species of Eigenmannia (Gymnotiformes: Sternopygidae) from the rio Mearim and rio Parnaiba basins, Northeastern Brazil

Three new species of Eigenmannia belonging to the E. trilineata species-group are described. The first species is described from rio Mearim basin and can be diagnosed by lateral line stripe restricted to last two thirds of body, superior midlateral stripe present, 176-205 anal-fin rays, 10-15 scales rows above lateral line, 109-125 lateral line scales, 19-23 premaxillary teeth, 20-29 dentary teeth, 6-10 endopterygoid teeth, and 13-14 precaudal vertebrae. The second species is described from upper rio Parnaiba, and can be diagnosed by lateral line stripe restricted to last two-thirds of body, ii,11-13 pectoral-fin rays, 180-196 anal-fin rays, 12-15 scales rows above lateral line, 10-14 premaxillary teeth, 15-21 dentary teeth, 8-10 endopterygoid teeth, and 14 precaudal vertebrae. The third species is widespread in rio Parnaiba basin, and can be diagnosed by absence of lateral line stripe, absence of superior midlateral stripe, 182-228 anal-fin rays, 12-15 scales rows above lateral line, 107-131 lateral line scales, 32-34 premaxillary teeth, 35-44 dentary teeth, 9-12 endopterygoid teeth, and 13 precaudal vertebrae. A dichotomous key and the conservation status for the three species are provided.