Environmental impacts identified near the localities of the seasonal killifishes in the Mid-Northeastern Caatinga ecoregion, northeastern Brazil. (A) Sand removal along the Cruxati river near locality 3 of Hypsolebias martinsi in Mundaú river basin, Itapipoca municipality in Ceará State; (B) silting in temporary pond (locality 14), and (C) construction of a real estate development near locality 15 of Cynolebias microphthalmus and H. antenori in Apodi-Mossoró river basin, Mossoró municipality in Rio Grande do Norte State.