The Atlantic ghost crab, Ocypode quadrata, is a species of ghost crab, once described as an "occult, secretive alien from the ancient depths of the sea". It is a common species along the Atlantic coast of the United States, where it is the only species of ghost crab; its range of distribution extends from its northernmost reach on beaches in Westport, Massachusetts, south along the coasts of the tropical Western Atlantic Ocean to the beach of Barra do Chui, in Rio Grande do Sul in southern Brazil.