A. nigra

A. nigra may refer to:


 * Actia nigra, a tachinid fly species
 * Aculeola nigra, the hooktooth dogfish, a small, little known dogfish, the only member of the genus Aculeola
 * Alpinia nigra, an herb in the ginger family
 * Arkoola nigra, a fungus plant pathogen species
 * Astrapia nigra, the Arfak Astrapia, a large black bird of paradise species