A. brunneus may refer to: Abacetus brunneus, a ground beetle Abraeus brunneus, a synonym of Parepierus brunneus, a clown beetle Acanthiophilus brunneus, a fruit fly found in Africa Aderpas brunneus, a longhorn beetle Agabus brunneus, the brown diving beetle, found in England Agniohammus brunneus, a longhorn beetle found in Borneo Allobates brunneus, the Chupada rocket frog, an amphibian found in South America Ameiurus brunneus, the snail bullhead, a freshwater fish found in the United States Amiurus brunneus, a synonym of Ameiurus brunneus Andricus brunneus, the clustered gall wasp, found in North America Anolis brunneus, a lizard found in the Bahamas Apristurus brunneus, the brown catshark, found in the Pacific Ocean Aspergillus brunneus, a fungus Ataxia brunneus, a synonym of Ataxia brunnea, a longhorn beetle found in the United States Attagenus brunneus, a carpet beetle found in North America and Europe