A. ambiguus may refer to: Abacetus ambiguus, a West African ground beetle Acinopus ambiguus, a ground beetle Acromyrmex ambiguus, a South American ant Agabus ambiguus, a North American diving beetle Amphientulus ambiguus, an Australian proturan Angomonas ambiguus, a parasitic protist Anochetus ambiguus, a prehistoric ant Ara ambiguus, the great green macaw, a Central and South American parrot Aspergillus ambiguus, a fungus Aster ambiguus, a synonym of Eurybia macrophylla, a North American plant Atrypanius ambiguus, a South American longhorn beetle