A. antiquus may refer to: Abacetus antiquus, a ground beetle found in India, Myanmar, and Sri Lanka Adesmus antiquus, a synonym of Phoebemima antiqua, a longhorn beetle found in Brazil Anomalopteryx antiquus, a synonym of Anomalopteryx didiformis, the bush moa, an extinct flightless bird Astacus antiquus, a synonym of Protastacus antiquus, a prehistoric decapod