Amphora tucumana sp. nov., is described from botton sediments of the Laguna Nostra (Cumbres Calchaquíes, 4300 m altitude, Tucumán province, Argentina). Its valvar structure is described, using LM and SEM. The principal characteristics of this species are its transapical costa-like internal thickenings, the raphe-legde covered by small and irregular depressions, and areolae of irregular length. Its relationships is discussed.