The first stage in the Oligocene epoch, preceded by the Priabonian (Late Eocene), followed by the Chattian, and dated at 33.9–28.4 Ma ago (Int. Commission on Stratigraphy, 2004). It is roughly contemporaneous with the lower Zemorrian (N. America), most of the Whaingaroan (New Zealand), and the upper Aldingan and lower Janjukian (Australia).