Nothofagus cupules from Oligocene-Early Miocene sediments at Balfour, Northwest Tasmania, Australia

Abstract

The acceptable macrofossil record of Nothofagus (Nothofagaceae) is relatively sparse, with most published records represented by poorly preserved specimens. The Tasmanian fossil record is an exception to this, with an abundance of well-preserved Nothofagus remains. Oligocene-Early Miocene sediments near Mount Balfour in northwest Tasmania preserve cupules of five species of Nothofagus in three of the four extant subgenera. Subgenus Lophozonia is represented by Nothofagus glandularis, subgenus Nothofagus by Nothofagus bulbosa, and subgenus Brassospora by Nothofagus peduncularis and the new species Nothofagus balfourensis and Nothofagus robustus. Subgenus Lophozonia is still present in Tasmania, but subgenus Nothofagus is now restricted to South America and subgenus Brassospora to New Guinea and New Caledonia. These three subgenera have only been recorded together previously in the Early Oligocene in Tasmania. This record extends that combination, indicating a long and presumably stable ecological relationship among the species involved. Extinct climates are proposed as the most likely reason for the past co-occurrence of these subgenera and their current vast latitudinal and longitudinal separation.