Extensive past distributions for major gondwanic floral elements: macrofossil evidence

Abstract

The past geographical positions and climates of the high latitude Southern Hemisphere land masses (New Zealand and the southern parts of South America and Australia) are crucial to an understanding of plant evolution and migration in the region. A review of the macrofossil record reveals many examples of taxa which are present as fossils on one or two of these land masses but now occur elsewhere in the Southern Hemisphere. The main examples include Austrocedrus, Libocedrus (Cupressaceae), Araucaria sectionColumbea (Araucariaceae) and Nothofagus subgenera Nothofagus and Fuscaspora in Australia, Eucalyptus (Myrtaceae) and mn-Gymnostoma Casuarinaceae in New Zealand and probably South America, Araucaria section Intermedia in New Zealand and Akania (Akaniaceae) and Dacrycarpus (Podocarpaceae) in South America. The local extinction of these taxa is probably dae to a variety of factors, including climatic change, microsite changes due to the northward movement of land masses, and changes in the frequency of catastrophic disturbance.