Evolutionary history and fossilsEvolutionary history and fossils

Evolutionary history and fossils

The Wollemi Pine is of considerable significance in the study of the evolutionary relationships of early Gondwanan flora, and the species has contributed to the understanding of structures in fossil Araucariaceae (Macphail et al. 1995; Chambers et al. 1998; Dettmann & Jarzen 2000). Fossil evidence suggests that major gymnospermous (non-flowering) forests or woodland strata were once widespread in Australia, and Araucariaceae fossils from the Tertiary period have been found in every Australian state (Lange 1982). A decline in the distribution of Araucariaceae occurred in the late Quaternary, coinciding with increasing temperatures, dryness and incidence of fire (Kershaw and Wagstaff 2011). Understanding of the prehistoric distribution of the Wollemi Pine has previously been informed by the distribution of the fossil pollen Dilwynites, understood to be very similar to the pollen of Wollemi Pine. Dilwynites pollen has been identified in sediments from Australia, New Zealand, Antarctica, and Patagonia, from the late Cretaceous to the late Tertiary (Macphail et al. 1995; Chambers et al. 1998; Dettmann & Jarzen 2000; McLoughlin & Vajda 2005; Macphail et al. 2013). However, more recent analyses (Macphail & Carpenter 2014; Seyfullah et al. 2023) have demonstrated that Dilwynites pollen may represent other members of the Araucariaceae, in addition to Wollemi Pine, and that Wollemi Pine pollen is more variable than had previously been reported.