Pollen evidence for Late Cretaceous differentiation of Proteaceae in southern polar forests

Abstract

Amongst diverse and abundant fossil proteaceous pollen in southeastern Australian Late Cretaceous (Campanian–Maastrichtian) sediments are forms identical with pollen of extant taxa within subfamilies Proteoideae, Persoonioideae, Carnarvonioideae, and Grevilleoideae. Taxa identified now have disparate geographic ranges within Australasia. Sclerophyllous Adenanthos and Stirlingia (Proteoideae) are restricted to the southern Australian Mediterranean climatic region; Persoonia (Persoonioideae) ranges into higher rainfall areas of eastern and northern Australia. Grevillea exul – Grevillea robusta and Telopea (Grevilleoideae) and Carnarvonia (Carnarvonioideae) occur in or fringe rain forests in eastern Australasia, as do other members (Macadamia, Gevuina–Hicksbeachia, Knightia, and Beauprea) reported previously. Pollen evidence thereby confirms evolution of both rain forest and sclerophyll members by the Campanian–Maastrichtian. Turnover of proteaceous pollen taxa near the Cretaceous–Tertiary boundary may reflect contemporaneous modifications to the proteaceous communities. Associated with the Late Cretaceous Proteaceae were diverse conifers (Microcachrys, Lagarostrobus, Podocarpus, Dacrydium, Dacrycarpus, and Araucariaceae), Nothofagus, Ilex, Gunnera, Ascarina, Winteraceae, Trimeniaceae, and probable Epacridaceae. The vegetation, which fringed a narrow estuary separating Antarctica from southern Australia, implies a mosaic of rain forest and sclerophyll communities but has no modern analogue. Key words: Proteaceae, Late Cretaceous, Australia, Antarctica.