The rise of flowering plants in the high southern latitudes of Australia

Abstract

The Early Cretaceous high-paleolatitude palynofloras from the Otway and Gippsland basins of southeastern Australia contain diverse angiosperm assemblages not described previously. Clavatipollenites hughesii recovered from the early Aptian Upper Cyclosporites hughesii subzone in the Gippsland Basin represents the first record of angiosperm pollen in Australia, coeval to records recovered from the Great Artesian and North West Shelf basins of northern Australia. Tricolpate pollen including Tricolpites variabilis, Rousea georgensis and Striatopollis spp., are first recorded in the late Albian Upper Coptospora paradoxa subzone in southeastern Australia. This represents the second oldest occurrence of tricolpate pollen in Australia, the first occurring in the older middle Albian Lower Coptospora paradoxa subzone in the northern Great Artesian Basin. By the latest Albian Phimopollenites pannosus Zone angiosperms had diversified rapidly in southeastern Australia. The delayed appearance, rise in abundance and diversification of eudicot angiosperms in the high-latitude southern basins of Australia, relative to low- and mid-latitude settings, supports a latitudinally diachronous pattern of angiosperm range expansion from warmer paleoequatorial regions to relatively cooler high-latitude settings. Increasing mean annual temperatures globally in the late Albian likely facilitated the expansion of angiosperms into high-latitude settings in the Southern and Northern hemispheres.