A diverse and well-preserved Late Jurassic-earliest Cretaceous palynoflora - almost exclusively of spores and pollen grains - is described in this and the succeeding Part Two from four boreholes in the Eromanga Basin, southern Queensland. The stratigraphic sections studied, predominantly of continental (fluvio-lacustrine) origin, comprise the following lithostratigraphic units (ascending order): upper Adori Sandstone, Westbourne Formation (major focus of this study), and lower Hooray Sandstone. A total of 164 spore-pollen species have been identified in this investigation. Of these, the majority (102 species distributed among 40 genera) are detailed systematically in this initial Part One, and comprise trilete azonate spores, followed by part of the trilete zonate spore component. Three new spore species - Biretisporites vallatus, Osmundacidites verrucatus, and Apiculatisporis serratus - are established; and two new combinations are proposed, Convolutispora prisca (McKELLAR) and Trilites volkheimeri (FILATOFF). In the ensuing Part Two, the remainder of the systematic section (detailing the trilete-zonate, monolete, and hilate spores, the pollen grains, and incidental microphytoplankton cysts) will be presented, together with discussions of the biostratigraphic, palaeobotanical, and palaeoecological implications of the palynofloral assemblages.
