Format: ORAL

Julia Gravendyck1,2, Franois-Nicolas Krencker1, Rute Coimbra3, Ulrich Heimhofer1

1 Institute of Geology, Leibniz University Hannover, Hannover, Germany 2 Bonn Institute for Organismic Biology, University of Bonn, Bonn, Germany 3 Department of Geoscience, University of Aveiro, Aveiro, Portugal

The timing of the origin of angiosperms is a long-standing topic of debate in plant evolution. Different disciplines and approaches provide highly variable age estimates. It is generally accepted, that early macro- and mesofossils showing unequivocal angiosperm features occur in lower Aptian deposits. Workers employing palynology, i.e., the extremely durable, abundant, and widespread pollen record, have suggested much earlier, but highly disputed ages. To date, it remains questionable how far back pollen with unequivocally angiospermous features can push back the age for the origin of (early) angiosperms. Here we present new early records from pre-Aptian coastal marine strata from the Lusitanian Basin of Portugal that are known for their rich and unique fossil assemblages and excellent pollen preservation. Based on strontium isotope stratigraphy, we provide a refined high-resolution stratigraphic framework for existing and newly studied sections to better constrain the age assignment of our new palynological findings of subsequent palynological findings. Employing a new fluorescence-based screening method paired with the standard light-microscope approach, we try to find the needle in the haystack. We document challenges and solutions to finding the extremely rare angiosperm pollen and illustrate new finds of early angiosperms with super-resolution microscopy (Airy Scan). The rare but exciting finds of four triaperturate pollen grains from the Early Barremian (124.63126.24 Ma, GTS2020) of Portugal indicate the presence of eudicot angiosperms in pre-Aptian strata and provide a new, well-dated calibration point for phylogenetic approaches.