Beetle pollination of Erdtmanithecales, an extinct lineage of Mesozoic gymnosperms

The rise of flowering plants from the Late Cretaceous to early Palaeogene (approx. 100-50 Ma) triggered a macroecological transformation on land, propelling a sustained increase in biodiversity. While insect pollinators and herbivores played key roles in this shift, direct fossil evidence of insect pollination of gymnosperms remains scarce. Here, we report two exceedingly rare nitiduloid beetles (Coleoptera) in amber that bear dense coverings of Eucommiidites pollen, attributed to the extinct gymnosperm order Erdtmanithecales, providing direct evidence for insect pollination of extinct seed plants. The exceptional preservation in amber, combined with high-resolution morphological data derived from destructive (high-precision dissection) and non-destructive imaging (confocal laser scanning microscopy), enables unambiguous reconstruction of pollen transport and interactions between these beetles and their gymnosperm hosts. The co-occurrence of thrips (Thysanoptera) with similar pollen and associated pollen-laden coprolites suggests complex plant-insect interactions and convergent evolution of pollen-feeding behaviours. Together, these findings reveal a novel insect-mediated pollination mode that contributed to structuring the Mesozoic terrestrial biodiversity prior to the ecological dominance of flowering plants.