Dual pollination of Cretaceous Erdtmanithecales by thrips and beetles

Abstract Insect pollination represents one of the most consequential mutualisms in terrestrial ecosystems, yet its early evolutionary history remains poorly understood. The mid-Cretaceous, a period characterized by the rapid radiation of angiosperms, reshaped pollination networks, as insects either shifted from gymnosperm hosts to angiosperms or evolved in close association with them. Here, we report the first male of Pelretes bicolor (Kateretidae) from mid-Cretaceous Myanmar amber (∼99 Ma), preserved alongside three thrips (Thysanoptera). The beetle has enlarged mandibles and distinctive pronotal morphology, providing direct evidence of sexual dimorphism in this extinct lineage. The associated thrips, assignable to Parallelothrips (Stenurothripidae), carry Eucommiidites-type pollen, diagnostic of Erdtmanithecales, an enigmatic group of Mesozoic gymnosperms. This represents direct evidence of thrips pollination of Erdtmanithecales and establishes stenurothripid thrips as a generalist pollinator lineage in the Cretaceous. Reexamination of pollen associated with Pelretes vivificus, another Myanmar kateretid, indicates that these grains also correspond to the Eucommiidites type. Collectively, our study not only documents sexual dimorphism in fossil Kateretidae but also provides fossil evidence that both beetles and thrips were integral components of complex Cretaceous pollination networks during the rise of angiosperms. These findings highlight the versatility of early pollinators and shed light on the dynamics of insect–plant interactions during a critical interval in terrestrial ecosystem evolution.