Revisiting early angiosperm pollination: a reassessment of Angimordella beetle and co-occurring thrips from mid-Cretaceous amber

Background:
The Cretaceous rise of angiosperms profoundly reshaped terrestrial ecosystems, yet direct fossil evidence of early insect–angiosperm interactions remains scarce. Here, we re-examine a key mid-Cretaceous amber inclusion from Kachin, Myanmar, previously reported to preserve a pollen-bearing beetle (Angimordella burmitina) in close association with eudicot pollen.

Results:
Our reassessment supports the recent transfer of Angimordella from Mordellinae (crown-group Mordellidae) to Apotomourinae (stem-group Mordellidae), based on traits such as a short pygidium and the absence of a subapical metatibial ridge. This revised placement challenges earlier interpretations of Angimordella as a specialized angiosperm pollinator and instead suggests a more generalized or transitional ecological role. We also document a co-preserved thrips in direct contact with the pollen grains, representing the first fossil record of a thrips associated with angiosperm pollen.

Conclusions:
This fossil assemblage sheds light on the ecological complexity of mid-Cretaceous pollination systems, offering new insights into the incremental development of structured angiosperm–insect pollination networks.