Abstract: Bioluminescence in lampyroid clades represented one of the most distinctive behavioral traits among insects. Although the oldest-known bioluminescent lampyroid clade has recently been reported from the Cretaceous, the diversity and phylogenetic evolutionary history of early bioluminescent lampyroid clades remained unclear. Here, we documented the diversity of early bioluminescent lampyroid clades based on exceptionally well-preserved fossil specimens and further investigated their phylogenetic evolution. Our findings in this study: (1) support multiple independent origins of bioluminescence within the lampyroid clade; (2) present early ecological diversification in the extinct family Cretophengodidae; (3) advance our understanding of biological adaptations in the Cretaceous lampyroid clade; and (4) offer key insights into the evolutionary pathways underlying the origin and diversification of bioluminescence in insects.

Key words: Bioluminescence, Burmese amber, lampyroid clade, mid-Cretaceous, phylogenetics