A true Luciolinae fossil from the mid-Cretaceous Burmese amber provides new insights into the early evolution of fireflies (Coleoptera: Lampyridae)-Supplementary material

In this study, we uncover a new fossil genus and species, Cretoluciolabirmana gen. et sp. nov., derived from a high-quality piece of the mid-Cretaceous Burmese amber. Unlike previous studies that mainly relied on comparative morphology, our work employs phylogenetic analytical approachesto determine the systematic placement of the fossil. By analyzing anintegrated dataset comprising410 morphological characters and eight AHE loci across 38 representative taxa, we demonstrate that this fossil is a true Luciolinaemember. This findingestablishes a minimum age constraint of 99 million years for Luciolinae, the crown group of Lampyridae. Our results challenge the current systematic placements of the other two previously described fossil genera within Luciolinae, Flammarionellaand Protoluciola, suggesting that the mid-Cretaceous Burmese fauna may have harbored greater firefly diversity than previously recognized. Furthermore, our study provides insights into the ecological traits of early fireflies, supporting the hypothesis that theywere nocturnal and employed various survival and courtship strategies, thereby enhancing our understanding of the evolution of Lampyridae.