Amber-encased fossil shines light on evolution of bioluminescent insects

Trapped in amber for ~100 million years, an exceptionally well-preserved, light-producing beetle sheds light on the diversification of bioluminescent beetles in the Cretaceous period and provides the missing fossil link between fireflies' living relatives.

source https://phys.org/news/2021-01-amber-encased-fossil-evolution-bioluminescent-insects.html