The beetle, known by its Latin name Cretophengodes, was found petrified in a piece of amber in northern Myanmar. The tropical location was teeming with insect life during the Cretaceous Period, said study author Chenyang Cai, an associate professor at the Nanjing Institute of Geology and Palaeontology at the Chinese Academy of Sciences in Beijing.
“We even have dinosaur remains data from the same amber deposit in which Cretophengodes was found,” said Cai.
Each of the insect’s antennae had 12 branching segments, but what caught Cai’s attention was the light organ nestled in its belly. That organ gave the beetle bioluminescence, the ability for a living organism to produce its own light, Cai said.
Modern insects such as fireflies and fireflies are part of Elateroidea, the same superfamily classification for animals from which the beetle comes.
Cretophengodes is one of the oldest bioluminescent beetles out there, so it gives researchers an insight into the early evolutionary building blocks of this superfamily.
It’s not known why the beetles were bioluminescent, but based on family members, Cai speculated that the function was used as a defense mechanism. Today, some young beetle larvae in the same superfamily have used light to protect themselves from predators, and adults are known to use their light abilities to attract mates.
Study author Erik Tihelka, a paleobiology student in the School of Earth Sciences at the University of Bristol in the United Kingdom, said he wants to spend time researching which predators caused the evolution of bioluminescence in Cretaceous beetles. His hypotheses include bird-like dinosaurs and graves of animals that fed on the forest floor.
“I find it fascinating that we owe the glow of fireflies to an old arms race with predators and prey with the dinosaurs,” said Tihelka.