Cretophengodidae, a new Cretaceous beetle family, sheds light on the evolution of bioluminescence

• Published in: Proceedings of the Royal Society. B, Biological sciences Biological sciences, 2021-01, Vol.288 (1943), p.20202730-20202730
• Main Authors: Li, Yan-Da, Kundrata, Robin, Tihelka, Erik, Liu, Zhenhua, Huang, Diying, Cai, Chenyang
• Format: Article
• Language: English
• Subjects: Animals; Coleoptera - genetics; Fireflies; Fossils; Male; Myanmar; Palaeobiology; Phylogeny
• ISSN: 0962-8452; 1471-2954
• DOI: 10.1098/rspb.2020.2730

Bioluminescent beetles of the superfamily Elateroidea (fireflies, fire beetles, glow-worms) are the most speciose group of terrestrial light-producing animals. The evolution of bioluminescence in elateroids is associated with unusual morphological modifications, such as soft-bodiedness and neoteny, but the fragmentary nature of the fossil record discloses little about the origin of these adaptations. We report the discovery of a new bioluminescent elateroid beetle family from the mid-Cretaceous of northern Myanmar ( 99 Ma), Cretophengodidae fam. nov. gen. et sp. nov. belongs to the bioluminescent lampyroid clade, and would appear to represent a transitional fossil linking the soft-bodied Phengodidae + Rhagophthalmidae clade and hard-bodied elateroids. The fossil male possesses a light organ on the abdomen which presumably served a defensive function, documenting a Cretaceous radiation of bioluminescent beetles coinciding with the diversification of major insectivore groups such as frogs and stem-group birds. The discovery adds a key branch to the elateroid tree of life and sheds light on the evolution of soft-bodiedness and the historical biogeography of elateroid beetles.