Repeated and widespread evolution of biofluorescence in marine fishes

Biofluorescence, the absorption of high-energy light and its reemission at lower energy wavelengths, is widespread across vertebrate and invertebrate lineages, especially fishes. New observations over the past decade have significantly increased our understanding of the diversity and multifunctionality of fluorescence in fish lineages. In this study, we present a comprehensive account of all known biofluorescent teleosts and estimate the timing and frequency of the evolution of biofluorescence across this diverse group. We show that biofluorescence evolved numerous times in marine teleosts and is estimated to date back ~112 mya in Anguilliformes (true eels). Of the 459 known biofluorescent teleosts reported in this study, the majority are associated with coral reefs. We find that reef-associated species evolve biofluorescence at 10x the rate of non-reef species. Our results suggest that the chromatic and biotic conditions of coral reefs could have provided an ideal environment to facilitate the evolution and diversification of biofluorescence in teleost fishes.