Britannica
Sources used in this answer
Where were some of the best-known fossil butterflies discovered?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
Lepidoptera
Heliconius butterfly in South America.
The best-known fossil butterflies were discovered in the shales of the Florissant Formation, a geological deposit located in Colorado. These fossils date back to the Eocene-Oligocene boundary, approximately 33.9 million years ago. Among these specimens are examples of brush-footed butterflies (family Nymphalidae) that bear a striking resemblance to modern genera.1