Our understanding of butterfly origins is based on the study of living Lepidopteran species. We can often learn about evolution from the fossil record, but there are relatively few butterfly fossils. Those that do exist, like the 40-million-year-old Prodryas persophone, are remarkably similar to modern-day forms--so the fossil record sheds little light on the origin of today's butterflies.
Many scientists believe that the specialized association between today's butterflies and flowering plants suggests that butterflies developed during the Cretaceous Period, often called the "Age of Flowering Plants," 65 million to 135 million years ago--a time when dinosaurs also roamed the earth.
Evolutionary relationships among major Lepidopteran groups are not well understood. What we do know is that, despite the attention they receive from scientists and the public alike, butterflies are not the pinnacle of Lepidoptera evolution. One recent theory is that an obscure moth family, the Hedylidae, represents the closest living relatives of the butterflies. Essentially, this theory suggests that butterflies are just a group of brightly colored moths.