23-05-2025
Fossil of extinct butterfly found in Japan identified as that of new species
A fossil of a butterfly now believed extinct that was discovered in western Japan 37 years ago has been identified as that of a new species of the insect.
With an estimated wing span of 84 millimeters, it is also believed to be the largest butterfly fossil in the world, drawing attention as a valuable record for tracing the evolution of butterflies.
The finding by a team of Japanese researchers was published in the journal Paleontological Research earlier this month.
The specimen was found in 1988 in Shinonsen Town in Hyogo Prefecture from a 2.5 million-year-old stratum and has since been kept at a local museum.
The team, led by Aiba Hiroaki, a teacher at Keio Yokohama Elementary School near Tokyo, examined the fossil with a high-performance microscope. The researchers determined it was that of a new variety of butterfly based on wing and abdomen characteristics.
The researchers said butterfly fossils are extremely rare because the insect's bodies and wings are fragile and buoyant, making them less likely to be preserved as fossils compared with plants and shells.
The species, no longer found in Japan, is believed to have gone extinct. The researchers said it belongs to the Tacola genus. A related species in the group is known to exist in subtropical and tropical zones in Southeast Asia.
Aiba said that while fossils serve as proof in considering the evolution of creatures, butterfly fossils are extremely rare and limited worldwide. He added that the discovery of the world's largest butterfly fossil is scientifically highly valuable.
