A new species of Alaskan butterfly has been discovered for the first time in nearly 30 years.
The US state of Alaska is famous for its extreme seasonal changes - with high temperatures in summer, and freezing cold in winter, meaning that only the toughest animals can survive.
The Oeneis Tanana is a rare cross between two other species of arctic butterfly, and its inherited some of their best features for coping with the extreme conditions.
One of its ways to cope with the cold is to produce a substance that stops its blood from freezing in winter while it hibernates, a bit like the antifreeze liquid that's used to stop car windscreens getting icy.
Scientists think that the Oeneis Tanana may be the only species of butterfly that's unique to Alaska, and can't be found anywhere else in the world.
Butterflies are particularly quick to react to climate change, so scientists hope that monitoring the Oeneis Tanana could help them to understand changes to the Arctic environment.