SFU paleontologists Bruce Archibald and Rolf Mathewes and two colleagues have discovered a fossilized hummingbird-sized ant unearthed in Wyoming that sheds light on how global-warming events affected the distribution of life 50 million years ago.

The researchers, who reported their discovery May 3 in the journal Proceedings of the Royal Society B, have dubbed the new species Titanomyrma lubei. The 5.1-cm ant is related to giant ants previously found in German fossils.

The ant’s discovery lends credence to the idea that brief periods of global warming allowed hot-weather-loving large insects to migrate between continents during the Eocene Epoch across an Arctic land bridge from Europe to North America.

Archibald stumbled across the ant fossil while he and study co-author Kirk Johnson, a paleontologist at the Denver Museum of Nature & Science, were rummaging through a museum storage drawer.

“What is surprising is that this ant scurried about an ancient forest in what is now Wyoming when the climate there was hot like the modern tropics,” says Archibald.

“In fact, all of the closely related fossil giant ants have been found in Europe and North America at sites that had hot climates.”

The researchers also noted that almost all of the largest modern ants live in the tropics, indicating there might be something about being big that requires ants to live in hot temperatures.

Archibald says his team’s findings will help scientists gain a better grasp of the impacts of global warming on life.

“As the Earth’s climate changes,” he says, “we are seeing tropical pest species extend their ranges into mid-latitudes and dragonflies appear in the Arctic.

“Understanding the details of how life forms adapted to global warming in the past will be of increasing importance in the future.”