Scientists Discover the Oldest Known Ant Fossil, a 113-Million-Year-Old ‘Hell Ant’ Preserved in Rock in Brazil
The odd-looking specimen with scythe-like jaws indicates that early ants were spread widely across the globe while dinosaurs still roamed
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Brazilian researchers say they’ve discovered the oldest ant fossil yet, a finding that sheds light on the insects’ evolution. The female specimen belongs to an extinct group known as “hell ants,” which are closely related to the wasp-like ancestor of ants today.
Anderson Lepeco, an entomologist at the University of São Paulo and lead author of the study, first came across the specimen in September while sifting through the collection at the university’s Museum of Zoology. He found the fossil ant preserved in limestone from Brazil’s Crato Formation, a geologic site in the northeast of the country known for its fossils.
“I was so excited, I was trying to not start screaming in the lab,” says Lepeco to Alexa Robles-Gil at Science.
Lepeco and his team used an X-ray imaging technique called micro-computed tomography to create a 3D image of the specimen. That allowed them to get a look at the ant’s unique anatomical features that were hidden inside the rock. Their findings were published in the journal Current Biology on Thursday.
“We could see incredible structures that we could not see through the photographs, like the mandibles,” says Lepeco to Victoria Craw at the Washington Post. The ant’s scythe-like jaws allowed it to impale its prey, while modern ants have lost this trait in favor of mandibles that grasp prey from the sides. They would have worked like forklifts, moving upward, Lepeco explains in an email to CNN’s Katie Hunt.
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This archaic jaw is a key trait of hell ants, an extinct group in the subfamily Haidomyrmecinae that lived during the Cretaceous period, between 66 million and 145 million years ago. This means the newly discovered hell ant was crawling around the Earth at the same time as dinosaurs. The Brazilian scientists named their specimen Vulcanidris cratensis, after the Vulcano family, which donated the rock deposits where the fossil was found to the museum.
The previous oldest known hell ant fossils were around 100 million years old, found preserved in amber in Myanmar and France. One 99-million-year-old fossil was even found preserved clutching its prey in its jaws. This new fossil shows that hell ants were widespread across the planet during the earlier end of their evolution, and it’s also the first one to be found preserved in rock instead of amber.
“From previous fossil records, we know that hell ants were successful and diverse, occurring in three continents over 20 million years,” adds Christine Sosiak, an entomologist at the Okinawa Institute of Science and Technology in Japan who was not involved in the study, to Olivia Ferrari at National Geographic. “This new hell ant really reinforces this pattern, expanding their geographic and temporal diversity.”
“We can imagine a more complex picture of the age of dinosaurs… there were incredible insects such as hell ants living together with them, that had very specialized behaviors and anatomies,” says Lepeco. “People often think only about great dinosaurs, mammals and huge animals that we find as fossils, but insects are also remarkable.”
Lepeco tells the Washington Post that he now plans to study the links between more ant fossils to paint a “more complete picture” of their evolution. As Corrie Moreau, an entomologist and evolutionary biologist at Cornell University who was not involved in the study, puts it to Science, “a single fossil can reframe how we understand the history of an entire group of organisms. That’s just phenomenal.”
