Scientists Unearth 113-Million-Year-Old ‘Hell Ant’ Fossil, the Oldest Known Specimen, Preserved in Brazilian Rock

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The odd-looking specimen with scythe-like jaws indicates that early ants were spread widely across the globe while dinosaurs still roamed

Sara Hashemi – Daily Correspondent

April 28, 2025 3:18 p.m.

Research from Brazil highlights a groundbreaking discovery in the world of entomology: the oldest known ant fossil, dated at 113 million years old, belonging to a unique group known as “hell ants.” This remarkable specimen provides critical insights into the evolution of ants, connecting them to their wasp-like ancestors.

The fossil, identified as Vulcanidris cratensis, was uncovered by Anderson Lepeco, an entomologist from the University of São Paulo, during his examination of the university’s collection at the Museum of Zoology. Found in limestone from the Crato Formation, a well-known fossil site in Brazil, this discovery marks a significant advancement in understanding the historical distribution of ants.

Lepeco was thrilled upon discovering the specimen, sharing his excitement with Alexa Robles-Gil from Science: “I was so excited, I was trying to not start screaming in the lab.”

To analyze the ant’s distinct anatomical features, Lepeco and his team employed micro-computed tomography (micro-CT), which allowed them to visualize elements of the specimen that were previously obscured. Their discoveries were published in the journal Current Biology.

“We could see incredible structures that we could not see through the photographs, like the mandibles,” Lepeco explained to Victoria Craw from the Washington Post. These scythe-like jaws were essential for impaling prey, a trait that modern ants have lost in favor of jaws adapted for grasping. Lepeco noted that these jaws functioned somewhat like forklifts, effectively moving prey upwards.

Belonging to the subfamily Haidomyrmecinae, hell ants thrived during the Cretaceous period, suggesting that this newly identified species coexisted with dinosaurs. The name Vulcanidris cratensis pays tribute to the Vulcano family, benefactors who donated the rock deposits where the fossil was extracted.

Prior to this discovery, the oldest hell ant fossils were about 100 million years old and had been found in amber located in Myanmar and France. One notable fossil was even discovered with its prey still held in its jaws. The current finding illustrates that hell ants had a broader geographical spread and adaptability during earlier phases of their evolution and is the first example preserved in rock rather than amber.

Christine Sosiak, an entomologist from the Okinawa Institute of Science and Technology, who did not participate in the study, stated, “From previous fossil records, we know that hell ants were successful and diverse, occurring on three continents over 20 million years. This new hell ant really reinforces this pattern, expanding their geographic and temporal diversity.”

Lepeco emphasized the importance of understanding the ecosystem of the dinosaur age, noting that alongside these colossal creatures, there existed a variety of intriguing insects, including hell ants, each exhibiting specialized behaviors and physical features. He aims to delve deeper into the evolutionary connections among various ant fossils to create a more comprehensive narrative of their development. As Corrie Moreau, an entomologist and evolutionary biologist at Cornell University, pointed out, “A single fossil can reframe how we understand the history of an entire group of organisms. That’s just phenomenal.”

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