One of the most intriguing discoveries in entomology was just made — not in the field, but in a drawer.
Anderson Lepeco, an entomologist at the Museu de Zoologia da Universidade de São Paulo, had been combing through slabs of ancient rock in a collection from a little-known fossil site in northeastern Brazil when he saw something strange: a faint outline that reminded him of something. It wasn’t a cockroach or a cricket, the usual fare in this collection. It was something else. “When I started to look at it and compared to the fossils in Myanmar, I was just shocked,” he said. “I was very, very excited, I was jumping through the lab.”
What he found was not just any insect. It was the oldest ant ever discovered — preserved for 113 million years in limestone. And not just any ant, either. It was a hell ant.
A Predator From the Cretaceous
Hell ants, known to scientists as members of the now-extinct subfamily Haidomyrmecinae, are unlike anything alive today. Their jaws didn’t swing sideways like modern ants. Instead, they arched upward like scythes, snapping shut in a vertical motion to pin or impale prey. Such an evolutionary strategy hasn’t been seen in any other insect before or since.
The fossil, now named Vulcanidris cratensis, is a female and was likely a queen. Its name honors the Vulcano family, who donated the rock deposits from the Crato Formation to the museum. The suffix “-idris” is often used in ant taxonomy and means “the provident one.”
Using micro-computed tomography (a kind of 3D X-ray scan), Lepeco’s team peered into the stone without having to pry anything open. What they found astonished them: mouthparts so intricately specialized they rival those of any modern predator. “While we expected to find hell ant features, we were shocked by the characteristics of its feeding apparatus,” said Lepeco.
“Finding such an anatomically specialized ant from 113 million years ago challenges our assumptions about how quickly these insects developed complex adaptations. The intricate morphology suggests that even these earliest ants had already evolved sophisticated predatory strategies significantly different from their modern counterparts,” the researchers noted.
A New Timeline of Ant Evolution
Previously, the oldest known ants came from amber in France and Myanmar, dating back about 100 million years. This new specimen pushes that date back by 13 million years. More importantly, it’s the first time a hell ant has been found preserved in rock, rather than amber.
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That matters. Amber tends to preserve animals that lived in or near forests, where tree resin could entrap them. Rock fossils, by contrast, can preserve species from a wider range of environments. The Crato Formation, where Vulcanidris was found, is a renowned fossil bed that once sat in the heart of the ancient supercontinent Gondwana.
“Vulcanidris offers the first undisputed evidence of ants in South America during the Cretaceous,” Corentin Jouault, an evolutionary biologist at the University of Oxford not involved in the research, told the Washington Post. “This is a watershed moment in paleomyrmecology, reviving confidence in the potential of Cretaceous Gondwanan fossil sites to inform early ant history.”
In evolutionary terms, this suggests that ants had already spread widely across the planet by the mid-Cretaceous, well before flowering plants became dominant and before dinosaurs like Tyrannosaurus rex even existed.
But the fossil does more than shift the timeline. It suggests ants evolved complex biological machinery earlier than we thought. Hell ants might have been among the first ants to diverge from their common ancestor. The first ants are thought to have appeared sometime between the Jurassic and early Cretaceous periods.
“Finding such an anatomically specialized ant from 113 million years ago challenges our assumptions about how quickly these insects developed complex adaptations,” Lepeco explained. “The intricate morphology suggests that even these earliest ants had already evolved sophisticated predatory strategies significantly different from their modern counterparts.”
What We Still Don’t Know
The fossil is a queen, which hints at some kind of social structure, but it’s unclear if Vulcanidris lived in colonies like modern ants. “Here in this very early ant, only a queen-like specimen was found,” said Adria LeBoeuf, a zoologist at the University of Cambridge. “Will we eventually find workers? Maybe yes, but perhaps this species was not yet eusocial.”
And then there’s the question of extinction. Hell ants thrived for tens of millions of years before disappearing. What killed them off? Was it competition with other ant lineages? Shifts in climate? Or were their scythe-like jaws simply not cut out for the job long term?
Nevertheless, the story of Vulcanidris is not just about ancient insects and early ants. It’s about the value of forgotten collections. Remember, this fossil didn’t come from a shiny new expedition. It came from a dusty slab in a cabinet.
“This finding highlights the importance of thorough examination of existing collections — private or in museums,” said Lepeco. “And it brings a spotlight to Brazilian paleontology and the underexplored fossil insect fauna of the country.”
Ants are now one of Earth’s dominant life forms — 20 quadrillion strong, shaping ecosystems on every continent except Antarctica. Yet their beginning, it seems, was stranger, older, and more wondrous than we imagined.
The findings appeared in the journal Current Biology.