Paleontologists have described the oldest known member of Haidomyrmecinae — an extinct subfamily of ants that only lived during the Cretaceous period — preserved as a rock impression in the limestone of the Crato Formation in northeastern Brazil.
Vulcanidris cratensis, holotype. Scale bar – 2 mm. Image credit: Lepeco et al., doi: 10.1016/j.cub.2025.03.023.
Named Vulcanidris cratensis, the new ant species lived 113 million years ago (Early Cretaceous epoch).
The species represents the oldest definitive ant known to science and also the most complete evidence for the early evolution of ants in the fossil record.
“Vulcanidris cratensis represents the earliest undisputable geological record of ants,” said author Dr. Anderson Lepeco, a paleontologist at the Museu de Zoologia da Universidade de São Paulo.
“What makes this discovery particularly interesting is that it belongs to the extinct ‘hell ant,’ known for their bizarre predatory adaptations.”
“Despite being part of an ancient lineage, this species already displayed highly specialized anatomical features, suggesting unique hunting behaviors.”
The previous oldest ants were found in France and Myanmar and were preserved in amber instead of limestone.
The existence of a hell ant in Brazil shows that ants were already widely distributed and diversified early in their evolution.
“Even though there have been hell ants described from amber, this was the first time we could visualize this in a rock fossil,” Dr. Lepeco said.
Dr. Lepeco and colleagues discovered the remarkably well-preserved ant specimen while systematically examining one of the world’s largest collections of fossil insects from the Crato Formation, a deposit renowned for its exceptional fossil preservation.
“When I encountered this extraordinary specimen, we immediately recognized its significance, not only as a new species but as potentially the definitive evidence of ants in the Crato Formation,” Dr. Lepeco said.
“This finding highlights the importance of thorough examination of existing collections — private or in museums — and brings a spotlight to Brazilian paleontology and the underexplored fossil insect fauna of the country.”
Using micro-computed tomography imaging, the paleontologists found that Vulcanidris cratensis was closely related to hell ants previously known only from specimens preserved in Burmese amber from Myanmar.
The finding shows that the ants were widely distributed across the globe and must have crossed Cretaceous landmasses repeatedly.
But what astonished them most was the hell ant’s specialized features.
“While we expected to find hell ant features, we were shocked by the characteristics of its feeding apparatus,” Dr. Lepeco said.
“Unlike modern ants with laterally moving mandibles, this species possessed mandibles that ran forward parallel to the head and facial projection anterior to the eyes.”
“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 discovery of this new ant specimen raises broader questions about the evolutionary pressures that led to the hell ant’s unique adaptations.”
“With advanced imaging tools, it’s now possible to examine such fossil specimens in much greater detail than ever before.”
The discovery of Vulcanidris cratensis is reported in a paper published today in the journal Current Biology.
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Anderson Lepeco et al. A hell ant from the Lower Cretaceous of Brazil. Current Biology, published online April 24, 2025; doi: 10.1016/j.cub.2025.03.023
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