An almost overlooked fossil discovered in a Brazilian museum collection has revealed the oldest ant specimen known to science, according to new research.
The prehistoric ant lived among dinosaurs 113 million years ago — several millions of years before previously found fossilized ants — and had an unusual way to kill its prey. Anderson Lepeco, a researcher at the Museum of Zoology of the University of São Paulo, said he came across the “extraordinary” specimen in September 2024 while examining a fossil collection housed at the Museum of Zoology of the University of São Paulo.
The museum has one of the world’s largest collections of fossilized insects and contains specimens from northeastern Brazil’s Crato Formation, a geological deposit renowned for its exceptional fossil preservation.
Preserved in limestone, the newly described extinct insect is what’s known as a hell ant, a member of a subfamily called Haidomyrmecinae that lived during the Cretaceous period between 66 million and 145 million years ago and is not related to any ant alive today, according to a study published Thursday in the journal Current Biology. The fossil species, which has been named Vulcanidris cratensis, had scythe-like jaws that it likely used to pin or impale prey.
“I was just shocked to see that weird projection in front of this (insect’s) head,” Lepeco, the study’s lead author, said. “Other hell ants have been described with odd mandibles, but always as amber specimens.”
It’s rare to find insects preserved in rock. Other hell ants from the Cretaceous have been found entombed in amber from France and Myanmar but they date back to around 99 million years ago. That a hell ant lived before that in what’s now Brazil means ants were already widely distributed across the planet at an early point in their evolution, the study authors noted.
The discovery sheds light on how ants evolved during the early Cretaceous, a time of significant change. It also offers some insight into unusual features in ant species of this period that didn’t survive the mass extinction that ended the dinosaur era, the researchers said.
Anatomical features lost to time
Today, ants are one of the most conspicuous and abundant groups of insects on the planet, found on all continents except Antarctica, the study noted.
However, ants haven’t always been dominant. They evolved during the late Jurassic and early Cretaceous, roughly 145 million years ago, when ant ancestors diverged from the same group that would give rise to wasps and bees.
It wasn’t until after an asteroid strike doomed the dinosaurs and other species to extinction 66 million years ago that ants became the most common insect found in the fossil record, according to the study.
The fossil is a “pretty big deal,” said Phil Barden, an associate professor at the New Jersey Institute of Technology who studies the evolutionary history of insects.
“This new find now represents the oldest ant known, it extends the known fossil record for ants by about ten million years,” Barden, who wasn’t involved in the study, said via email.
“Although fossil ants have been described since the 19th century…Until now, it was not clear if the absence of ants older than 100 million years was because they were not around or just that they were not preserved in deposits where people were looking,” he added.
The newly identified species also had some wasp-like characteristics indicative of the common ancestry between the two creatures. For example, the ant’s wings had far more veins than those of living ants, Lepeco said.
Micro-computed tomography imaging — a 3D-imaging technique that employs X-rays to view inside the ant — revealed that the bug was closely related to hell ants previously known only from Burmese amber fossils.
What was most striking about the ant was its unusual anatomical features. Modern ants have jaws that grasp laterally — side to side. However, this ant possessed scythe-like jaws that ran parallel to its head and projected forward from near the eyes, the researchers noted in the study.
“It could have worked as a kind of forklift, moving upwards” as the ant preyed on other extinct insects, Lepeco explained via email.
“The intricate morphology suggests that even these earliest ants had already evolved sophisticated predatory strategies significantly different from their modern counterparts,” Lepeco added.