Imma Perfetto
Cosmos science journalist
Ants crawl and tunnel their way through almost every landmass on Earth today – except Antarctica and some remote or inhospitable islands. This wasn’t always the case, but new research suggests that ants had made their way into global ecosystems earlier than previously thought.
“Our team has discovered a new fossil ant species representing the earliest undisputable geological record of ants,” says Anderson Lepeco from the Museum of Zoology of the University of São Paulo in Brazil.
Lepeco and his collaborators discovered the 113-million-year-old fossil in a collection unearthed from the Crato Formation in northeastern Brazil.
According to an article describing the specimen in the journal Current Biology, the new species (Vulcanidris cratensis) was a member of the extinct subfamily Haidomyrmecinae: “What makes this discovery particularly interesting is that it belongs to the extinct ‘hell ant,’ known for their bizarre predatory adaptations,” says Lepeco.
“Despite being part of an ancient lineage, this species already displayed highly specialised anatomical features, suggesting unique hunting behaviours.”
These menacing insects lived during the Cretaceous period and had highly specialised, scythe-like jaws that they likely used to pin or impale prey. The oldest hell ant specimens before now, dating to about 100 million years ago, were preserved in amber in France and Burma.
Micro-computed tomography imaging – a 3D imaging technique that uses X-rays to view the inside of an object – showed that the new species was closely related to hell ants previously known only from specimens preserved in the Burmese amber.
The finding indicates that hell ants may have been the oldest major group of ants to diversify and spread across the globe and must have crossed Cretaceous landmasses repeatedly.
“Even though there have been hell ants described from amber, this was the first time we could visualise this in a rock fossil,” says Lepeco.
But, while the team expected to find hell ant features, Lepeco says they were shocked by the new species’ feeding apparatus.
Unlike modern ants, which have jaws that move side to side (laterally), the new species’ jaws ran parallel to its head and moved in a forward motion (ventrally) to grasp its prey.
“Finding such an anatomically specialised ant from 113 million years ago challenges our assumptions about how quickly these insects developed complex adaptations,” says Lepeco.
“The intricate morphology suggests that even these earliest ants had already evolved sophisticated predatory strategies significantly different from their modern counterparts.”
