World’s oldest ant found: 113-million-year-old ‘hell ant’ fossil discovered in Brazil

Fossilised ‘hell ant’ pushes back evolutionary timeline by millions (Image: Current Biology)

When researchers carve into rocks, there aren't often surprises. But far beneath the Brazil limestone beds, scientists discovered an ant fossil like no other. It's not only old—it's older than the oldest ant known.

The 113-million-year-old fossil was unearthed in the Crato Formation in northeast Brazil. The area is already renowned for its superior fossil preservation. However, this is the first time a hell ant—part of the long-extinct Haidomyrmecinae group—has been encountered fossilised within rock instead of amber.

Major Characteristics Observed in Earlier Lineage

Reported in the journal Current Biology, the research uncovers the fossil's remarkable state of preservation. Researchers employed micro-CT scanning to generate high-resolution 3D images. The images revealed intricate jaw frameworks—like contemporary trap-jaw ants—but with characteristics specific to fossil species.

Hell ants are known for their upward-facing jaws that snap shut like traps. (Image: Current Biology)

Hell ants have their jaws snapping shut like traps pointed upwards. These specialised mouthparts indicate that these insects were already efficient predators in the early phases of ant evolution.

The new fossil reveals that ants not only existed much earlier than initially considered but were by then already diverse and present in a wide range across the globe. It discredits previously held notions concerning the time and place at which ants initially evolved.

An Unusual Find in Stone, Not Amber

Earlier, all hell ants that had been discovered were preserved in amber from France and Myanmar. This fossil, which was preserved in limestone, is of a different preservation type. It enabled researchers to examine characteristics not apparent in amber specimens.

The lead researcher, Anderson Lepeco of the Museu de Zoologia da Universidade de São Paulo, described the discovery as the "earliest undisputable geological record of ants." He explained further that the precise anatomy also showed surprising complexity in the insect's feeding system.

The ant also resembles species from Burmese amber, indicating that hell ants were more widely distributed than previously thought. This lends credence to hypotheses of early global expansion of ant species.

Early Ant History Now Better Revealed

The research sheds new light on early ant history. It indicates that the insects were already exhibiting specialist roles and sophisticated survival mechanisms millions of years ago.

Scientists say that this new species contributes to the diversity from that era. It also resets the ant evolutionary timeline, showing how tiny they were yet already occupying ecological niches at early stages.

This discovery not only adds a new species to the record but also sheds more light on the development of ants through the ages.