Dinosaur-Era 'Hell Ant' Immortalized in Amber While Killing a Cockroach

A hell ant that lived 99 million years ago has been discovered trapped in a piece of amber, in the process of killing a prehistoric extinct cockroach relative. The ant, Ceratomyrmex ellenbergeri, is one of 16 hell ant species, 14 of which were discovered in the last decade.

Hell ants are known from amber deposits that date back between 78 and 100 million years ago. They have been found in Canada, France and Myanmar. They are unusual insects that had anatomical features unlike any species living today. One, for example, is known as Linguamyrmex vladi, or "Vlad the Impaler," named so because it used a horn on its head to impale prey.

"The head anatomy of hell ants is totally distinct from the 15,000 ant species we know of today," Phillip Barden, from the New Jersey Institute of Technology, who studies hell ants, told Newsweek.

The amber specimen with the hell ant and cockroach was discovered in 2017 in Kachin State, Myanmar. Analysis of the fossil has now been published in the journal Current Biology. This species is known for having a long horn on its head.

hell ant
Hell ant and cockroach trapped in amber 99 million years ago. NJIT, Chinese Academy of Sciences and University of Rennes, France

Barden, who is the lead author on the study, said in C. ellenbergeri would have used its long horn and jaws to collar its prey around its neck. "Once the prey was gripped in this way, the ant most probably moved on to an immobilizing sting—we know that the stings of hell ants were well developed," he said. "The way the prey is gripped confirms that hell ants moved their mouthparts up-and-down, instead of vertically as we see in living ants and essentially all insects.

"This vertical mandible movement is what we think led to the evolution of all kinds of strange horns and mouthparts in this ancient lineage."

Researchers say the discovery of a predation event preserved in this way is extremely rare. Normally, the fossilization process will wipe away any evidence of this sort of behavior as organisms move and decompose.

Hell ants are believed to have gone extinct with the dinosaurs during the mass extinction event that took place 66 million years ago. Barden said seeing how hell ants attacked prey provides an insight into how these creatures, which he dubs "evolutionary experiments," came to be—and how they differ to ant species living today.

He called the consequences of these ants moving their mouths vertically "remarkable."

"While no modern ants have horns of any kind, some species of hell ant possess horns coated with serrated teeth, and others like Vlad are suspected to have reinforced its horn with metal to prevent its own bite from impaling itself," he said in a statement.

Researchers now hope to find more hell ants to better understand how extinction impacts group morphology. "Over 99 percent of all species that have ever lived have gone extinct," said Barden. "As our planet undergoes its sixth mass extinction event, it's important that we work to understand extinct diversity and what might allow certain lineages to persist while others drop out."