Oldest army ant found in 35-million-year-old Baltic amber

An sudden discovery in a chunk of amber saved at Harvard University for the reason that Thirties reveals that military ants as soon as lived in Europe

By Christa Lesté-Lasserre

The world’s oldest military ant has been recognized in a block of 35-million-year-old Baltic amber. The sudden discovery means that the blind, belligerent bugs – now frequent in Africa and South America – as soon as roamed the European continent.

“We didn’t think they were in Europe,” says Christine Sosiak on the New Jersey Institute of Technology. “It’s actually completely unheard of to find them there. And yet here we have this [European] army ant, from so far back in history!”

Sosiak was investigating amber-embedded ant fossils, saved at Harvard University for the reason that Thirties, when she got here throughout a specimen that seemed to be mistakenly recognized as a member of the frequent Platythyrea genus.

“I put it underneath a microscope and thought, ‘Wait, that’s definitely not the species that’s labelled [as],’” she says. “‘It’s something entirely new, something really odd and interesting.’”

Using images and microscopic CT scans, Sosiak and her colleagues created high-resolution pictures and a 3D mannequin of the well-preserved, shiny brown ant. They realised that, in contrast to most species of ants, this insect had no eyes, sharply pointed jaws, a single waist phase and a big gland that might have secreted protecting fluids obligatory for residing underground.

The findings level to a military ant employee that was carefully associated to species present in Africa, says Sosiak. Like modern-day military ants, the traditional ant most likely hunted in giant raiding swarms utilizing pheromone trails and lived a nomadic life constructing short-term underground nests.

“She probably just got lost,” Sosiak says of the fossilised ant. “She lost the pheromone trail; she veered off from it and went just a little bit too far and got stuck in tree resin.”

The crew named the ant Dissimulodorylus perseus, based mostly on the Latin phrase dissimulo – which suggests conceal or disguise, for the reason that insect’s true id eluded scientists for greater than 80 years – and in reference to the Greek mythological hero Perseus, who defeated Medusa with out having the ability to take a look at her.

The discovery represents the second confirmed military ant fossil, she says. The first – a species referred to as Neivamyrmex ectopus – was present in 16-million-year-old amber from the Dominican Republic.

While sudden, the Baltic military ant discovery is sensible contemplating that Europe was hotter and wetter in the course of the insect’s lifetime, she says.

“Army ants are such cool predators today, and they’re such integral parts of ecosystems,” says Sosiak. “And it’s just really neat to learn that they were still integral parts of ecosystems even 35 million years ago.”

Journal reference: Biology Letters, DOI: 10.1098/rsbl.2022.0398

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