That familiar jellyfish-like menace drifting onto Irish beaches? Turns out it’s not just one creature — but at least four.

New research from an international team of scientists has revealed that the bluebottle, or Portuguese man o’ war, is actually a group of distinct species, each with its own shape, genetics, and range.

“We thought they were all the same,” said Professor Kylie Pitt of Griffith University in Australia. “They’re not — and they’re not even interbreeding.”

The study, published in Current Biology, analysed over 150 specimens worldwide. It confirmed long-dismissed 18th-century theories that there were different forms — including a brand-new species, Physalia minuta, found near New Zealand and Australia.

Despite their shared ability to ride the wind using gas-filled floats, each species has evolved separately, shaped by ocean currents and wind patterns. Even within a single species, regional variations have developed.

It’s a discovery that could help improve sting forecasts — researchers in Australia are already developing prediction tools that may one day benefit beachgoers in Ireland too.

So next time a bluebottle washes up on the Irish coast — it might not be the one you think.