Scientists in Australia have discovered a new species of millipede that lives 200 feet underground, has no eyes, and scurries around on 1,306 legs.
They named it Eumillipes persephone after Persephone, the Greek goddess and queen of the underworld. But this new invertebrate deserves a crown for another reason: It has the most legs of any creature on Earth, living or dead.
In fact, the competition isn’t even close. The largest specimen of the new species, a female, was less than four inches long, yet easily beat out the previous world-record holder, Illacme plenipes, a millipede that lives near Silicon Valley, California, and has 750 legs.
This means that E. persephone is the world’s first true millipede, since the word millipede means “thousand feet” in Latin, according to a new study published December 16 in the journal Scientific Reports.
While the new animal’s leg count is unprecedented, it may not even be the limit of what’s possible. (Read about the discovery of a glowing millipede.)
Many millipede species begin life with just eight legs, but as they shed their skin and add new body segments, or rings, they can keep developing more legs, says study leader Paul Marek, a millipede expert at Virginia Polytechnic Institute and State University.
“So there’s probably an individual out there with more rings and more legs, and that’s kind of hard for me to wrap my mind around,” says Marek, also a National Geographic Explorer.
In 2020, Marek’s colleagues, led by Bruno Buzatto of Australia’s Macquarie University, traveled to the Goldfields region of Western Australia to search for millipedes and other subterranean critters.
This area is known for its rich gold and nickel deposits, which mining companies identify by boring deep exploratory holes into the earth. Each hole is less than six inches wide: just big enough to lower a trap that catches the tiny creatures that manage to exist in such places. (Read about giant ancient millipede fossils found in Canada.)
These traps—a length of PVC pipe stuffed with wet vegetation and attached to a nylon cord—can be left underground for months. During that time, underground dwellers, such as millipedes, are attracted to the tasty rotting plants and get stuck inside.
That's how the team found E. persephone. Back in his Virginia laboratory, Marek uncoiled the specimen, then took high-resolution microscopic images of its body. On these images, he digitally marked the animal's body sections in increments of 10, a strategy to ensure he didn't double-count the legs. The final tally revealed 1,306 individual limbs.
So why all the legs? The team suspects they allow E. persephone to walk on eight different planes simultaneously.
“Since it is a subterranean microhabitat with rocks, pebbles, and soil, they’re basically winding their way around these obstacles,” says Marek, who received funding from the National Science Foundation.
“Part of your body can be upside down. The other part could be pointing downward, the other part could be pointing upwards. And it’s all based on winding around this three-dimensional kind of matrix,” he says.
It’s likely the millipede’s ancestors were once widespread on or close to the surface, but that an increasingly dry climate pushed them farther and farther below ground, he added.
Hidden from the sun, the creatures evolved to be colorless—a trait shared by many cave-adapted species. The thousand-leggers appear to have evolved cone shaped heads, massive antennae, and a powerful, worm-like locomotion that allows them to barrel through sediments and other tight spaces.
An unknown world beneath our feet
“A new species is always exciting, whether you’re the one discovering it or not,” says Bruce Snyder, a soil ecologist at Georgia College and State University. “But in terms of the millipede community, we’re constantly finding new species.”
Still, the fact that E. persephone has nearly twice as many legs as the next leggiest millipede is “astounding,” says Snyder, who was not involved with the research.
Snyder says it’s probably even more scientifically interesting that the new species comes from an entirely different taxonomic group than the previous record-holder, l. plenipes. This suggests that extreme many-leggedness is evolving independently as a successful adaptation to subterranean living. (See a video of millipedes swarming in Senegal.)
The depth of E. persephone’s kingdom is also surprising.
“I quite often get the question, How deep do they go?” says Snyder. “This is way deeper than I thought we would be finding much of anything.”
In general, the subterranean world is vastly understudied, making it unclear how widely distributed this species and its relatives may be.
“It goes to show that despite more than 200 years of exploration,” Marek adds, “there are still these unexplored ecosystems.”
The National Geographic Society, committed to illuminating and protecting the wonder of our world, funded Explorer Paul Marek’s work. Learn more about the Society’s support of Explorers highlighting and protecting critical species.