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Giant Ancient Millipede Breaks Record For Largest Ever Arthropod


Maddy Chapman

Maddy is a Editor and Writer at IFLScience, with a degree in biochemistry from the University of York.

Editor & Writer

millipede fossil

At 2.7 meters (nearly 9 feet), the giant millipede is also the largest-ever arthropod. Image Credit: Neil Daves

A massive ancient millipede has snatched the crown for the largest ever found. Discovered on a beach in Northern England, the fossil also breaks another record – it’s the largest arthropod of all time. Knocking the sea scorpion off the top spot, the giant is estimated to measure a whopping 2.7 meters (almost 9 feet) and weigh in at 50 kilograms (110 pounds). That’s roughly the size of a car.

Just imagine that scuttling about and be thankful you weren’t around 326 million years ago to witness it.


The finding is published in the Journal of the Geological Society

The mammoth millipede, belonging to the Arthropleura genus, dates back to the Carboniferous Period – around 100 million years before the dinosaurs – and is just the third such fossil ever discovered. 

Much like modern millipedes, this old beast is made up of multiple exoskeleton segments, one of which was discovered in Northumberland in 2018. At 75 centimeters (30 inches), the segment is thought to make up about a third of the millipede’s full length. Its discovery was, apparently, a “complete fluke” as the block of sandstone containing the fossil fell from a cliff to the beach below.

“The way the boulder had fallen, it had cracked open and perfectly exposed the fossil, which one of our former PhD students happened to spot when walking by,” the paper’s lead author Dr Neil Davies said in a statement.


The segment was found in a fossilized river channel, and the team thinks it became filled with sand, hence its preservation for hundreds of millions of years. 

“Finding these giant millipede fossils is rare,” Davies said, as their bodies tend to come apart after death. He believes, therefore, that the fossil is a section of the millipede’s exoskeleton that was shed as it grew.

Rarer still is the fact that the fossil was found in sandstone, which is “is normally not brilliant for preserving fossils,” Davies told NPR.

"So the fact that this has been preserved is, on the one hand, surprising. But it just suggests that actually there might be a lot more and similar things in places where people haven't really looked for fossils before."


It’s been a record-breaking few days for the humble millipede – just last week it was crowned the leggiest animal of all time after a new species with 1,306 legs was discovered

This record discovery will shed more light on the mysteries of the millipede – its habitat, for example. While Arthropleura is known to have lived around the Equator – as Britain was during the Carboniferous – it was thought to reside in coal swamps. This specimen, however, shows they were partial to open woodlands, near the coast.

We can also learn some of the secrets of its size. It seems it can’t just be attributed to a peak in atmospheric oxygen levels, as previously thought, as the rock in which the fossil was found actually predates the spike.

"The oxygen really doesn't take off until after these things have evolved, and it doesn't really peak until after they apparently go extinct," Davies told NPR. "They don't quite match up."


So why are they quite so big?

A high-nutrient diet, apparently. Plenty of vegetation, nuts, seeds, and maybe even other critters could all contribute to their colossal size, according to Davies.

Eat up, kids.


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