Scientists Stumble on Fossilized Remains of an Ancient Millipede, Shed Light on Why These Creatures Were So Big

The surprise discovery of a giant millipede fossil as big as a car in England has provided new clues about why these prehistoric animals evolved to become so massive, according to the Journal of the Geological Society. The fossilized remains were discovered on a Northumberland beach about 40 miles north of Newcastle and are only a part of what researchers think was a creature that measured 2.7 meters in length and weighed up to 50 kilograms.
A giant millipede fossil, Arthropleura, was found on a Northumberland beach in England. Dating back to the Carboniferous Period (326 million years ago), it measured over 2.5 meters long and weighed about 50 kilograms. The discovery was made by chance after a cliff collapsed. pic.twitter.com/MArVcMXNOG
โ ๐๐ก๐ ๐ ๐๐๐ฎ๐ฅ๐จ๐ฎ๐ฌ ๐๐๐ข๐ซ๐ ๐๐ซ๐จ๐ญ๐ญ๐๐ซs (@FabulousWeird) June 12, 2024
"Just as it was getting dark, we saw that there was a boulder that had fallen from the cliff," recalled Neil Davies, an Earth scientist at the University of Cambridge, who found the remarkable site on a social trip with his Ph.D. students back in January 2018, according to NPR. It wasn't a clear find, but they only confirmed their suspicion by returning the following morning for close-ups.
The fossil comes from the Carboniferous, a period in geological history between 346 and 295 million years ago when the position of England was much nearer the equator. What made this find pretty remarkable was a matter of sheer rarity: less than a couple of other relatively whole fossilized Arthropleura specimens have previously been found, none of which rivals the size of this one.
Davies explained that the scarcity of such fossils likely stems from the creatures' tendency to shed their carapace during molting rather than preserving complete bodies after death. In those rare instances, "people have found fragments of skeletons, individual legs or individual bits of skeleton, but not something [like this] that's kind of articulated," Davies said, as per NPR.

It was a wonder that fossils had been preservedโthis rarely happens because the sandstone composition in Northumberland doesnโt easily allow fossils to form. The find contradicts previous theories on the gigantic size of these creatures. While high atmospheric oxygen levels during the late Carboniferous and Permian periods were thought to explain their massive proportions, this fossil predates that oxygen peak. "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 pointed out, as per NPR.
A colossal millipede fossil,the size of a car,has been discovered on a beach in northern England.The fossil belongs to a creature known as Arthropleura,wch lived during the Carboniferous Period roughly 326M yrs ago.
โ Edward Elderman (@edwereddie) February 17, 2023
Guessing the atmosphere then was overdosed with oxygen. pic.twitter.com/9QoIbWgPSC
Instead, the research suggests that environmental factors played a more crucial role in their evolution. The abundance of vegetation and, at the same time, the scarcity of competing species during the time of the arthropod colossals created perfect conditions under which these animals could reach the sizes they achieved. These may have developed to counter the depredations from predators or be better predators.
This discovery sets a new record for the largest-known arthropod and has also provided useful information on the habitat preference of the creature. Whereas previously it was assumed to be placed mainly in coal swamps, this specimen shows that they could thrive in open wooded habitats near sandy coastlines traversed by small rivers, adding to our knowledge of these fascinating prehistoric giants, stated The Coversation.