CAMBRIDGE, United Kingdom — Researchers in the United Kingdom have discovered a gigantic fossil of a prehistoric millipede they say lived over 100 million years before the Age of Dinosaurs. The creature, called Arthropleura, is only the third fossil of its kind and the largest as well.
In fact, from the section of the millipede’s body found on a Northumberland beach, researchers estimate that the enormous arthropod was nearly nine feet long and weighed over 100 pounds!
The discovery was a ‘complete fluke’
Researchers from the University of Cambridge say this giant millipede literally fell right into their laps. In January 2018, a large piece of sandstone broke off a cliff at Howick Bay in Northumberland, splitting open to reveal a piece of the Arthropleura fossil.
“It was a complete fluke of a discovery,” says lead author Dr. Neil Davies from Cambridge’s Department of Earth Sciences in a university release. “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 actual segment of the Arthropleura is about 75 centimeters long (roughly 30 inches). It consists of multiple hinged exoskeletal sections which resemble the body of a modern-day millipede. From their studies of the three Arthropleura fossils, scientists believe the creatures lived in the Carboniferous Period, about 326 million years ago. The Arthropleura is also the largest invertebrate (animals without backbones) ever discovered by humans.
Britain was a much different place 326 million years ago
The team notes that these creatures thrived in tropical climates near the equator, which would seem to make the United Kingdom a curious place to find one. In the Carboniferous Period, however, the land mass including Great Britain was actually down at the equator, where these invertebrates lived off of local vegetation around creeks and rivers.
Researchers also note this fossil is likely the molted outer layer of an Arthropleura shedding its exoskeleton. From there, it likely filled with sand, preserving its shape throughout time.
“It was an incredibly exciting find, but the fossil is so large it took four of us to carry it up the cliff face,” Davies adds.
Although previous studies suggested that the Arthropleura lived in coal swamps, the new study points to it preferring open woodlands where it could feast on all the local plant life.
“While we can’t know for sure what they ate, there were plenty of nutritious nuts and seeds available in the leaf litter at the time, and they may even have been predators that fed off other invertebrates and even small vertebrates such as amphibians,” Davies explains.
What killed the Arthropleura?
The reason for their extinction is still a mystery, but researchers say the rise of reptiles may have played a role. These creatures lived for around 45 million years but having to compete for food with newer animals likely brought about their end in the Permian period.
“Finding these giant millipede fossils is rare, because once they died, their bodies tend to disarticulate, so it’s likely that the fossil is a molted carapace that the animal shed as it grew,” Davies concludes. “We have not yet found a fossilized head, so it’s difficult to know everything about them.”
The findings are published in the Journal of the Geological Society.