A 425 million year old predatory worm that moved like an accordion? Why not

A remarkable fossil of a worm has been described, estimated to be about 425 million years old and the youngest species of its group to be classified. The carnivorous burrowing predator was collected from Leintwardine in Herefordshire and has been given a name Radnorscolex latus by scientists from the London Natural History Museum.

Radnorscolex It is thought to have moved across the seabed like an accordion, using a set of sharp teeth and hooks on its head to anchor itself as it shuffled. The feeding mechanism has been compared with that of Dune‘s sandworms, which eat anything unlucky enough to cross its path. What could that have entailed?

“Probably something unfortunate enough to have been lying in the mud in front of it so it could fit down his throat,” said lead author Dr. Richie Howard, curator of Fossil Arthropods at London’s NHM, told IFLScience. “So probably various small invertebrates, including other smaller species of worms. Fossils from the Cambrian of Greenland and China show paleoscolecidal viscera filled with sediment, and traces of elongated clusters of fossilized fecal pellets have been reported associated with paleoscolecids from the Ordovician of Morocco. This all indicates that they swallowed and defecated a lot of mud in their search for prey!’

a scan of a prehistoric predatory worm fossil that is 425 million years old

“We know that this fossil was studied in 1920, but without the advanced technology we have today using state-of-the-art imaging techniques, they would not have been able to describe them as accurately and precisely as we can now.”

Image credit: Richie Howard and Luke Parry

The description is new to science, but the fossil has been circulating in museum collections for some time – recovered sometime in the 1920s from a disused Victorian quarry in Herefordshire, UK. As for how a worm ends up in the fossil record in a way that is still observable 425 million years later, it all comes down to their armor.

“Palaeoscolecides are ecdysozoans – invertebrates with a hard cuticle made of chitin (like an arthropod exoskeleton),” Howard added. “As such, their skin was very tough and more resistant to the forces of decay than, say, an earthworm. Furthermore, ecdysozoans must molt their tough cuticle periodically in order to grow, which increases the likelihood of their preservation as a fossil (i.e. one worm can produce multiple fossils over its lifetime as it molts, as well as a final carcass when it dies). .”

It was being studied at the time of its discovery, but without the advanced technology available in scientists’ arsenal today, researchers of the time were unable to get to the bottom of what they were looking at. Using advanced scanning technology, the current team of scientists has managed to describe the worm and find clues about its position in the ecosystem. It appears that Radnorscolex was remarkable even in its heyday.

“What we found is quite rare, as we may be looking at the modern-day equivalent of a living fossil, but from a Silurian perspective,” Howard explained in a statement. “Just as we see coelacanths or horseshoe crabs today, groups that have been around for so long exist as very old fossils, but also appear millions of years later in present times as low-diversity groups.”

Close-ups reveal the pattern of armor plates on the prehistoric worm Prehistoric worm Radnorscolex latus.

Close-ups reveal the pattern of armor plates on the prehistoric worm Radnorscolex latus.

Image credit: Richie Howard and Luke Parry

“We know that this fossil was studied in 1920, but without the advanced technology we have today using the most modern imaging techniques, they would not be able to describe it as accurately and precisely as we can now. We hope that this study will lay the foundation for future research on Silurian paleoscolecides.”

The study was published in the journal Papers in Paleontology.

This article was amended on May 23, 2024 to include original quotes from the researchers.

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