500m-year-old fossils of “terror beast” worms discovered 

The fossils of a new group of early carnivorous worms have been discovered in North Greenland. They have been named Timorebestia – meaning “terror beasts” in Latin. 

The fossilised animals, which were found in the Early Cambrian Sirisus Passet fossil locality, may have been some of the earliest carnivorous animals to colonise the water column more than 518 million years ago. 

Timorebestia is a distant, but close, relative of living arrow worms, or chaetognaths. These are much smaller ocean predators today that feed on tiny zooplankton,” explains Dr Jakob Vinther, a researcher at the University of Bristol in the UK, a senior author on a new study describing the discovery in Science Advances. 

The beasts grew fins down the sides of their body, long antennae, had massive jaw structures inside their mouth, and grew to more than 30cm in length. It might not sound like much, but they were some of the largest swimming animals in the Early Cambrian times. 

“Our research shows that these ancient ocean ecosystems were fairly complex with a food chain that allowed for several tiers of predators,” says Vinther. 

Timorebestia were giants of their day and would have been close to the top of the food chain. 

“That makes it equivalent in importance to some of the top carnivores in modern oceans, such as sharks and seals back in the Cambrian period.” 

Fossil of timorebestia kopri
Fossil of Timorebestia koprii – the largest known specimen, almost 30cm or 12 inches long. Credit: Dr Jakob Vinther

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