The remains of some enormous and extinct carnivorous worms, nearly half a billion years old, have been discovered near North Greenland. The ancient creature, named Timorebestia, or ‘terror beasts’ in Latin, lived over 518 million years ago. The new fossils indicate that the worms had fins on the sides of their bodies, a head with a long antenna, and enormous jaw structures on the insides of their mouth. These were some of the largest swimming animals of the Early Cambrian period and are described in a study published January 3 in the journal Science Advances.
[Related: A three-eyed organism roamed the seas half a billion years ago.]
An ‘explosion’ of life
Timorebestia lived during the Cambrian Explosion when most major groups of animals first appear in the fossil record as a result of cooler temperatures and tectonic changes. All of this biological diversification occurred in in around 30 million years.
The Timorebestia fossils were found during a 2017 expedition to the Early Cambrian Sirius Passet fossil locality. They reveal a potential dynasty of predators previously unknown to scientists. “Our research shows that these ancient ocean ecosystems were fairly complex with a food chain that allowed for several tiers of predators,” study co-author and University of Bristol paleontologist Jakob Vinther said in a statement.
Timorebestia is also a distant but close relative of living arrow worms called chaetognaths. These worms are much smaller than today’s enormous ocean predators and only eat zooplankton, a far cry from their apex predator days of the past.
Opening a 518 million-year old digestive system
The fossils from the Sirius Passet were exceptionally well preserved so the team was able to study the remains of their muscle anatomy, nervous systems, and digestive systems very closely. When they looked inside Timorebestia’s fossilized digestive system, they found the remains of a common, swimming arthropod called Isoxys.
