Long before the first sharks appeared, large predator worms were the “terror beasts” of the seas more than 500 million years ago, according to new research.
Discovery of Ancient Predator Worms
Scientists discovered fossils of the previously unknown worm species during expeditions in North Greenland, uncovering what they believe to be some of the earliest carnivorous animals.
Timorebestia: The "Terror Beasts"
The worms reached nearly 1 foot (30 centimeters) in length and were some of the largest swimming animals at the time, known as the early Cambrian Period.
Distinctive Features
Fins marched down the sides of their bodies, and their distinctive heads had long antennae and massive jaws.
Changing Views on Ancient Ecosystems
Previously, it was believed that primitive arthropods, including strange-looking distant relatives of crabs and lobsters called Anomalocaris, were at the top of the marine food chain during the Cambrian Period.
Newly Revealed Ecosystem Dynamics
But the predator worms were a key part of the ecosystem 518 million years ago that scientists didn’t even know existed until they found the fossils. The researchers named the worms Timorebestia, Latin for “terror beasts.”
Significance of Timorebestia
“Timorebestia were giants of their day and would have been close to the top of the food chain,” said senior study author Dr. Jakob Vinther, associate professor in macroevolution at the University of Bristol’s Schools of Earth Sciences and Biological Sciences.
Impact on Ancient Oceans
During the Cambrian Period when carnivorous predators appeared, “animals explosively evolved for the first time,” Vinther said. “It had a tremendous impact on the carbon and nutrient cycles as well as the pace of evolution.”
Evolutionary Connections
These predator worms are distant relatives of the much smaller modern arrow worms, or chaetognaths, that feed on zooplankton, Vinther said.
Preserved Fossil Details
Arrow worms are considered to be among the oldest animals that originated in the Cambrian Period.
Expeditions to Sirius Passet
Park led a research team on expeditions to Sirius Passet, a well-preserved fossil site in the farthest reaches of North Greenland.
Rich Fossil Deposit
The sun shines all day in the remote location, which is 600 miles (966 kilometers) from the North Pole, Vinther said. Researchers have a small window of about six weeks each year when the site is accessible, but it’s worth the trek, he said.