A new study published in the journal Science Advances has revealed that the pelagic ecosystem and fossilized organisms at Sirius Passet show that more than 518 million years ago, the worm was one of the largest predators. The findings, which were led by Bob Nicholls of the University of Bristol, shed light on the diversification of animals across the Ediacaran-Cambrian transition.
The discovery of fossils of a new group of predatory animals in the Lower Cambrian locality of Sirius Passet, in northern Greenland, has provided insight into the early colonization of the water column by large worms. These creatures, known as Timorebestia, measured over 30cm long, making them some of the largest swimming animals of the Early Cambrian. Equipped with fins, a distinctive head with long antennae, and huge jaw structures, these worms were some of the earliest carnivorous animals to dominate the water column.
The researchers found that Timorebestia is distantly related to living arrow worms or chaetognaths, which are much smaller ocean predators that feed on tiny zooplankton. This finding suggests that the ancient ocean ecosystems were complex and had a diverse food chain that allowed for various levels of predators.
These new fossils are significant because they provide valuable insight into where jawed predators, such as arthropods, originated from. The researchers believe that Timorebestia and arrow worms likely dominated the oceans before arthropods took over, signifying a dynasty that lasted approximately 10 to 15 million years.
The study was conducted over a series of expeditions to Sirius Passet in northern Greenland, where the scientists collected a wide variety of new organisms. The remarkably preserved fossils from this remote site have allowed researchers to reveal interesting anatomical details, such as digestive system, muscular anatomy, and nervous system, providing valuable information about the ancient pelagic ecosystem.
Dr. Jakob Vinther, a researcher at the University of Bristol, who co-authored the study, expressed the significance of the discovery in understanding the evolution of jawed predators. This remarkable find has unveiled a new chapter in the ancient history of marine predators and their evolution, shedding light on the origins of predatory animals that dominated the oceans more than 500 million years ago.