A new animal predator fossil group has been found in the fossil locality of Early Cambrian Sirius Passet in North Greenland.
Animal Predators
These massive worms could be some of the earliest carnivorous creatures that colonized the water column over 518 million years ago. They shed light on a historic predatory dynasty that remained unknown to the scientific community.
These fossil creatures have been named Timorebestia, which translates to "terror beasts" in Latin. The creatures have fins on their sides and a unique head with long antennae. They also have huge jaw structures within their mouths that grow to over 30 centimeters in length. They were some of the biggest swimming creatures in the early Cambrian periods.
Dr. Jakob Vinther from the Schools of Earth Sciences and Biological Sciences at the University of Bristol explains that they previously knew that primitive arthropods were the Cambrian's dominant predators. However, the Timorebestia is a distant yet close relative of chaetognaths, or living arrow worms. At present, these are tinier ocean predators that consume small zooplankton.
Their research reveals that these prehistoric marine ecosystems were quite complex, having a food chain that enabled several predator tiers. During their day, timorebestia were giants that may have been close to the peak of the food chain. This makes these massive worms equivalently important as some of modern oceans' top carnivores, such as seals and sharks.
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Predator Worms
In the fossilized digestive system of the creature, the scientists found the remains of a swimming common arthropod known as Isoxys. Morten Lune Nielson, a former PhD student from the university who participated in the study "A giant stem-group chaetognath," explains that they can see that the arthropods serve as a food source for various animals. These were quite common in the Sirius Passet and had protective long spines that were pointing both backward and forward.
It appears that Timorebestia munched on great quantities of these worms. Such arrow worms are among the oldest animal fossils in the Cambrian. While such arthropods appear in the fossil record from roughly 521 to 529 million years ago, they can be traced back to 538 million years or more.
According to Dr. Vinther, both the primitive Timorebestia and the arrow worms were swimming predators. With this, they could surmise that they were predators that used to dominate the oceans prior to the taking off of arthropods.
Luke Parry, one of the study's authors from Oxford University, explains that the TImorebestia finding is quite significant when it comes to understanding where the jawed predators were from. At present, arrow worms have menacing bristles on the external part of their heads. They use it for catching prey. On the other hand, Timorebestia had jaws within its head.
Tae Yoon Park, a senior author from the Korean Polar Research Institute and the leader of the field expedition, explains that their discovery supports the evolution of arrow worms. Arrow worms that are alive today have a unique nervous center at their belly known as the ventral ganglion. This feature is fully unique to the species.
They were able to discover this preserved in Timorebestia and in a different fossil known as Amiskwia.
Dr. Pank concludes that they have more exciting finds to reveal in the years to come that can shed light on the looks and evolution of the earlier ecosystems of animals.
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