A giant ‘swimming head’ lived in our oceans 500 million years ago

(CNN) – 500 million years ago, the oceans were teeming with life that looked more like aliens than the marine animals we know today. Now researchers have discovered the fossil of an unusual creature that was likely a giant compared to the tiny marine life of 500 million years ago.

Radiodonts, a group of early arthropods, became widespread after the Cambrian explosion 541 million years ago, a time when a multitude of organisms suddenly appeared on Earth, according to the fossil record.

The newly discovered fossil belonged to Titanokorys gainesi, a radiodont that reached half a meter in length and was huge compared to other ocean creatures that were about the size of a little finger.

The fossil was found in Cambrian rocks in Kootenay National Park, located in the Canadian Rockies. A study detailing the fossil was published Wednesday in the journal Royal Society Open Science.

“The size of this animal is absolutely mind-boggling, this is one of the largest Cambrian period animals ever found,” said study author Jean-Bernard Caron, curator of invertebrate paleontology at the Royal Ontario Museum Richard M. Ivey, it’s a statement.

Titanokorys would have been a bewildering animal. It had multifaceted eyes, a pineapple-slice shaped mouth that was filled with teeth, and spiny claws located under its head to catch its prey. The body of the animal was equipped with a series of fins that helped it to swim. And Titanokorys had a large-headed shell, or a defensive covering, like the shell of a crab or a tortoise.

“Titanokorys are part of a subgroup of radiodonts, called hurdiids, characterized by an incredibly long head covered by a three-part shell that took on countless forms. The head is so long relative to the body that these animals are really little more than heads. swimmers, “study co-author Joe Moysiuk, a doctoral student in ecology and evolutionary biology at the University of Toronto, based at the Royal Ontario Museum, said in a statement.

Researchers are still trying to understand why some radiodonts had such a variety of head shells, which came in all shapes and sizes. It is unclear what this hull was protecting them from, given their size compared to other marine species at the time. In the case of Titanokorys, the broad, flat carapace suggests that it had adapted to live near the seabed.

The carapace of T. gainesi (bottom), along with two symmetrical rigid plates (top), covered the head from below. They formed a three-part armor set that protected the head on all sides.

“These enigmatic animals certainly had a major impact on Cambrian seafloor ecosystems. Their front limbs looked like multiple stacked rakes and would have been very efficient at carrying whatever they caught with their tiny spines into their mouths. The huge shell dorsal could have worked as a plow, “Caron said.

The Titanokorys fossils were found in Marble Canyon, located in northern Kootenay National Park, which has been the site of many Cambrian fossil discoveries dating back 508 million years. The site is part of the Burgess Shale, a well-preserved fossil deposit in the Canadian Rockies. The Burgess Shale is a Unesco world heritage site.

One such discovery includes the Cambroraster falcatus radiodonto, so named because the shell on its head is similar in shape to the Millennium Falcon from Star Wars. It is possible that these two species fought on the bottom of the sea in search of prey.

Titanokorys and other fossils collected from the Burgess Shale, will be on display in a new gallery at the Royal Ontario Museum beginning in December.