Massive new animal species discovered in half-billion-year-old Burgess Shale

Reconstruction of Titanokorys Gainesi. Credit: Lars Fields, Royal Ontario Museum
Palaeontologists at the Royal Ontario Museum (ROM) have uncovered the remains of a huge new fossil species belonging to an extinct animal group in half-a-billion-year-old Cambrian rocks from Kootenay National Park in the Canadian Rockies. In a Royal Society Open Science study, the findings were published on September 8, 2021.

This new species, Titanokorys gainesi was named. It is large and unusual. Titanokorys, which measured half a meter in length, was an enormous animal compared to other animals living in the oceans at the time. Most of these animals were barely the size of a pinky ring.

Jean-Bernard Caron is ROM's Richard M. Ivey Curator for Invertebrate Paleontology. "The sheer size and complexity of this animal is absolutely mind-boggling. This is one of the largest animals from the Cambrian Period ever found."

Evolutionarily, Titanokorys is part of a group called radiodonts. Anomalocaris is the most famous representative of this group. It may have been as long as a meter. Titanokorys, like all radiodonts had multifaceted eyes and a tooth-lined, pineapple-shaped mouth. It also had spiny claws beneath its head for prey capture. The body was equipped with flaps that allow it to swim. Some species in this group also had large, prominent head carapaces. Titanokorys was one of these.

Fossil from Titanokorys Gainesi Carapace Close Up Credit: Jean-Bernard Caron, Royal Ontario Museum

Titanokorys belongs to a subgroup called radiodonts called hurdiids. It has a long, thick head that is covered by a three-part, flexible carapace. Joe Moysiuk (a ROM-based Ph.D. candidate in Ecology & Evolutionary Biology from the University of Toronto) said that the head is so large relative to its body these animals are essentially swimming heads."

It is not clear why radiodonts have such a wide range of head carapace sizes and shapes. However, the Titanokorys flattened carapace suggests that this species was adapted for life on the seafloor.

These enigmatic creatures certainly had an impact on Cambrian seafloor ecosystems. Their front limbs looked like multiple stacked, rake-like rakes. They would have been extremely efficient in bringing whatever they caught in their tiny spines to the mouth. Dr. Caron said that the huge dorsal capace could have been used as a plough." He is also Associate Professor in Ecology & Evolutionary Biology at the University of Toronto and Moysiuk’s Ph.D. advisor.

The lower part of the Titanokorys gainesi's carapace (lower) was covered by two rigid plates (upper), which symmetrically covered the head from its underside. They formed a three-part armour set that protected the head from all angles. The illustration Titanokorys Gainesi shows them wrapping around the mouth and claws. Credit: Jean-Bernard Caron, Royal Ontario Museum

All fossils used in this study were found in Marble Canyon, northern Kootenay National Park. They were all collected by successive ROM expeditions. This area was discovered less than a decade ago and has produced a wide variety of Burgess Shale fossils dating back to the Cambrian Period. It also contains a smaller, more common relative to Titanokorys, Cambroraster falcatus, named for its Millennium Falcon-shaped headcarapace. The authors speculate that the two species may have been competing for the same bottom-dwelling prey.

Parks Canada manages the Burgess Shale fossil site in Yoho National Parks. Parks Canada is proud of its collaboration with top scientists to increase knowledge and understanding about this crucial period of earth's history. They also share these sites with the rest of the world via award-winning guided hikes. Because of its exceptional universal value, the Burgess Shale was made a UNESCO World Heritage Site by Canada's Rocky Mountain Parks in 1980.

Jean-Bernard Caron is Richard M. Ivey Curator for Invertebrate Paleontology, Royal Ontario Museum. He is seated over a fossil from Titanokorys gainsi, which was found at the quarry site in Kootenay Park. Credit: Joe Moysiuk. Joseph Moysiuk

The Discovery of Titanokorys Gainesi was featured in the CBC's The Nature of Things Episode "First Animals". These specimens and others from Burgess Shale will be displayed in a new gallery in ROM, The Willner Madge Gallery Dawn of Life. It is expected to open in December 2021.

More information: A giant nektobenthic radiodont from the Burgess Shale and the significance of hurdiid carapace diversity, Royal Society Open Science, royalsocietypublishing.org/doi/10.1098/rsos.210664 Journal information: Royal Society Open Science A giant nektobenthic radiodont from the Burgess Shale and the significance of hurdiid carapace diversity,

Royal Ontario Museum

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