An article published in the journal “Proceedings of the Royal Society B: Biological Sciences” reports the discovery of a new species of marine predator that lived in the Cambrian period, just over 500 million years ago, discovered in the famous Burgess Shale. Joe Moysiuk, a graduate student at the University of Toronto, and his supervisor Jean-Bernard Caron named this animal Cambroraster falcatus believing that its carapace had a certain resemblance to the Millennium Falcon.
An area of Kootenay National Park, in British Columbria, Canada, forms a part of the Burgess Shale, one of the most famous fossil deposits that for over a century has been revealing specimens in excellent state of preservation that sometimes represent new species. This area, about 40 kilometers away from the first deposit discovered in 1909, has been excavated since 2012.
Over one hundred fossils belonging to the species later named Cambroraster falcatus have been discovered in that area during these years. It was a stroke of luck, also because usually only fragments of that kind of animals are found. The new discovery allowed to study this animal in a very detailed way, identifying its peculiar characteristics such as the shape of the carapace and some rake-shaped claws, probably used to plough through the seabed to search for prey.
The researchers classified Cambroraster falcatus in the radiodont group, which also includes Anomalocaris, which in the Cambrian was a gigantic top predator with its meter in length. Its distant newly discovered relative was indeed smaller with a length of around 30 centimeters, however it still had a remarkable size by the standards of an era in which most animals were no more than a few centimeters long.
The position of radiodonts in the arthropod phylum isn’t well understood but Cambroraster falcatus had a carapace with deep notches accommodating the upward facing eyes like today’s arthropods such as horseshoe crabs. According to Joe Moysiuk it’s a case of evolutionary convergence that probably reflects similarities in the environment and way of life. This suggests the possibility that Cambroraster falcatus used its carapace to plough through sediments as it fed, just as horseshoe crabs do today.
The existence of Cambroraster falcatus just over 500 million years ago confirms that at the time there were already various predators with complex characteristics, which means that there were ecosystems in which the various species had different roles. It’s a period that came a few tens of millions of years after the Cambrian explosion, the largest diversification event in the history of life on Earth. Fossils like the ones from Burgess Shale are helping to reconstruct that crucial period.
