What had spiky claws protruding from its mouth, sported a body shaped like a toilet brush, and looked like it had slipped off the cover of a science fiction novel? An oceanic predator from the Cambrian period known as the Stanleycaris Hirpex. The bizarre creature’s new fossils are exceptionally complete, preserving the brain, nervous system and a third eye.
Researchers from the Royal Ontario Museum (ROM) in Toronto recently announced the discovery of fossils belonging to this strange animal as part of an “astonishing” hoard of fossils dating back to 506 million years ago, according to a statement (opens in a new tab).
Paleontologists have found these ancient treasures in the Burgess Shale, a formation in the Canadian Rockies of British Columbia that is known for its abundant and well-preserved fossilized animal remains, and among fossils half a billion years there were many specimens of the predatory marine S. hirpex.
“What makes this discovery so remarkable is that we have dozens of specimens showing the remains of the brain and other elements of the nervous system, and they are incredibly well preserved and show really fine detail,” Joseph said. Moysiuk, lead author of a study describing the fossils and a PhD candidate in ecology and evolutionary biology from the University of Toronto.
“Before that, there had only been a few other finds of fossilized brains, particularly from the Cambrian period, but it’s still something quite rare, and it’s only something that’s been observed over the course of about the last 10 years,” Moysiuk said. Live Science. “Most of the species where we’ve seen fossilized brains, there’s only one or two specimens available.”
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Although small – measuring less than 8 inches (20 centimeters) long – S. hirpex was probably an imposing sight for its even smaller prey.
“He had this really ferocious apparatus of spiny claws and round mouth that made him absolutely ferocious,” Moysiuk said. “It also had long, rake-like spines to comb the seabed to flush out any buried organisms, side flaps to help it glide through the water, and trident-shaped spines that project toward each other. the other from the opposite appendage which we believe it used as a jaw to crush its prey.”
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Fossils show that the brain of S. hirpex was divided into two segments: the protocerebrum, which was connected to its eyes, and the deutocerebrum, which was connected to the frontal claws. This brain structure differs from the three-lobed structure of modern arthropods which are distant relatives of S. hirpex, such as insects. The brains of these modern relatives, in contrast, include a protocerebrum, deutocerebrum, and tritocerebrum, which connect the brain to an insect’s labrum, or upper lip, among other body parts.
“Preserving the brains of these animals gives us direct insight into the evolution of the nervous system from the perspective of the fossil record,” Moysiuk said.
Radiodonta, an extinct offshoot of the arthropod evolutionary tree which includes Stanleycaris, “is an important group to know about, as it offers us a better understanding of the evolution of modern arthropods.” said Moysiuk.
Another interesting aspect of S. hirpex was his oversized third median eye, a feature first seen in a radiodont. Although the study authors aren’t sure how the ancient arthropod used this eye, it may have helped the animal track its prey, Moysiuk suggested.
“Finding the Third Eye was a shock to us because we were starting to think we understood radiodonts pretty well and what they looked like,” he said. “For the first time, we were able to recognize this gigantic median eye in addition to the basic pair of eyes that we already knew from radiodonts.”
Although some modern arthropods, such as dragonflies and wasps, also have medial eyes, they are generally more sensitive than the other two eyes and yet do not focus as well. “We can only speculate, but we think that third eye helped orient an animal, and it’s especially important for a predator like Stanleycaris which needs to move quickly and precisely through the environment,” Moysiuk said.
Three of S. hirpex the fossils that were excavated during the excavation are now on permanent display at the Royal Ontario Museum in its Willner Madge Gallery, Dawn of Life.
The results were published July 8 in the journal Current biology (opens in a new tab).
Originally posted on Live Science.
