Research based on a collection of fossils from the Burgess Shale shows a bizarre-looking animal with three eyes that sheds light on the evolution of the brain and head of insects and spiders.

The study, published in the journal Current Biology, looked at 268 specimens collected in the 1980s and 1990s from a site in Yoho National Park in British Columbia and stored at the Royal Ontario Museum in Toronto.

Dozens of those fossils contained the brain and nervous system of the half-billion-year-old Stanleycaris, which was part of an ancient, extinct offshoot of the arthropod evolutionary tree called Radiodonta, distantly related to modern insects and spiders.

B次元官网网址淚tB次元官网网址檚 a once-in-a-lifetime kind of discovery,B次元官网网址� Joe Moysiuk, lead author of the study and a PhD candidate in ecology and evolutionary biology at the University of Toronto, said in an interview this week.

B次元官网网址淲e get so much information that we couldnB次元官网网址檛 get from the ordinary fossil record B次元官网网址� things like features of the brain. We can see how many segments the brain of this animal is made up of. We can see the processing centres for visual information extending into the eyes of the animal, giving us all kinds of information about the neuroanatomy of this extinct organism.

B次元官网网址淭hat, in turn, helps us to understand the evolution of the brain and nervous system of the group of modern animals we call the arthropods, so that includes things today like insects and spiders.B次元官网网址�

The fossils show the brain was composed of two segments, which he said has deep roots in the arthropod lineage and that its evolution likely preceded the three-segmented brain that characterizes present-day insects.

B次元官网网址淲e think that third segment was added somewhere along that branch that is the tree of life between the divergency of the velvet worms and the modern arthropods,B次元官网网址� explained Moysiuk.

Researchers, he said, were able to trace how the evolution of the brain segments occurred more than 500 million years ago.

B次元官网网址淭hatB次元官网网址檚 pretty incredible when you think we are looking at these fossils. You think of fossils as being mostly things like shells and bones, not things like brains.B次元官网网址�

Moysiuk said the right conditions were needed to preserve the small, compressed fossils of an animal that was about 20 centimetres in size.

B次元官网网址淭he organisms were preserved in these fast-flowing mudflows, so they were tumbling around and flattened in all kinds of orientations,B次元官网网址� said Moysiuk, noting most of the specimens were five centimetres or less.

B次元官网网址淪o, when we looked at the different fossils that we find from these different orientations of preservation, we are able to piece back together what the whole creature looked like in three dimensions.B次元官网网址�

Researchers found that the Stanleycaris, known as a predator in the Cambrian period, had an unexpected large central eye in front of its head in addition to its pair of stalked eyes.

B次元官网网址淚t emphasizes that these animals were even more bizarre-looking than we thought, but also shows us that the earliest arthropods had already evolved a variety of complex visual systems like many of their modern kin,B次元官网网址� Jean-Bernard Caron, MoysiukB次元官网网址檚 supervisor and curator of invertebrate paleontology at the Royal Ontario Museum, said in a news release.

B次元官网网址淪ince most radiodonts are only known from scattered bits and pieces, this discovery is a crucial jump forward in understanding what they looked like and how they lived.B次元官网网址�

Moysiuk said the finding also shows the importance of fossil collections.

B次元官网网址淭hereB次元官网网址檚 a lot of treasures that can be found by trolling through things that have been discovered a long time ago,B次元官网网址� he said.

B次元官网网址淲e have this incredible collection of Burgess Shale fossils at the Royal Ontario Museum.B次元官网网址�

B次元官网网址� Colette Derworiz, The Canadian Press