The Globe and Mail has a fantastic piece on the newest fossil discoveries of animals that lived during the "Cambian Explosion" in British Columbia. The new locality has been dubbed "Marble Canyon". It features a slightly different assemblage of animals than what was found in the "Burgess Shale". The exact location has been kept secret; it is known that it resides in Kootenay National Park in British Columbia, Canada. One particular fossil of Sidneyia inexpectans might give us an indication of what it felt like to be caught in an underwater mudslide.
High up in the mountains of British Columbia’s Kootenay National Park, the exact location a secret, Jean-Bernard Caron shows me a slab of rock pried from the cliff face where we are standing. I can see something embedded in the surface, that to my untrained eye is little more than a grey-on-grey blob the size of a flattened tennis ball – nothing that I would suspect as having once been alive.
But to Dr. Caron, curator of invertebrate paleontology at the Royal Ontario Museum, the blob is immediately recognizable as Sidneyia inexpectans, an ancient species of arthropod that would have looked like a cross between a jumbo shrimp and a sowbug. Dr. Caron points out the traces of feather-like appendages. Then he tells me exactly what it was doing the moment it died.
“Defecating, actually,” he says, indicating a darker splotch projecting from what I presume was the creature’s rear end. “He was a bit stressed, I guess, during burial.”
No kidding. One minute, about 508 million years ago, the hapless arthropod was ambling along the seafloor near an underwater cliff. The next, it was caught up in a mudslide and swept into oxygen-starved waters, where it suffocated under a thick blanket of silt along with a menagerie of other weird beasts.
