Burgess Shale fossil beds in B.C. reveal ancient ancestor of spiders, lobsters

An artistic reconstruction of the Yawunik kootenayi, including its distinctive whip-like feelers that it used to both catch its prey and sense its surrounding environment. (Lars Field/Phlesch Bubble)

A newly identified marine creature found in a shale site on the Alberta-B.C. border lived more than 509 millions years ago, more than 250 million years before the first dinosaur walked on the Earth.
The creature known as Yawunik kootenayi, was about 10 centimetres long, with two sets of eyes and three long claws, two of which were lined with teeth that were used to help it catch prey to eat. The claws also included long, whip-like appendages used to sense its surroundings.

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The Yawunik was an arthropod, which links it to modern day creatures like spiders, lobsters and butterflies. The fossil was identified by paleontologists at the University of Toronto and the Royal Ontario Museum, and Pomona College in California.
Cédric Aria, a PhD candidate at the University of Toronto and lead author of the study published this week in the journal Palaeontology, said that the Yawunik belongs to a "stem group" of arthorpods that makes it an ancestor of modern-day creatures as diverse as spiders, shrimp, lobsters, and ants.
"It has the signature features of an arthropod with its external skeleton, segmented body and jointed appendages, but lacks certain advanced traits present in groups that survived until the present day," Aria said.
He estimates that over 100 specimens of the Yawunik were found in the shale fields in Marble Canyon.

First of many new species ID'd

The creature was named in tribute to the Kootenay or Ktunaza First Nations, who lived in the Marble Canyon region. The Yawunik, meanwhile, was a fierce mythological sea creature.

A fossil of the Yawunik kootenayi, which lived about 509 million years ago, was found in the Marble Canyon shale field in B.C.'s Kootenay National Park. (Jean-Bernard Caron/Royal Ontario Museum)

"Yawunik is a central figure in the Ktunaxa creation story, and, as such, is a vital part of Ktunaxa oral history," said Donald Sam, Ktunaxa Nation Council Director of Traditional Knowledge and Language in the ROM's press release. "I am ecstatic that the research team recognizes how important our history is in our territory, and chose to honour the Ktunaxa through this amazing discovery."
It's the first creature identified from the Marble Canyon, a site located in B.C.'s Kootenay National Park. It's 40 kilometres away from the 505-million-year-old Burgess Shale in Yoho National Park, which is recognized as one of the most important fossil fields in the world.
Scientists first discovered the field in 2012, unearthing the remains of 50 animal species, 12 of them new to the science world. Aria explains that fossils in the Marble Canyon are unusually well-preserved, even including creatures' internal organs. That's thanks to the fine-grain mud that buried the creatures millions of years ago in an area of the canyon with water that had little or no oxygen, which reduced the ability for micro-organisms to decompose the fossils.
Aria says a second new arthropod will be announced to the public in the coming weeks, and that "those are the first of a long list" of new species to be identified.