Years ago, when I was trying to give myself a crash course in paleo, I had assumed that the varied wonders of the Burgess Shale had already been found. That's the impression I came away from Stephen Jay Gould's Wonderful Life with - the Cambrian oddballs had been assembled, but it was their interpretation that kept shifting. But over the past few years researchers have underscored the fact that there's still an entire menagerie of strange Paleozoic creatures in the Burgess Shale that are only now being recognized. Kootenayscolex barbarensis is the latest to join the club.

Described by paleontologists Karma Nanglu and Jean-Bernard Caron, Kootenayscolex is one of those Cambrian critters that might not look too out of place if it were still squirming around today. It's an annelid, or segmented worm, that resembles its modern polychaete cousins known as bristleworms. But, as ever, the fossiliferous devil is in the details, and the 508 million-year-old Kootenayscolex bears some unusual traits that set it apart.

Consider the bristles. Kootenayscolex isn't unique for having them, but its their placement that's unusual. In addition to brushes along the side of the body, prominent bristles also stick out around the head and mouth of Kootenayscolex - something not seen before. Combined with studies of living annelids, Nanglu and Caron propose, this might mean that the annelid head is basically a more posterior body segment that was modified, which may say something about the early evolution of annelid bodies. Kootenayscolex and related worms may provide the key to understanding how our modern wrigglers came to be as they are. But there's an even simpler facet to the find. At the very least, that this new worm was discovered at all underscores that the Burgess Shale still has secrets for us. 

A lovely specimen of Kootenayscolex barbarensis. Credit: Jean-Bernard Caron Royal Ontario Museum

Name: Kootenayscolex barbarensis

Meaning: Kootenayscolex is a combination of Kootenay - the name of the national park where the fossils were found - and scolex, which is the head portion of annelid worms. The species name barbarensis honors Royal Ontario Museum volunteer Barbara Polk.

Age: Cambrian, about 508 million years ago. 

Where in the world?: Marble Canyon, British Columbia. 

What sort of organism?: An early polychaete worm.

How much of the organism’s is known?: Over 500 specimens.


Nanglu, K. Caron, J. 2018. A new Burgess Shale polychaete and the origin of the annelid head revisited. Current Biology. doi: 10.1016/j.cub.2017.12.019

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