First Animals

By Jean-Bernard Caron, Richard M. Ivey Curator of Invertebrate Palaeontology at the Royal Ontario Museum

Royal Ontario Museum basecamp, Kootenay National Park, B.C. Elevation: 2,500 metres.

It’s 6:53 a.m. on Aug. 19, 2019. My body is primed to wake up — I beat my alarm clock by a couple of minutes. All is peace and quiet. The air inside the tent is cold, and it takes some conscious effort to abandon my cozy sleeping bag. As I step out of my tent, I am taken aback by the breathtaking mountainous scenery. Enchanting! What new secrets will these mountains reveal today?

After a hearty breakfast and enough caffeine to keep us running, the field crew and I are finally ready to hit the road, except there is no road ahead of us here … only a two-kilometre hike uphill! On our way out, the team is greeted by the squeaky call of a little pika, perhaps wishing us good luck. We reset the fence around our camp, charged with 5,000 volts of battery power to keep curious bears out, and slowly make our ascent in the shadow of the towering rock walls.

The first rays of sunshine light up the rocky slopes as we arrive at our destination. There is not a single sign or sound of civilization around us, just the distant rumbling of Tokumm Creek. We are standing on a small ledge at the foot of a huge cliff. Below us is a precipitous rocky slope with no end in sight. We tread carefully — the rocks are slippery.

Our team’s mission seems simple enough: to uncover the remains of animals fossilized within these rocks. Today, we might be lucky. We will see.

The Burgess Shale yields fossils half a billion years old

The rocks we are splitting are no ordinary stones: they belong to the famous Burgess Shale, a world-class paleontological deposit that was recognized as a UNESCO World Heritage site in 1980. Famous for the exceptional preservation of soft-bodied animals dating back to the Cambrian period, the Burgess Shale records a critical period in life history often referred to as the Cambrian explosion, which saw the global appearance and rapid evolution of animals in marine environments.

Take any animal today, on land or in the sea, and odds are good that there is a fossil from the Burgess Shale which can be connected to the base of its family tree. This story is featured in the new documentary First Animals from The Nature of Things.

Since its discovery in 1909 by Secretary of the Smithsonian Charles Walcott in neighbouring Yoho National Park, the original Burgess Shale site has yielded more than 200 species of soft-bodied animals. Normally, soft tissues decay after death, and animals that do not possess hard, mineralized structures like shells and bones will not leave any traces behind. The Burgess Shale, however, experienced conditions that did not let the natural forces of destruction occur. The result is a fantastic snapshot of animal life that existed in tropical marine seas just over half a billion years ago.

A game-changing discovery

In 2012, a century after the first Burgess Shale rocks were first split, we made a game-changing discovery. While prospecting in northern Kootenay National Park, about 40 kilometres south of Walcott’s original quarry, we uncovered spectacular new fossils. We named this new site “Marble Canyon” in reference to a narrow canyon carved by Tokumm Creek. Marble Canyon has since yielded many new species and key new specimens, including those of Metaspriggina, a fish-like animal with an early precursor of the spinal cord, and a very distant cousin of you and me.

This year, we have expanded our fieldwork activities just a few kilometres north of Marble Canyon. Thanks to the expertise of my friend and colleague Robert (Bob) Gaines from Pomona College in California, we targeted this new spot to conduct a small excavation, and in the few weeks since we started work here, our hopes have already been fulfilled.

Perhaps most strikingly, we have discovered dozens of examples of a strange carapace belonging to an animal that we had nicknamed “the spaceship” in previous years. (This type of carapace turned out to be the head shield of a newly described predatory arthropod now known as Cambroraster falcatus.) What more are we going to find?

MORE:
Uncovering Mother Nature's crazy experimental phase over half a billion years ago
Meet the weird, wacky and wonderful creatures that lived in Cambrian seas over 500 million years ago

New species waiting to be discovered

The day passes quickly with the team extracting large blocks of shale and splitting them open, the “tap-tap” sounds reminiscent of clockwork. Working here is like turning the pages of a giant history book, although the pages are not all there and many are only fragments.

The fossils we have collected quickly accumulate on rubber mats, waiting to be expertly inventoried, labelled and packed by Royal Ontario Museum technician Maryam Akrami. While smaller pieces are wrapped in a sheet of a local newspaper, larger slabs require the protection of surprisingly versatile pool noodles. Akrami is a Tetris virtuoso in her ability to tightly pack the oddly shaped pieces into five-gallon pails or larger trunks.

Gaines and I are working side by side now, trying to lift a particularly thick chapter of that history book with heavy pry bars. What lurks beneath? The shale has not been disturbed for more than half a billion years — nothing here. We lift another block. Will this be our lucky break? No.

Another block, and then — bingo! In front of our eyes lies a strange, helmet-like carapace almost the size of my head, which is huge by all Cambrian standards. This is another brand new species and much bigger than the regular “spaceship” we had found earlier. In all my years of fieldwork, I have never seen anything like it before! The entire crew rejoices around this newfound discovery, which in due course will get a proper scientific name.

It’s late August, and the weather is already getting cooler in this part of the Rockies. We do not have many more days of collecting before the snows will arrive. Fossil upon fossil, the pails pile up, ready to be picked up by our helicopter. Soon, it will be time to go home, though we have barely scratched the surface of these mountain slopes. Who knows what still lies inside.

Back at the museum, we unpack and examine the fossils in detail. And bit by bit, the extraordinary story of the world’s very first animals unfolds.

Watch First Animals on The Nature of Things.