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| Kourisodon puntledgensis |
These waters belonged to the mosasaurs—sleek, powerful marine reptiles that ruled the global oceans with quiet authority.
Since their first discovery in 1766, their bones have surfaced from nearly every corner of the world—New Zealand to Antarctica, Africa to Europe, the Americas to Japan—whispers of a dynasty that once circled the globe.
And yet, some of their most intriguing stories are written close to home.
Along the banks of the Puntledge River on Vancouver Island, a remarkable assemblage has come to light. Here, tucked into ancient marine sediments, we find the remains of both elasmosaurids and mosasaurs—echoes of a coastal ecosystem long vanished beneath forest and freshwater flow.
As Dan Bowen of the Vancouver Island Paleontological Society notes, this stretch of river has yielded not one, but multiple marine reptiles from a time when this land lay beneath a teeming inland sea.
The first mosasaur material recovered here—around ten vertebrae belonging to Platecarpus—was discovered by Tim O’Bear and carefully excavated by a dedicated team led by Dr. Rolf Ludvigsen. Later prepared by Bowen and Joe Morin, these bones offer a tantalising glimpse of fast-moving predators that once patrolled these waters.
But it is a second discovery that truly sharpens the tale.
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| Kourisodon photo by Roland Tanglao |
What emerged was Kourisodon puntledgensis—a name drawn from the Greek kourís and odon, meaning “razor tooth,” and an apt one at that.
Small by mosasaur standards—roughly 3.75 to 4.5 metres in length—Kourisodon was nonetheless a nimble and capable predator.
First described within the “Leiodontini” and now placed among the clidastines, it hunted with precision in Pacific waters rich with life. Alongside it swam long-necked elasmosaurids, turtles, and other mosasaurs, though notably absent were the polycotylids so common elsewhere.
What makes this animal especially intriguing is its story of place—and of connection.
The type specimen of Kourisodon puntledgensis comes from a single locality within the Santonian-aged Pender Formation along the Puntledge River—the very place that lends the species its name. And yet, across the vast Pacific, its relatives appear again in the Upper Cretaceous rocks of Japan’s Izumi Group.
There, fragmentary remains—including those of juveniles—hint at at least one additional, as-yet-unnamed species, distinguished by features such as longer maxillary teeth (Tanimoto, 2005; Caldwell & Konishi, 2007).
We see a similar trans-Pacific kinship echoed in the ammonites of these regions—shared lineages linking distant shores. But curiously, this connection does not extend inland. The marine reptiles of the Western Interior Seaway tell a different story entirely.
This is provinciality in action—ancient ecosystems shaped by geography, currents, and isolation. As detailed by Nicholls and Meckert (2002), the Pacific faunas of British Columbia evolved along their own path, distinct from their contemporaries to the east.
Today, a full-scale replica of Kourisodon puntledgensis—a sleek, 12-foot echo of those razor-toothed hunters—resides at the Canadian Fossil Discovery Centre in Morden, Manitoba. A long way from the Puntledge, perhaps, but still tethered to that riverbank story.
And the Puntledge continues to give.
It is also the home of a newly described elasmosaur—Traskasaura—named in honour of Mike, Pat, and Heather Trask. Discovered in 1988 and formally described in 2025, it adds yet another layer to this rich and ever-unfolding story of Vancouver Island’s ancient seas.
Stand along the Puntledge now, with the river slipping quietly past your boots, and you can almost feel it—the weight of deep time, the flicker of ancient oceans, the swift shadow of something moving just beneath the surface.
And, if you’ve spent enough time in the field, you’ll feel something else too.
The memory of those who walked these shores with you—who swung their last hammer, shared their last laugh, and left their stories folded gently into the stones we still turn over today.
References
Nicholls, E. L. and Meckert, D. (2002). Marine reptiles from the Nanaimo Group (Upper Cretaceous) of Vancouver Island. Canadian Journal of Earth Sciences 39(11):1591–1603.
Tanimoto, M. (2005). Mosasaur remains from the Upper Cretaceous Izumi Group of Southwest Japan. Netherlands Journal of Geosciences 84(3):373–378.
Caldwell, M., & Konishi, T. (2007). Taxonomic re-assignment of the first-known mosasaur specimen from Japan, and a discussion of circum-Pacific mosasaur paleobiogeography. Journal of Vertebrate Paleontology 27(2):517–520.
CBC News (2018). “Ferocious” new mosasaur skeleton coming to Morden.
CJOB (2018). “Ferocious, razor-like teeth”: new mosasaur comes to Morden's fossil centre.
Winnipeg News (2018). Morden museum's collection of mosasaur skeletons grows with new addition.
Image Two: By Roland Tanglao from Vancouver, Canada - Dinos at Courtenay Museum -20090628-7Uploaded by FunkMonk, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=10364342
