PALEONTOLOGY PUZZLE: Traskasaura sandrae – The “Very Strange Sea Monster” 12 Metres Long with Powerful Crushing Teeth Discovered on Vancouver Island, Canada!

A bizarre 12-metre elasmosaurid plesiosaur from Late Cretaceous British Columbia has stunned scientists with its unprecedented “mosaic” anatomy — a strange blend of primitive and advanced traits that no other marine reptile possesses.

Formally described in May 2025 in the Journal of Systematic Paleontology by Robin O’Keefe and colleagues, Traskasaura sandrae is the first elasmosaurid named from British Columbia. The holotype was discovered in 1988 by Michael and Heather Trask along the Puntledge River in the ~85-million-year-old Haslam Formation on Vancouver Island. Two additional specimens (a humerus and a juvenile skeleton) were later recovered.

What sets Traskasaura apart is its extraordinary combination of features: a relatively narrow mandible armed with large, robust, crushing teeth — reminiscent of much earlier, more primitive forms — paired with highly derived neck and limb adaptations that enabled powerful downward swimming and ambush attacks from above. This heavy denтιтion suggests it specialised in hard-shelled prey such as ammonites, a feeding strategy unknown in other elasmosaurids.

Named in honour of the Trask family and Sandra Lee O’Keefe, the species was declared British Columbia’s provincial fossil in 2023. At 12 metres long, it was a formidable predator in the northern Pacific waters of the Santonian stage.

The discovery proves that even well-studied groups like elasmosaurids can hide extraordinary evolutionary surprises. As researchers noted, Traskasaura was no ordinary long-necked plesiosaur — it was a true “very strange sea monster” that exploited a completely novel ecological niche. The Pacific Northwest has finally claimed its own Mesozoic marine icon.