Traskasaura sandrae: The Strange 12-Metre Sea Lizard with “Grinding Machine” Teeth from North America

A bizarre new elasmosaurid plesiosaur, Traskasaura sandrae, has been formally named from Late Cretaceous fossils on Vancouver Island, British Columbia. Reaching up to 12 metres (39 feet) long, this “very odd” marine reptile combined primitive and advanced traits unlike any other known elasmosaur, revealing a powerful ambush predator equipped with robust, crushing teeth perfectly adapted for smashing shelled prey.

The story began in November 1988 when Michael Trask and his daughter Heather discovered the first specimen along the Puntledge River in the Haslam Formation. Dated to the Santonian stage (~86–84 million years ago), the fossils include neck vertebrae, a humerus, and an exceptionally preserved juvenile skeleton. Initially described in 2002 and later declared British Columbia’s official provincial fossil, the material defied classification until a 2025 international analysis unlocked its secrets.

Published May 23, 2025, in the Journal of Systematic Palaeontology by F. Robin O’Keefe and colleagues, the study highlights Traskasaura’s unique mosaic anatomy in its vertebrae and limbs. Most striking are its thick, blunt, “grinding-machine” teeth — suited for crushing ammonites such as Pachydiscus rather than piercing soft-bodied fish. This denтιтion, combined with powerful paddles, positions Traskasaura as a formidable hunter in the shallow seaways that once covered western Canada.

Named in honour of the Trask family and Sandra Lee O’Keefe (the late wife of the lead author), the holotype and additional material are housed at the Courtenay and District Museum.

As the first elasmosaurid formally named from British Columbia, Traskasaura sandrae dramatically expands our picture of Santonian marine ecosystems and proves that even well-known fossils can still deliver major surprises.