Traskasaura sandrae, a 12-m-long elasmosaur (a type of plesiosaur) that lived in the Cretaceous seas, 85 million years ago, had a strange mix of primitive and derived traits unlike any other elasmosaur; its unique suite of adaptations enabled this marine reptile to hunt prey from above.
Traskasaura sandrae. Image credit: O’Keefe et al., doi: 10.1080/14772019.2025.2489938.
The first Traskasaura fossil was discovered in 1988 from Late Cretaceous rocks of the Haslam Formation on Vancouver Island, Canada.
Since then, additional fossils have been recovered from the formation: an isolated right humerus and a well-preserved, juvenile skeleton comprising thorax, girdles and limbs.
First described in 2002, the fossils recently became famous, having been adopted by the Province of British Columbia and declared as the official fossil emblem of British Columbia.
“Plesiosaur fossils have been known for decades in British Columbia,” said Marshall University’s Professor F. Robin O’Keefe, lead author of the study.
“However, the identity of the animal that left the fossils has remained a mystery, even as it were declared BC’s provincial fossil in 2023.”
“Our new research published today finally solves this mystery.”
“The scientific confusion concerning this taxon is understandable.”
“It has a very odd mix of primitive and derived traits. The shoulder, in particular, is unlike any other plesiosaur I have ever seen, and I have seen a few.”
“With the naming of Traskasaura sandrae, the Pacific Northwest finally has Mesozoic reptile to call its own.”
“Fittingly, a region known for its rich marine life today was host to strange and wonderful marine reptiles in the Age of Dinosaurs.”
In the initial, 2002 description of the fossils, experts were reluctant to erect a new genus based solely on the adult skeleton of the elasmosaur discovered.
Relatively few characters were unambiguous on this particular skeleton.
However, a new, excellently preserved partial skeleton enabled the team to shed much new light on the morphology of the Puntledge River elasmosaur — and eventually identify it as a new genus and species.
Traskasaura sandrae had a very long neck — at least 36 well-preserved cervical vertebrae indicate at least 50 bones in the neck, and probably more.
“And whilst not huge amounts are known about Traskasaura sandrae’s behavior, the fascinating and long list of autapomorphic characters of the bones indicate strong capabilities for downward swimming,” Professor O’Keefe said.
“The combination of its unusual features relate to its hunting style — where it would use this capability for downward swimming to dive upon its prey from above.”
“This prey was likely the abundant ammonites known from the region.”
The findings appear in the Journal of Systematic Palaeontology.
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F. Robin O’Keefe et al. 2025. A name for the Provincial Fossil of British Columbia: a strange new elasmosaur taxon from the Santonian of Vancouver Island. Journal of Systematic Palaeontology 23 (1); doi: 10.1080/14772019.2025.2489938
