Michel and Carine Plissart came across the remains while exploring a beach around 2023. Thought to belong to an ichthyosaur around 10 metres long, they are the first of their kind found in the Bridport Sand Formation.
Researchers at the University of Bristol are studying the fossil for clues about ancient marine life. The museum's new exhibition, Bridport's Sea Dragon: Unexpected Survivor, opened on 24 October and includes a film, a virtual-reality experience and expert talks.
The fossil has been donated to the museum, bringing an unusual new specimen to Dorset's Jurassic Coast collections.