Matthew Myerscough, a civil engineer, discovered a 201-million-year-old plesiosaur jawbone at Lavernock Point in the Vale of Glamorgan. This type of marine reptile, also known as a "sea dragon," had not been found in Wales previously.
Myerscough, who took up amateur fossil hunting after experiencing post-traumatic stress disorder following an avalanche on Yr Wyddfa in 2014, said the activity helped his worries and stresses "melt away." He compared the focus required for fossil hunting to the mindfulness gained from yoga or sport.
The discovery was made when Myerscough and two other fossil hunters spotted a large shape in the limestone. Experts later identified it as the lower jaw of a rhomaleosaurus, a carnivore.
Research on the find is ongoing at National Museum Cardiff, and Myerscough expressed hope that it would lead to the publication of an academic paper.