On Saturday 18 April, 14-year-old Lars Barten (14) from Rijkevoort village in Noord-Brabant province in the Netherlands, together with his father Jos, discovered a mosasaur fossil near Maastricht city in Limburg province.
The discovery includes tail, flipper, backbone and finger bones.
At the natural history museum in Maastricht, there will be more research on the fossils.
UPDATE July 2016: the fossil mosasaur, called Lars after its discoverer, was not yet an adult. Work on the fossil continues.