It was André Hubert Dumont (1809–1857) (Fig. 1) who, while mapping at the St Pietersberg south of Maastricht in the summer of 1849, noted that the higher portion of the yellowish-white friable limestones exposed there represented something unique. So unique that he coined a name for it (Dumont, 1849), his ‘système maestrichtien’, with a fossil hash level at its base, replete with faecal pellets. These pellets have since been described and formally named by Van Amerom (1971) as Coprulus maastrichtensis, and Dumont’s ‘système’ has been shown to correspond in part with our current concept of the Maastrichtian Stage, the youngest slice of Cretaceous time.

We report the discovery of a new species of marine reptile, a mosasaur, from the Upper Cretaceous (Maastrichtian) of The Netherlands. Prognathodon saturator sp. nov. is represented by an almost complete skull and much of the postcranial skeleton, and is one of the largest mosasaurs discovered to date. The stout skull and extremely massive jaws are more powerfully built than in any other known mosasaur. Bite marks, the partial disarticulation and scattering of the skeleton, and the presence of associated teeth of Squalicorax and Plicatoscyllium suggest extensive scavenging by sharks.