Fossil of Stenopterygius, an extinct reptile- taken at Museo de la Naturaleza y el Hombre – Tenerife. Image: Wikipedia user Ghedoghedo
Stenopterygius is an extinct genus of thunnosaur ichthyosaur known from Europe (England, France, Germany, Luxembourg and Switzerland). Maximum length was 4 meters (13 feet). The habits of Stenopterygius were similar to those of present-day dolphins. It spent most of its life in the open sea, where it hunted fish, cephalopods and other animals. The abdominal cavity of skeletons of this ichthyosaur often contains the remains of such food.