This is a great tooth from the marine reptile Nothosaurus spec.
The fossil comes from the layers of the upper Muschelkalk (MO3, Middle Triassic). It was found during the expansion of the A 3 motorway near Würzburg in Germany.
The tooth is comparatively large, it measures almost 3 cm and is located on an unbroken original matrix (10 x 11 cm)