0.5" Nanotyrannus Pre-Max Tooth from the Lance Formation of Wyoming. This nice pre-maxillary tooth of the Tyrannosaur Nanotyrannus has no serration but a very unique. All tyrannosaurs had these uniquely shaped teeth in the front of their top (maxilla) jaw. Some species have serrations, some have very faint serrations, and some have no serrations at all on these teeth. This tooth is about 69-66 million years old.