Clevosaurus (CLEE-vo-SORE-us) (Gloucester lizard) is an extinct genus of sphenodontian from the Triassic and the Jurassic periods of Nova Scotia (C. bairdi) and Yunnan (C. mcgilli). Clevosaurus was extremely like the modern tuatara in almost every way; They are different in only some features of the teeth and skull layout. They also differ in size. Clevosaurus was smaller than the modern Tuatara. Clevosaurus possibly ate plants as well as insects. This fact is known from Clevosaurus’s teeth. Clevosaurus is popular in cave systems in Great Britain. These caves also trapped Clevosaurus’s relatives and early mammals as well as dinosaurs. Clevosaurus is now believed to have had Pangaean distributiom.