T. rex had lips

Analysis of the teeth and skull of this king of the dinosaurs showed that, unlike its more recent relatives, the crocodiles, Tyrannosaurus rex probably had lips covering its formidable teeth. Most lizards have lips to keep their tooth enamel moist and their delicate dentition protected, and palæontologists have wondered for years whether T. rex was lippy like a lizard or lipless like a croc.