Since its discovery more than 100 years ago, Tyrannosaurus rex has reigned as king of the predatory dinosaurs. Popularized by countless books, television shows, and a certain 1993 movie, the "tyrant king" is well known to nearly everyone on Earth. It was a burly bear-faced monster with long banana-shaped teeth lining a mouth that could swallow a person whole. Tyrannosaurus stood on two strong legs, but had arms shorter than you or me. From snout to tail tip, its skin was covered in scales.
About that last bit though, are we sure it was scaly?
Tyrannosaurus and its closest kin, collectively known as tyrannosaurs, belong to a group of dinosaurs called coelurosaurs. They are known for their extremely birdlike anatomy and feathered fossils. These fossils show that dinosaurs' earliest feathers were hair-like. Over time, they evolved fluffy branched forms and eventually the flat-vaned feathers sported by birds we see today. The large tyrannosaurs from the latest Cretaceous, such as Tyrannosaurus, Tarbosaurus, Albertosaurus, and Gorgosaurus, left few skin impressions for us to study. These impressions were small, only about the size of a coin. From these impressions we can see that the feet and underside of the tail were covered in small scales.
