The Crowned Tyrannosaur

Tyrannosaurus Rex may have been the 'king of the Dinosaurs', but it was one of it's ancestors that wore a crown.
Found in the China this early Tyrannosaurid from the Late Jurassic was named Guanlong (Crowned Dragon) because of it's distinctive crest.

Pencil drawing of the head of Guanlong wucaii by Renato Santos

Guanlong is the oldest relative of Tyrannosaurus yet found, older even than Dilong. It is therefore a very basal Tyrannosaurid with the slender build, long arms (with three-fingered hands), and a long narrow snout common to most Coelurosaurs.
It did however have a number of specializations that put it clearly in the Tyrannosaur clade. Like T. rex and all other Tyrannosaurs Guanlong had two types of teeth, with the smaller front teeth being shaped like scrapers. The foremost bone of the jaw was also very high, giving Guanlong the relatively blunt snout common to all Tyrannosaurs.

Tyrannosaurus Teeth - The crowns of a king

The teeth of Tyrannosaurus are unlike any other, they are highly specialized for killing and eating other Dinosaurs. They are not only famously large and recurved (or "banana-shaped"), but they are also placed for maximum effect.

Teeth of Tyrannosaurus Rex

Allosaurus and T. rex (not to scale)

Tyrannosaurus did not have the hatched-shaped head common to most Theropods, rather the head of a T. rex was comparatively wide ending in a blunt snout.
The teeth of a Tyrannosaur were also different in shape from those of other Theropods. Where almost all Theropods had flat blade-like teeth for slicing through meat, Tyrannosaurs had teeth that were decidedly more rounded (in some teeth almost circular) for punching through flesh and crushing bone. Tyrannosaurus in fact had three distinct types of teeth in it's jaws.