It is one of the first and most primitive known tyrannosaurids, and had a casing of feathers. Its name refers to the connection of Tyrannosaurus rex with feathers: a mythological Chinese Dragon (Dilong), but with a paradoxical edge: its small size and its feathers.

The feathers were seen in a fossilized skin feeling of the jaw and tail. They are not urbanized as modern feathers, lacking a central shaft and used for warmth rather than flight. Adult tyrannosaurs, establish in Alberta and Mongolia have skin impressions which come into view to show the pebbly scales typical of other dinosaurs. Possibly the juveniles were feathered but shed them as the animal became larger.