The new tyrannosaurs are related (but not identical to) the ever-popular T. rex, but as such they are described as a distinctly unique species. In particular, the skeletons clearly show long, partially-preserved feathers. The scientists who described the new tyrannosaurs believe the feathers were used for insulation and/or show, due to the size and type of feathers.
T. rex lived during the Cretaceous period over 65 million years ago. The feathered tyrannosaurs lived before T. rex and had three fingers instead of two.