Also see this (sent to me by Comely1):

Oldest T. rex relative unveiled

Guanlong wucaii
(Image: Zhongda Zhang/IVPP)

An early forefather of Tyrannosaurus rex has been discovered. The 160 million-year-old fossil is the oldest tyrannosaur ever found. It has been named Guanlong wucaii – which is derived from the Chinese for “crowned dragon”.

    “The discovery of this new animal pushes the origin of the group containing T. rex further back in time and also shows that early tyrannosaurs had a much wider distribution than previously thought.”

Guanlong lies at the base of the lineage of tyrannosaurides
Eotyrannus was dwarfed by other predators in its environment
T. rex was a member of theTyrannosauridae family