Make that distant cousins –?the newfound, relatively diminutive 10-foot-long tyrannosauroids pre-dated the T. rex branch of their family tree by about 100 million years. That makes them the oldest known as well as the most primitive tyrannosauroid fossils ever found.
The discovery of the oldest tyrannosaurs is described in the journal Nature on Feb. 9. Erickson co-authored the paper with seven scientists from China, the United States and Canada.
Until now, tyrannosaurs such as T. rex were best known from the end of the Cretaceous period, about 65-70 million years ago. The new, nearly complete skeletons from China offer a snapshot of the earliest tyrannosauroid just after they morphed into a different branch of the family tree –?95 million years before cousin T. rex ruled the roost.
Researchers say the identification of the oldest basal (primitive) tyrannosauroid yet will shed light on the early evolution and geographical distribution of its ancestors –?small therapod dinosaurs known as coelurosaurs that were the closest relatives of modern-day birds.
"It's not only the oldest tyrannosaur but also the sexiest," Erickson said, what with its flashy crest atop its small head –?an extravagant ornament likely used only for attraction and display purposes and the first of its kind seen in the tyrannosaur's predatory family. The creature has been named "Guanlong wucaii" and translated loosely from Chinese, that's "crowned dragon five colors."
An internationally known expert on the development and evolution of the vertebrate musculoskeletal sy
Source:Florida State University