Imagine a typical dinosaur: a monstrous, reptilian beast covered in scales. Now, in your mind’s eye, cover that same dinosaur with feathers. Hmmm. A new tyrannosaur fossil has got scientists thinking that perhaps this is what many dinosaurs really looked like. Xing Xu and Corwin Sullivan from the Chinese Academy of Sciences and their colleagues recently described a new, very large dinosaur from the Yixian Formation of northeastern China. Yutyrannus huali (meaning “beautiful feathered tyrant”) was a little smaller than its famous relative Tyrannosaurus rex – only 30 feet long from nose to tip of tail – and lived 60 million years before T. rex appeared on the scene. The Yutyrannus fossils were preserved exceptionally well (“exceptional preservation” is a formal phrase in paleontology) – well enough to see that this tyrannosaur was coated by layers of downy feathers. This could be evidence that many of the dinosaurs that paleontologists previously believed to be covered in scales instead sported feathery coats. Although other tyrannosaur family fossils have been found with feathers, none of these are as big as Yutyrannus huali. Paleontologists have previously assumed that feathers on small dinosaurs were a means of retaining warmth, therefore useful for the little guys with smaller surface areas. However, Yutyrannus’ bulk is forcing this hypothesis to be questioned. Perhaps Yutyrannus, which didn’t need a feather coat to keep its huge body warm, showed off its feathers to attract a mate as has been proposed for other early feather-bearers. Mark Norell, paleontologist at the American Museum of Natural History in New York, and codiscoverer of the first feathered tyrannosaurs, said that Yutyrannus has “rocked the world in terms of how we think of dinosaurs … Instead of giant lizards, they were basically weird birds.”
Read more at Wired Science.
The original article is in the April 5 issue of the journal Nature.