The Yutyrannus huali dinosaur was an ancestor of the Tyrannosaurus rex, and also the largest feathered animal in history.
It was covered with soft filamentous feathers, was 9.1 meters long and had a mass of about 1,400 kilograms.
It was officially described in April 2012 after being discovered in the northwest of the Yixian Formation fossil deposit, China, which dates back about 125 million years .
The feathers were long, up to eight inches, and stringy . Due to the low preservation quality, it has not been possible to establish whether the filaments were simple or compound, wide or narrow.
The presence of feathers in a large basal tyrannosaurid suggests the possibility that later tyrannosaurids also had feathers, even as adults, despite their size.
However, the first feathered animal was another : in June 2000, the discovery of a 220 million-year-old fossilized animal with "proto- feathers" was announced. Called Longisquama insignis, it had hollow appendages on its back along with other features compatible with the plumage of today’s birds.
Longisquama means "long scales"; the species name insignis refers to its small size.