Yutyrannus is a theropod dinosaur from the Early Cretaceous of China. It was named in 2012 by Xu Xing and his associates. It was the largest confirmed feathered non-avian dinosaur to exist, and, for a small while, had brought in the possibility of larger theropods (specifically Tyrannosaurus, its relatively close cousin) being covered in feathers.
Physiology[]
Yutyrannus resembled a typical large theropod such as Allosaurus or Megalosaurus; it had a stout body, moderately long legs, a long tail, long arms with 3 fingers on each hand, a big head with large jaws, and a pair of horn-like crests atop its head. As well as this, it had a small, wavy crest atop its snout. Most of its body (excluding some of its legs, all of its snout, and possibly some of its head) would have been covered in short, fuzz-like feathers.
Diet[]
Yutyrannus was a predator, preying on ornithopods, mid-sized sauropods, small pterosaurs, and smaller theropods. Its teeth had knife-like serrations from front to back, and were used to cut into the hides of large prey.
Ecology[]
Yutyrannus is notable for being one of the largest theropods to be covered in feathers; it is regularly theorized that those feathers would have been for insulation (due to how relatively cold its environment was), but if the longest feathers were on the arms, they, along with the crests atop its head, would have been used for display. Since it was a tyrannosauroid like like Tyrannosaurus, it was previously presumed that the latter would have been covered in similar feathers, both for insulation and for display; however, so far, only scale impressions have been found from Tyrannosaurus and its close relatives (at least those more related to it than to Yutyrannus), meaning that the tyrannosaurids may have evolved scaly skin secondarily. In terms of how it lived, it is said that, due to alleged discoveries of a massive bonebed containing three individuals, it can be theorized that Yutyrannus hunted in packs (or at least in small family units, seeing as two of the individuals were juveniles); based on the alleged presence of sauropod bones from the same quarry, it is often speculated that sauropods would have been part of its diet as well (although how exactly it incorporated them into its diet is up for debate). Due to how primitive it was compared to Tyrannosaurus, it had long arms with 3 fingers on each hand (possibly for grasping onto prey); as well as this, even though its leg proportions would have allowed for swift movement, it had a short foot not adapted for running or even the stamina-efficient movement that Tyrannosaurus would have been capable of.