Tyrannosaurids, a group of theropod dinosaurs that includes the infamous Tyrannosaurus rex, share a close evolutionary relationship with birds. This connection is supported by a multitude of anatomical and paleontological evidence.
One of the most striking similarities between tyrannosaurids and birds is the presence of feathers. While tyrannosaurids were not capable of flight, they possessed feathers that likely served other purposes, such as insulation, display, or communication. Additionally, both groups share a number of skeletal features, including hollow bones, a three-toed foot structure, and a wishbone (furcula). Furthermore, molecular studies have identified genetic similarities between tyrannosaurids and modern birds.