Several evidences point to this evolutionary relationship. First, we leaned years ago that some dinosaurs had feathers. Second, the skeletons of theropod dinosaurs like velociraptor are very similar in structure to modern birds. However, there is one major exception to this similarity: the hand bones.
Birds wings are actually made in part from several bones that appear to be the modified second, third and fourth fingers. But in theropod dinosaurs, only the first, second and third fingers are present.
In skeleton of the newly described dinosaur species, Limusaurus inextricabilis, small bones of the first finger are preserved, as well as larger second, third, and fourth fingers. Thus, the hand-bones of Limusaurus are more like those of modern birds.
The scientists believe the progression from dinosaur to bird was not as direct as one might expect. But contrary to popular opinion, evolution is rarely direct. Still, this new skeleton sheds a little light on just how this important transition might have proceeded.
Illustration Credit: Portia Sloan