Archaeopteryx dromaeosaurids and troodontids: jaws with sharp teeth, three fingers with claws, a long bony tail, hyperextensible second toes ("killing claw"), feathers (which also suggest warm-bloodedness), and various features of the skeleton. These features make "Archaeopteryx" a clear candidate for a transitional fossil between non-avian dinosaurs and birds. Thus, "Archaeopteryx" plays an important role, not only in the study of the origin of birds, but in the study of dinosaurs. It was named from a single feather in 1861. That same year, the first complete specimen of "Archaeopteryx" was announced. Over the years, ten more fossils of "Archaeopteryx" have surfaced. Despite
Dinosaur vision Dinosaur vision Dinosaur vision was, in general, better than the vision of most other reptiles, although vision varied between dinosaur species. Coelurosaurs, for example, had good stereoscopic or binocular vision, whereas large carnosaurs had poor binocular vision, comparable to that of modern alligators. Most carnosaurs, including "Carcharodontosaurus" and "Allosaurus", did not have very good binocular vision, comparable to modern alligators. They possessed binocular vision which was restricted to a region only 20° wide, which is understandable, as they hunted mostly large and slow prey. Their keenest sense was probably smell. Deinonychosaurs, like "Stenonychosaurus" and "Velociraptor", had better binocular vision than