Dinosaurs shrank continually into birds
Steady miniaturization and rapidly changing skeletons transformed massive animals
THE DESCENT OF BIRDS Dinosaur ancestors of birds shrank steadily for more than 50 million years. Left to right: the ancestral neotheropod (about 220 million years old), tetanuran, coelurosaur, paravian and Archaeopteryx (150 million years old).
Davide Bonnadonna