Dinosaurs shrank continually into birds
Steady miniaturization and rapidly changing skeletons transformed massive animals
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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