6. Cryptovolans, a four winged bird. The flight feathers on the hind legs gives Cryptovolans the appearance of being a bird equipped with four wings. It was originally thought that animals like Cryptovolans did not have any wings because they supposedly represented the ancestors of birds before flight had evolved. The discovery that Cryptovolans had the ability to fly revealed that dromaeosaurs were actually birds. Sculpture by Stephen Czerkas, © 2005.

7. Cryptovolans head shot. Cryptovolans means "hidden-flyer". It was a primitive bird that still had teeth. Sculpture by Stephen Czerkas, © 2005.