Graciliraptor

Graciliraptor is the oldest named dromaeosaurid dinosaur known from good fossil remains.1

Its tail bones were very long and slender, and a thin sheet of bone connected them, making the tail stiff.1

Graciliraptor had features similar to early birds, like long tail bones and a small wrist bone that mainly touched the second finger.2

It was extremely lightly built, with long lower leg bones that helped it run fast.1

Graciliraptor lived in the same time and place as other early dromaeosaurs like Sinornithosaurus and Microraptor, but in slightly older rocks.1

The only known fossil includes parts of the skull, nearly complete arms and legs, and ten tail vertebrae.1