Sinornithosaurus-Dromaeosauridae fossil- 25×10×25 cm

Sinornithosaurus (genus name: Sinornithosaurus, meaning "Chinese bird-lizard") is a feathered dinosaur of the family Dromaeosauridae. Its fossils were found in the Yixian Formation of China, dating to the Middle Baremian Stage of the Lower Cretaceous [ 1]. Sinoornithosaurus was the fifth feathered dinosaur ever discovered, and when it was discovered in 1999, it was the closest feathered dinosaur to birds. Other dromaeosaurs, such as Velociraptor, are also thought to have feathers.

In 2009, American scientists found that Millennium China Ornithosaurus is the world's first dinosaur that can secrete venom. Like today's venomous snakes, it injects the venom from its fangs into its prey, effectively paralyzing it.